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Although trauma-hemorrhage (T-H) induces suppressed splenic dendritic cell (DC) maturation and antigen presentation capacity, it remains unclear whether IL-15 modulates splenic DC functions. The aim of this study therefore was to investigate the effect of IL-15 on splenic DC functions after T-H. Male C3H/HeN mice (6-8 wk old) were randomly assigned to T-H or sham operation. T-H was induced by midline laparotomy and ~90 min of hemorrhagic shock (blood pressure 35 mmHg), followed by fluid resuscitation (4 X the shed blood volume in the form of Ringer lactate). Two hours later, mice were killed, splenic DCs were isolated, and the effects of exogenous IL-15 on their costimulatory factors, major histocompatibility class II expression, ability to produce cytokines, and antigen presentation were measured. The results indicate that IL-15 production capacity of splenic DCs was reduced following T-H. Ex vivo exposure to IL-15 attenuated the suppressed production of TNF-[alpha], IL-6, and IFN-[gamma] from splenic DCs following T-H. In addition, expression of surface antigen studies demonstrate that exogenous IL-15 attenuated T-H-induced downregulation of the activation of DC. The suppressed splenic DC antigen presentation function following T-H was also attenuated by IL-15 treatment. Moreover, IL-15 enhanced IL-12-induced IFN-[gamma] production and antigen presentation by splenic DCs. These data suggest that ex vivo treatment with IL-15 following T-H provides beneficial effects on splenic DCs. The depression in IL-15 production by splenic DCs could contribute to the host's enhanced susceptibility to infections following T-H. antigen presentation; tumor necrosis factor-[alpha]; major histocompatibility class II

p38 MAPK has been reported to regulate the inflammatory response in various cell types via extracellular stimuli, p38 MAPK activation also results in the induction of heine oxygenase (HO)-1, which exerts potent anti-inflammatory effects. Although studies have shown that 17[beta]-estradiol ([E.sub.2]) prevented organ dysfunction following trauma-hemorrhage, it remains unknown whether p38 MAPK/HO-1 plays any role in [E.sub.2]-mediated attenuation of intestinal injury under those conditions. To study this, male rats underwent trauma-hemorrhage (mean blood pressure ~40 mmHg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, [E.sub.2] (1 mg/kg body wt), the p38 MAPK inhibitor SB-203580 (2 mg/kg body wt) or [E.sub.2] plus SB-203580. Two hours thereafter, intestinal myeloperoxidase (MPO) activity and lactate, TNF-[alpha], IL-6, ICAM-1, cytokine-induced neutrophil chemo-attractant (CINC)-1, and macrophage inflammatory protein (MIP)-2 levels were measured. Intestinal p38 MAPK and HO-1 protein levels were also determined. Trauma-hemorrhage led to an increase in intestinal MPO activity and lactate, TNF-[alpha], IL-6, ICAM-1, CINC-1, and MIP-2 levels. This was accompanied with a decrease in intestinal p38 MAPK activity and increase in HO-1 expression. Administration of [E.sub.2] normalized all the above parameters except HO-1, which was further increased following trauma-hemorrhage. Administration of SB-203580 with [E.sub.2] abolished the [E.sub.2]-mediated restoration of the above parameters as well as the increase in intestinal HO-1 expression following trauma-hemorrhage. These results suggest that the p38 MAPK/HO-1 pathway plays a critical role in mediating the salutary effects of [E.sub.2] on shock-induced intestinal injury. p38 MAPK inhibitor; CINC-1; MIP-2; MPO

Studies have shown that p38 MAPK and nitric oxide (NO), generated by endothelial NO synthase (eNOS), play key roles under physiological and pathophysiological conditions. Although administration of 17[beta]-estradiol ([E.sub.2]) protects cardiovascular injury from trauma-hemorrhage, the mechanism by which E2 produces those effects remains unknown. Our objective was to determine whether the [E.sub.2]-mediated activation of myocardial p38 MAPK and subsequent eNOS expression/phosphorylation would protect the heart following trauma-hemorrhage. To study this, male Sprague-Dawley rats underwent soft-tissue trauma (midline laparatomy) and hemorrhagic shock (mean blood pressure 35-40 mmHg for 90 min), followed by fluid resuscitation. Animals were pretreated with specific p38 MAPK inhibitor SB-203580 (SB; 2 mg/kg), and nonselective NO synthase inhibitor [N.sup.G]-nitro-L-arginine methyl ester (L-NAME; 30 mg/kg) 30 min before vehicle (cyclodextrin) or E2 (100 [micro]g/kg) treatment, followed by resuscitation, and were killed 2 h thereafter. Cardiovascular performance and other parameters were measured. [E.sub.2] administration following trauma-hemorrhage increased cardiac p38 MAPK activity, eNOS expression and phosphorylation at [Ser.sup.1177], and nitrate/nitrite levels in plasma and heart tissues; these were associated with normalized cardiac performance, which was reversed by SB administration. In addition, [E.sub.2] also prevented trauma-hemorrhage-induced increase in cytokines (IL-6 and TNF-[alpha]), chemokines (macrophage inflammatory protein-2 and cytokine-induced neutrophil chemoattractant-1), and ICAM-I, which was reversed by L-NAME administration. Administration of [E.sub.2] following trauma-hemorrhage attenuated cardiac tissue injury markers, myeloperoxidase activity, and nitrotyrosine level, which were reversed by treatment with SB and u-NAME. The salutary effects of E2 on cardiac functions and tissue protection following trauma-hemorrhage are mediated, in part, through activation of p38 MAPK and subsequent eNOS expression and phosphorylation. nitric oxide synthase; cytokine; chemokine; myeloperoxidase

Although splenic dendritic cell (DC) functions are markedly altered following trauma-hemorrhage, the mechanism(s) responsible for the altered DC functions remains unknown. We hypothesized that trauma-hemorrhage inhibits DC function via suppressing toll-like receptor 4 (TLR4) expression and mitogen-activated protein kinases (MAPKs). To examine this, male C3H/HeN (6-8 wk) mice were randomly assigned to sham operation or trauma-hemorrhage. Trauma-hemorrhage was induced by midline laparotomy and ~90 min of hypotension [blood pressure (BP) 35 mmHg], followed by fluid resuscitation (4x the shed blood volume in the form of Ringer lactate). Two hours later, mice were euthanized, splenic DCs were isolated, and the changes in their MAPK activation, TLR4-MD-2 expression, and ability to produce cytokines were measured. The results indicate that trauma-hemorrhage downregulated the lipopolysaccharide (LPS)-induced MAPK activation in splenic DCs. In addition to the decrease in MAPK activation, surface expression of TLR4-MD-2 was suppressed following trauma-hemorrhage. Furthermore, LPS-induced cytokine production from splenic DCs was also suppressed following trauma-hemorrhage. These findings thus suggest that the decrease in TLR4-MD-2 and MAPK activation may contribute to the LPS hyporesponsiveness of splenic DCs following trauma-hemorrhage. Hyporesponsiveness of splenic DCs was also found alter stimulation with the TLR2 agonist zymosan. Our results may thus explain the profound immunosuppression that is known to occur under those conditions. toll-like receptor 4 expression; splenic dendritic cell; toll-like receptors; lipopolysaccharide

p38 mitogen-activated protein kinase (MAPK) activates a number of heat shock proteins (HSPs), including HSP27 and [[alpha].sub.B]-crystallin, in response to stress. Activation of HSP27 or [[alpha].sub.B]-crystallin is known to protect organs/cells by increasing the stability of actin microfilaments. Although our previous studies showed that 17[beta]-estradiol (E2) improves cardiovascular function after trauma-hemorrhage, whether the salutary effects of E2 under those conditions are mediated via p38 MAPK remains unknown. Male rats (275-325 g body wt) were subjected to soft tissue trauma and hemorrhage (35-40 mmHg mean blood pressure for ~90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were injected intravenously with vehicle, [E.sub.2] (1 mg/kg body wt), [E.sub.2] + the p38 MAPK inhibitor SB-203580 (2 mg/kg body wt), or SB-203580 alone, and various parameters were measured 2 h thereafter. Cardiac functions that were depressed after trauma-hemorrhage were returned to normal levels by [E.sub.2] administration, and phosphorylation of cardiac p38 MAPK, HSP27, and [[alpha].sub.B]-crystallin was increased. The E2-mediated improvement of cardiac function and increase in p38 MAPK, HSP27, and [[alpha].sub.B]-crystallin phosphorylation were abolished with coadministration of SB-203580. These results suggest that the salutary effect of [E.sub.2] on cardiac function after trauma-hemorrhage is in part mediated via upregulation of p38 MAPK and subsequent phosphorylation of HSP27 and [[alpha].sub.B]-crystallin. heat shock proteins; [[alpha].sub.B]-crystallin; p38 mitogen-activated protein kinase inhibitor doi: 10.1152/ajpheart.01303.2006.

Although studies have shown that 17[beta]-estradiol ([E.sub.2]) prevents neutrophil infiltration and organ damage following trauma-hemorrhage, the mechanism by which [E.sub.2] inhibits neutrophil transmigration remains unknown. Macrophage migration inhibitory factor (MIF) is thought to play a central role in exacerbation of inflammation and is associated with lung injury. MIF regulates the inflammatory response through modulation of Toll-like receptor 4 (TLR4). Activation of TLR4 results in the release of proinflammatory cytokines and chemokines, which induce neutrophil infiltration and subsequent tissue damage. We hypothesized that E2 mediates its salutary effects in the lung following trauma-hemorrhage via negative regulation of MIF and modulation of TLR4 and cytokine-induced chemotaxis. C3H/HeOuJ mice were subjected to trauma-hemorrhage (mean blood pressure 35 [+ or -] 5 mmHg for ~90 min, then resuscitation) or sham operation. Mice received vehicle, [E.sub.2], or [E.sub.2] in combination with recombinant mouse MIF protein (rMIF). Trauma-hemorrhage increased lung MIF and TLR4 protein levels as well as lung and systemic levels of cytokines/chemokines. Treatment of animals with [E.sub.2] following trauma-hemorrhage prevented these changes. However, administration of rMIF protein with [E.sub.2] abolished the [E.sub.2]-mediated decrease in lung TLR4 levels, lung and plasma levels of IL-6, TNF-[alpha], monocyte chemoattractant protein-1, and keratinocyte-derived chemokine (KC). Administration of rMIF protein also prevented [E.sub.2]-mediated reduction in neutrophil influx and tissue damage in the lungs following trauma-hemorrhage. These results suggest that the protective effects of [E.sub.2] on lung injury following trauma-hemorrhage are mediated via downregulation of lung MIF and TLR4-induced cytokine/chemokine production. hemorrhagic shock; 17[beta]-estradiol; Toll-like receptor 4; myeloperoxidase; cytokines; chemokines doi:10.1152/ajplung.00479.2006

In this study, we examined whether IL-18 plays a role in lung inflammation following alcohol (EtOH) and burn injury. Male rats (~250 g) were gavaged with EtOH to achieve a blood EtOH level of ~100 mg/dl before burn or sham injury (~12.5% total body surface area). Immediately after injury, rats were treated with vehicle, caspase-1 inhibitor AC-YVAD-CHO to block IL-18 production or with IL-18 neutralizing anti-IL-18 antibodies. In another group, rats were treated with anti-neutrophil antiserum ~16 h before injury to deplete neutrophils. On day 1 after injury, lung tissue IL-18, neutrophil chemokines (CINC-1/CINC-3), ICAM-1, neutrophil infiltration, MPO activity, and water content (i.e., edema) were significantly increased in rats receiving a combined insult of EtOH and burn injury compared with rats receiving either EtOH intoxication or burn injury alone. Treatment of rats with caspase-1 inhibitor prevented the increase in lung tissue IL-18, CINC-1, CINC-3, ICAM-1, MPO activity, and edema following EtOH and burn injury. The increase in lung IL-18, MPO, and edema was also prevented in rats treated with anti-IL-18 antibodies. Furthermore, administration of anti-neutrophil antiserum also attenuated the increase in lung MPO activity and edema, but did not prevent the increase in IL-18 levels following EtOH and burn injury. These findings suggest that acute EtOH intoxication before burn injury upregulates IL-18, which in turn contributes to increased neutrophil infiltration. Furthermore, the presence of neutrophils appears to be critical for IL-18-meditaed increased lung tissue edema following a combined insult of EtOH and burn injury. inflammatory mediators; adhesion molecule; chemokines doi:10.1152/ajplung.00408.2006

Leukocyte infiltration, mediated by chemokines, is a key step in the development of organ dysfunction. Lung and liver neutrophil infiltration following traumahemorrhage is associated with upregulation of monocyte chemoattractant protein-1 (MCP-1). Because MCP-1 is not a major attractant for neutrophils, we hypothesized that MCP-I influences neutrophil infiltration via regulation of keratinocyte-derived chemokines (KC). To study this, male C3H/HeN mice were pretreated with MCP-1 antiserum or control serum and subjected to trauma-hemorrhage or sham operation. Animals were killed 4 h after resuscitation. One group of trauma-hemorrhage mice receiving MCP-1 antiserum was also treated with mufine KC during resuscitation. Plasma levels and tissue content of MCP-1 and KC were determined by cytometric bead arrays. Immunohistochemistry was performed to determine neutrophil infiltration; organ damage was assessed by edema formation. Treatment with MCP-1 antiserum significantly decreased systemic, lung, and liver levels of MCP-1 and KC following trauma-hemorrhage. This decrease in MCP-1 levels was associated with decreased neutrophil infiltration and edema formation in lung and liver following traumahemorrhage. Restitution of KC in mice treated with MCP-1 antiserum restored tissue neutrophil infiltration and edema. These results lead us to conclude that increased levels of MCP-1 cause neutrophil accumulation and distant organ damage by regulating KC production during the postinjury inflammatory response. neutrophils; inflammation; cell trafficking

Neutrophil infiltration is a key step in the development of organ dysfunction following trauma-hemorrhage (T-H). Although we have previously shown that 17[beta]-estradiol (E2) prevents neutrophil infiltration and organ damage following T-H, the mechanism by which E2 inhibits neutrophil transmigration remains unknown. We hypothesized that E2 prevents neutrophil infiltration via modulation of keratinocyte-derived chemokine (KC), a major attractant for neutrophils. To examine this, male C3H/HeN mice were subjected to T-H or sham operation and thereafter resuscitated with Ringer lactate and E2 (1 mg/kg body wt) or vehicle. Animals were killed 2 h after resuscitation, and Kupffer cells were isolated. Plasma levels and Kupffer cell production capacities of KC, TNF-[alpha], and IL-6 were determined by BD Cytometric Bead Arrays; lung mRNA expression of KC was measured with real-time PCR; myeloperoxidase activity assays were performed to determine neutrophil infiltration, and organ damage was assessed by edema formation. Treatment with E2 decreased systemic levels and restored Kupffer cell production of KC, TNF-[alpha], and IL-6, as well as KC gene expression and protein in the lung. This was accompanied with a decrease in neutrophil infiltration and edema formation in the lung. These results suggest that E2 prevents lung neutrophil infiltration and organ damage in part by decreasing KC during posttraumatic immune response. cytokines; estrogen; neutrophil infiltration; organ damage

Although endothelin-1 (ET-1) induces vasoconstriction, it remains unknown whether 17[beta]-estradiol ([E.sub.2]) treatment following trauma-hemorrhage alters these ET-1-induced vasoconstrictive effects. In addition, the role of the specific estrogen receptor (ER) subtypes (ER-[alpha] and ER-[beta]) and the endothelium-localized downstream mechanisms of actions of [E.sub.2] remain unclear. We hypothesized that [E.sub.2] attenuates increased ET-1-induced vasoconstriction following trauma-hemorrhage via an ER-[beta]-mediated pathway. To study this, aortic rings were isolated from male SpragueDawley rats following trauma-hemorrhage with or without [E.sub.2] treatment, and alterations in tension were determined in vitro. Doseresponse curves to ET-1 were determined, and the vasoactive properties of [E.sub.2], propylpyrazole triol (PPT, ER-[alpha] agonist), and diarylpropionitrile (DPN, ER-[beta] agonist) were determined. The results showed that trauma-hemorrhage significantly increased ET-1-induced vasoconstriction; however, administration of [E.sub.2] normalized ET-1-induced vasoconstriction in trauma-hemorrhage vessels to the shamoperated control level. The ER-[beta] agonist DPN counteracted ET-1-induced vasoconstriction, whereas the ER-[alpha] agonist PPT was ineffective. Moreover, the vasorelaxing effects of [E.sub.2] were not observed in endothelium-denuded aortic rings or by pretreatment of the tings with a nitric oxide (NO) synthase inhibitor. Cyclooxygenase inhibition with indomethacin had no effect on the action of [E.sub.2]. Thus, [E.sub.2] administration attenuates ET-1-induced vasoconstriction following trauma-hemorrhage via an ER-[beta]-mediated pathway that is dependent on endothelium-derived NO synthesis. estrogen receptor; nitric oxide; endothelium; aortic ring

Traumatic and/or surgical injury as well as hemorrhage induces profound suppression of cellular immunity. Although local anesthetics have been shown to impair immune responses, it remains unclear whether lidocaine affects lymphocyte functions following trauma-hemorrhage (T-H). We hypothesized that lidocaine will potentiate the suppression of lymphocyte functions after T-H. To test this, we randomly assigned male C3H/HeN (6-8 wk) mice to sham operation or T-H. T-H was induced by midline laparotomy and ~90 rain of hemorrhagic shock (blood pressure 35 mmHg), followed by fluid resuscitation (4x shed blood volume in the form of Ringer lactate). Two hours later, the mice were killed and splenocytes and bone marrow cells were isolated. The effects of lidocaine on concanavalin A-stimulated splenocyte proliferation and cytokine production in both sham-operated and T-H mice were assessed. The effects of lidocaine on LPS-stimulated bone marrow cell proliferation and cytokine production were also assessed. The results indicate that T-H suppresses cell proliferation, Th1 cytokine production, and MAPK activation in splenocytes. In contrast, cell proliferation, cytokine production, and MAPK activation in bone marrow cells were significantly higher 2 h after T-H compared with shams. Lidocaine depressed immune responses in splenocytes; however, it had no effect in bone marrow cells in either sham or T-H mice. The enhanced immunosuppressive effects of lidocaine could contribute to the host's enhanced susceptibility to infection following T-H. shock; bone marrow cells

Tissue hypoxia is a common sequel of trauma-hemorrhage but can occur even without blood loss under hypoxic conditions. Although hypoxia is known to upregulate Kupffer cells (KC) to release cytokines, the precise mechanism of release remains unknown. We hypothesized that Src family kinases play a role in mediating KC mitogen-activated protein kinase (MAPK) signaling and their cytokine production after hypoxia. Male C3H/HeN mice received either Src inhibitor PP1 (1.5 mg/kg body wt) or vehicle 1 h before hypoxia. KCs were isolated 1 h after hypoxia, lysed, and immunoblotted with antibodies to Src, p38, ERK1/2, or JNK proteins. In addition, KCs were cultured to measure interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) production. Hypoxia produced a significant increase in KC Src and MAPK (p38, ERK, JNK) activity compared with normoxic controls. This was associated with an increase in IL-6 and MCP-1 production. Treatment with PP1 abolished the increase in KC Src activation as well as p38 activity. However, PP1 did not prevent the increase in KC ERK1/2 or JNK phosphorylation. Furthermore, administration of PP1 prevented the hypoxia-induced increase in IL-6 but not MCP-1 release by KC. Additional in vitro results suggest that p38 but not ERK1/2 or JNK are critical for KC IL-6 production. In contrast, the production of MCP- 1 by KC was found to be independent of MAPK. Thus hypoxia increases KC IL-6 production by p38 MAPK activation via Src-dependent pathway. Src kinases may therefore be a novel therapeutic target for preventing immune dysfunction following low-flow conditions in trauma patients. innate immunity; macrophages; cell signaling doi:10.1152/ajpcell.00076.2006.

Although androstenediol (adiol or 5-androstene-3[beta],17[beta]-diol), a metabolite of dehydroepiandrosterone (DHEA), has protective effects following trauma-hemorrhage (T-H), it remains unknown whether administration of adiol has any salutary effects on the inflammatory response and outcome following a combined insult of T-H and sepsis. Male rats underwent T-H shock [mean arterial pressure (MAP) 40 mmHg for 90 min] followed by resuscitation. Adiol (1 mg/kg body wt) or vehicle was administered at the end of resuscitation. Sepsis was induced by cecal ligation and puncture (CLP) at 20 h after T-H or sham operation. Five hours after CLP, plasma and tissue samples were analyzed for cytokines (IL-6 and IL-10), MPO, neutrophil chemotactic factor (CINC-3), and liver injury (alanine aminotransferase and lactate dehydrogenase). In another group of rats, the gangrenous cecum was removed at 10 h after CLP, the cavity was irrigated with warm saline and closed in layers, and mortality was recorded over 10 days. T-H followed by CLP produced a significant elevation in plasma IL-6 and IL-10 levels, enhanced neutrophil cell activation, and resulted in liver injury. Adiol administration prevented the increase in cytokine production, neutrophil cell activation, and attenuated liver injury. Moreover, rats subjected to the combined insult, receiving vehicle or adiol, had a 50% and 6% mortality, respectively. Since adiol administration suppresses proinflammatory cytokines, reduces liver damage, and decreases mortality after the combined insult of T-H and sepsis, this agent appears to be a novel adjunct to fluid resuscitation for decreasing T-H-induced septic complications and mortality. liver enzymes; proinflammatory cytokines; neutrophils activation; myeloperoxidase doi:10.1152/ajpgi.00390.2005

Although 17[beta]-estradiol (E2) administration after trauma-hemorrhage attenuates lung injury in male rodents, it is not known whether the salutary effects are mediated via estrogen receptor (ER)-[alpha], or ER-[beta]. We hypothesized that the salutary effects of E2 lung are mediated via ER-[beta]. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure 40 mmHg for 90 min. then resuscitation). E2 (50 [micro]g/kg), ER-[alpha], agonist propyl pyrazole triol (PPT; 5 [micro]g/kg), ER-[beta] agonist diarylpropiolnitrile (DPN; 5 [micro]g/kg), or vehicle (10% DMSO) was injected subcutaneously during resuscitation. At 24 h after trauma-hemorrhage or sham operation, bronchoalveolar fluid (BALF) was collected for protein concentration. LDH activity, and nitrate/nitrite and IL-6 levels. Moreover, lung tissue was used for inducible nitric oxide synthase (iNOS) mRNA/protein expression, nitrate/nitrite and IL-6 levels, and wet/dry weight ratio (n = 6 rats/group). One-way ANOVA and Tukey's test were used for statistical analysis. The results indicated that E2 downregulated lung iNOS expression after trauma-hemorrhage. Protein concentration, LDH activity, and nitrate/nitrite and IL-6 levels in BALF and nitrate/nitrite and IL-6 levels in the lung increased significantly after trauma-hemorrhage: however, administration of DPN but not PPT significantly improved all parameters. Moreover, DPN treatment attenuated trauma-hemorrhage-mediated increase in iNOS mRNA/protein expression in the lung. In contrast, no significant change in the above parameters was observed with PPT. Thus the salutary effects of E2 on attenuation of lung injury are mediated via ER-[beta], and ER-[beta]-induced downregulation of iNOS likely plays a significant role in the DPN-mediated lung protection after trauma-hemorrhage. shock; propyl pyrazole triol; diarylpropiolnitrile

Although studies indicate that 17[beta]-estradiol administration after trauma-hemorrhage (T-H) improves cardiac and hepatic functions, the underlying mechanisms remain unclear. Because the induction of heat shock proteins (HSPs) can protect cardiac and hepatic functions, we hypothesized that these proteins contribute to the salutary effects of estradiol after T-H. To test this hypothesis, male Sprague-Dawley rats (~300 g) underwent laparotomy and hemorrhagic shock (35-40 mmHg for ~90 min) followed by resuscitation with four times the shed blood volume in the form of Ringer lactate. 17[beta]-estradiol (1 mg/kg body wt) was administered at the end of the resuscitation. Five hours after T-H and resuscitation there was a significant decrease in cardiac output, positive and negative maximal rate of left ventricular pressure. Liver function as determined by bile production and indocyanine green clearance was also compromised after T-H and resuscitation. This was accompanied by an increase in plasma alanine aminotransferase (ALT) levels and liver perfusate lactic dehydrogenase levels. Furthermore, circulating levels of TNF-[alpha], IL-6, and IL-10 were also increased. In addition to decreased cardiac and hepatic function, there was an increase in cardiac HSP32 expression and a reduction in HSP60 expression after T-H. In the liver, HSP32 and HSP70 were increased after T-H. There was no change in heart HSP70 and liver HSP60 after T-H and resuscitation. Estradiol administration at the end of T-H and resuscitation increased heart/liver HSPs expression, ameliorated the impairment of heart/liver functions, and significantly prevented the increase in plasma levels of ALT, TNF-[alpha], and IL-6. The ability of estradiol to induce HSPs expression in the heart and the liver suggests that HSPs, in part, mediate the salutary effects of 17[beta]-estradiol on organ functions after T-H. heme oxygenase-l; organ dysfunction; tumor necrosis factor-[alpha]; estrogen; injury

Although previous studies have shown that flutamide improves cardiovascular function after trauma-hemorrhage, the mechanisms responsible for the salutary effect remain unknown. We hypothesized that flutamide mediates its beneficial effects via an estrogen-dependent pathway through upregulation of peroxisome proliferator-activated receptor-[gamma] coactivator 1 (PGC-1). PGC-1, a key regulator of cardiac mitochondrial ATP production, induces mitochondrial DNA (mtDNA)-encoded genes such as cytochrome-c oxidase (COX) subunit I, II, and III (COX I, COX II, and COX III), which regulates mitochondrial oxidative phosphorylation. To test this hypothesis, male rats underwent trauma-hemorrhage (mean arterial pressure of 35-40 mmHg for ~90 min) followed by resuscitation. At the onset of resuscitation, rats received vehicle, flutamide (25 mg/kg body wt), flutamide in combination with estrogen receptor (ER) antagonist ICI-182,780 (3 mg/kg body wt), or ICI-182,780 alone. Flutamide administration after trauma-hemorrhage restored the depressed cardiac function and increased cardiac testosterone, estrogen levels, and arornatase activity. These increases were accompanied by normalized cardiac ER-[alpha] and ER-[beta] protein levels, PGC-1, and COX I mRNA expression, mitochondrial COX activity, and ATP contents. However, cardiac dihydrotestosterone, 5[alpha]-reductase II, androgen receptor protein levels, and mtDNA-encoded genes COX II and COX III were unaffected by flutamide treatment. The flutamide-mediated restoration of cardiac function, the increases in aromatase activity and estrogen levels, ER-[alpha], ER-[beta], PGC-1, COX I, COX activity, and ATP contents were, however, abolished when ER antagonist ICI-182,780 was administrated along with flutamide. These findings suggest that the salutary effect of flutamide on cardiac function after trauma-hemorrhage is mediated via an estrogen-dependent pathway through upregulation of PGC-1. hemorrhagic shock; heart; sex hormones; estrogen receptor-[alpha]; estrogen receptor-[beta]; peroxisome proliferator-activated receptor-[gamma] coactivator 1

A growing body of evidence indicates that heme degradation products may counteract the deleterious consequences of hypoxia and/or ischemia-reperfusion injury. Because heine oxygenase (HO)-1 induction after adverse circulatory conditions is known to be protective, and because females in the proestrus cycle (with high estrogen) have better hepatic function and less hepatic damage than males after trauma-hemorrhage, we hypothesized that estrogen administration in males after trauma-hemorrhage will upregulate HO activity and protect the organs against dysfunction and injury. To test this hypothesis, male Sprague-Dawley rats under-went 5-cm laparotomy and hemorrhagic shock (35-40 mmHg for 93 [+ or -] 2 min), followed by resuscitation with four times the shed blood volume in the form of Ringer lactate. 17[beta]-Estradiol and/or the specific HO enzyme inhibitor chromium mesoporphyrin (CrMP) were administered at the end of resuscitation, and the animals were killed 24 h thereafter. Trauma-hemorrhage reduced cardiac output, myocardial contractility, and serum albumin levels. Portal pressure and serum alanine aminotransferase levels were markedly increased under those conditions. These parameters were significantly improved in the 17[beta]-estradiol-treated rats. Estradiol treatment also induced increased HO-1 mRNA expression, HO-1 protein levels, and HO enzymatic activity in cardiac and hepatic tissue compared with vehicle-treated trauma-hemorrhage rats. Administration of the HO inhibitor CrMP prevented the estradiol-induced attenuation of shock-induced organ dysfunction and damage. Thus the salutary effects of estradiol administration on organ function after trauma-hemorrhage are mediated in part via upregulation of HO-1 expression and activity. hemorrhagic shock; heme oxygenase-1; chromium mesoporphyrin; liver; heart

Recent studies have shown that administration of dehydroepiandrosterone (DHEA) after trauma-hemorrhage (T-H) improves cardiovascular and hepatic function in male animals. Although androstenediol, one of the DHEA metabolites, has been recently reported to produce salutary effects on cardiac function and splanchnic perfusion after T-H, it remains unknown whether androstenediol per se has any salutary effects on hepatic function under those conditions. To study this, male Sprague-Dawley rats underwent laparotomy and ~90 min of hemorrhagic shock (35-40 mmHg), followed by resuscitation with four times the shed blood volume in the form of Ringer lactate. Androstenediol (1 mg/kg body wt iv) was administered at the end of resuscitation, and the animals were killed 24 h later. T-H significantly reduced portal blood flow, bile production, and serum albumin levels. Portal pressure, serum alanine aminotransferase, hepatic nitrate/nitrite, inducible nitric oxide synthase (iNOS), and endothelin-1 markedly increased after T-H. The alterations in these parameters induced by T-H were significantly attenuated in rats treated with androstenediol. Endothelial NOS (eNOS) expression, which was not different between T-H and sham, was found to be significantly elevated in T-H androstenediol-treated rats. These data suggest that improvement in hepatic perfusion by androstenediol after T-H is likely due to a decrease in endothelin-1 and induction of eNOS. Moreover, the decrease in hepatic damage after androstenediol administration is likely related to liver iNOS downregulation. Thus androstenediol appears to be a novel and useful adjunct for restoring hepatic function in male animals after adverse circulatory conditions. hemorrhagic shock; nitric oxide; nitric oxide synthase-2; adiol; 5-androstene-3[beta] 17[beta]-diol.

Role of IL-10 in regulating proinflammatory cytokine release by Kupffer cells following trauma-hemorrhage. Am J Physiol Gastrointest Liver Physiol 286: G942-G946, 2004. First published January 8, 2004; 10.1152/ajpgi.00502.2003.--IL-6 and TNF-[alpha] production by Kupffer cells is markedly stimulated following trauma-hemorrhage (T-H). Because IL-10 is an anti-inflammatory cytokine, the aim of this study was to determine whether IL-I0 regulates Kupffer cell proinflammatory cytokine release following T-H. To study this, we subjected adult male Sprague-Dawley rats to sham operation or T-H. The procedure involved a 5-cm midline laparotomy and ~90 min of hemorrhagic shock (35 mmHg), followed by resuscitation with four times the shed blood volume in the form of Ringer's lactate. At 2 h after the end of resuscitation, livers were perfused in vitro and perfusate was collected. In separate studies, Kupffer cells were isolated and incubated with different concentrations of anti-IL-10 MAb. IgG was used as control. After 16 h of incubation, IL-6 and TNF-[alpha] levels were measured by ELISA. Plasma IL-10 levels increased significantly following T-H. IL-10 levels in the perfusate and IL-10 production by cultured Kupffer cells were also significantly higher in the T-H group. When Kupffer cells were incubated with 10 [micro]g/ml of anti-IL-10 MAb, IL-6 and TNF-[alpha] production were significantly increased in both sham and T-H groups compared with those not treated with anti-IL-10 MAb. However, these changes were not observed when the cells were incubated with irrelevant (control) IgG. These results indicate that IL-10 production by Kupffer cells early after T-H may play a pivotal role in attenuating the proinflammatory cytokine environment, possibly in an autocrine/paracrine manner. isolated liver perfusion; anti-inflammatory cytokine; anti-interleukin-10 antibodies

Thromboxane [A.sub.2] (TX[A.sub.2]) and endothelin-1 (ET-1) have been proposed as the important vasoconstrictors that increase portal venous resistance in paracrine or autocrine fashion. We hypothesized that the hepatic damage following trauma-hemorrhage (T-H) is induced by the impaired hepatic circulation due to the increased production of vasoconstrictors such as ET-1 and TX[A.sub.2] by the liver. To test this, male Sprague-Dawley rats (n = 6/group) were subjected to trauma (i.e., midline laparotomy) and hemorrhage (35-40 mmHg for 90 min followed by fluid resuscitation) or sham operation. At 2 or 5 h after the end of resuscitation, the liver was isolated and perfused and portal inflow pressure, bile flow, and release of ET-1 and thromboxane [B.sub.2] (TX[B.sub.2]; a stable metabolite of TX[A.sub.]2) into the perfusate were measured. The level of portal pressure was higher at 5 h following T-H compared with 2 h after T-H and sham. The portal pressure was inversely correlated to the amount of bile production. Furthermore, the bile flow was significantly correlated to the hepatic damage as evidenced by release of lactate dehydrogenase into the perfusate. The level of ET-1 at 5 h following T-H in the perfusate after 30 min of recirculation did not show any difference from sham. However, the levels of TX[B.sub.2] in the T-H group were significantly higher than those in sham at that interval. These results indicate that the increased release of TX[A.sub.2] but not ET-1 following T-H might be responsible for producing the increased portal resistance, decreased bile production, and hepatic damage. endothelin; portal venous pressure; bile flow

Hypoxemia depresses cell-mediated immune functions in males, whereas proestrous females do not show such a depression. We hypothesized that elevated systemic estradiol levels in proestrous females prevent hypoxemia-induced immune depression. To study this hypothesis, male C3H/HeN mice were pretreated with 17[beta]-estradiol ([E.sub.2], 40 [micro]g/kg body wt sc) or vehicle for 3 days before induction of hypoxemia and again immediately before induction of hypoxia. The mice were subjected to hypoxemia (95% [N.sub.2]-5% [O.sub.2]) or sham hypoxemia (room air) for 60 min, and plasma and spleen cells were collected 2 h later. In vehicle-treated mice, splenocyte proliferation and interleukin-2 and interleukin-3 production were depressed after hypoxemia. [E.sub.2]-pretreated animals, however, displayed no such depression in splenic T cell parameters after hypoxemia. Splenic macrophage cytokine production was also depressed in vehicle-treated mice subjected to hypoxia, whereas it was normal in [E.sub.2]-pretreated mice. In summary, these findings indicate that administration of [E.sub.2] before hypoxemia prevented the depression of cell-mediated immune functions. Thus administration of 17[beta]-estradiol in high-risk patients before major surgery might decrease hypoxemia-induced immune depression under those conditions. inflammation; cytokines; estradiol; gender

Cyclooxygenase 2-mediated suppression of macrophage interleukin-12 production after thermal injury. Am J Physiol Cell Physiol 282: C263-C270, 2002; 10.1152/ajpcell.00357. 2001.--Macrophage (M[??]) prostaglandin (PG)[E.sub.2] production has been implicated in immunosuppression and increased susceptibility to sepsis after thermal injury. Deficient interleukin (IL)-12 production has also been implicated in these postburn complications. The present study examined the relationship between M[??] cyclooxygenase (COX)-2 activity and IL-12 production after thermal injury. C57BL/6 female mice were subjected to a 25% total body surface area full-thickness burn. M[??] were isolated 7 days later, or the mice were subjected to sepsis by cecal ligation and puncture (CLP). IL-12 production by M[??] from injured mice was suppressed by >50%, whereas COX-2 expression and PG[E.sub.2] production were increased twofold. The COX-2 inhibitor NS-398 suppressed PG[E.sub.2] production and normalized IL-12 production in the injury group, whereas it had no effect on IL-10 production. Injured mice subjected to CLP had lower IL-12 plasma levels compared with sham-treated mice subjected to CLP. NS-398 treatment prevented the suppression in plasma IL-12 levels in the injury group. Thus elevated M[??] COX-2 activity, independent of IL-10, suppresses M[??] IL-12 production after thermal injury and may play an important role in the observed immunosuppression under such conditions. prostaglandin [E.sub.2]; interleukin-10; immunosuppression; sepsis; burns

Research was conducted to examine the effects of depletion of male sex steroids by castration of male mice before mycobacterium infection. Male C3H/HeN mice were castrated and treated with pellets having either a vehicle or a combination of both steroid hormones for 14 days prior to soft tissue trauma and hemorrhagic shock or a sham operation. Results showed that castration increased the host resistance to infection. Findings indicate that male and female sex steroids exhibit divergent immunomodulatory characteristics with respect to cell-mediated immune responses after trauma-hemorrhage.

A hypoxemia-induced increase in macrophage-inducible nitric oxide synthase (iNOS) activity following hemorrhage may be partly the reason for the immune cell dysfunction similar to that associated with hemorrhagic shock. Male Sprague-Dawley rats were used to investigate whether hypoxia per se in the absence of any blood loss is a sufficient stimulus to cause iNOS expression and NO production by macrophages. Results showed that elevated expression of iNOS mRNA at 1.5 h after hypoxia preceded the increase in NO production by macrophages.