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Objective: To explore the key targets and signaling pathways in the therapeutic mechanism of Semiliquidambar cathayensis Chang (SC) root against pancreatic cancer network pharmacology and molecular docking studies and cell experiments., Methods: The targets of SC and pancreatic cancer were predicted using the network pharmacological database, the protein-protein interaction network was constructed, and pathways, functional enrichment and molecular docking analyses were performed. CCK-8 assay was used to test the inhibitory effect of the aqueous extract of SC root on 8 cancer cell lines, and its effects on invasion, migration, proliferation, and apoptosis of pancreatic cancer cells were evaluated. Western blotting was performed to verify the results of network pharmacology analysis., Results: We identified a total of 18 active components in SC, which regulated 21 potential key targets in pancreatic cancer. GO and KEGG pathway enrichment analyses showed that these targets were involved mainly in the biological processes including protein phosphorylation, signal transduction, and apoptosis and participated in cancer signaling and PI3K-Akt signaling pathways. Among the 8 cancer cell lines, The aqueous extract of SC root produced the most obvious inhibitory effect in pancreatic cancer cells, and significantly inhibited the invasion, migration, and proliferation and promoted apoptosis of pancreatic cancer Panc-1 cells ( P < 0.05). Western blotting confirmed that SC significantly inhibited the phosphorylation levels of PI3K and AKT in Panc-1 cells ( P < 0.001)., Conclusion: The therapeutic effect of SC root against pancreatic cancer effects is mediated by its multiple components that act on different targets and pathways including the PI3K-Akt pathway.

Objective: Transforming growth factor beta 1 (TGF-β1) can promote myocyte hypertrophy, thus playing an important role in ventricular remodeling after myocardial infarction (MI)., Materials and Methods: In this study, the model of MI was established in rats through ligating the left anterior descending coronary artery. Subsequently, the messenger ribonucleic acid (mRNA) and protein expression levels of TGF-β1 in myocardial cells in both model group and sham operation group were determined. The effects of TGF-β1 treatment on myocardial cell apoptosis in MI rats were explored. Moreover, the changes of mitogen-activated protein kinase (MAPK) signaling pathway in rats with acute MI were verified. In addition, the protein expressions of phosphorylated-MAPK kinases 3/6 (p-MKK3/6) and MKK3/6 in myocardial cells of the two groups were analyzed., Results: The mRNA and protein expression levels of TGF-β1 in myocardial cells of acute MI rats were significantly higher than those in the sham operation group (p<0.01). After treatment with TGF-β1, the expression level of B-cell lymphoma 2 (Bcl-2) associated X protein (Bax) was obviously down-regulated. The Bax/Bcl-2 ratio was notably lower than that in control group (p<0.01). Meanwhile, the proportion of apoptotic cells decreased remarkably (p<0.01). In the model group, no evident change was observed in the protein expression level of MKK3/6, whereas the levels of p-MKK3/6 were prominently up-regulated (p<0.01)., Conclusions: TGF-β1 can activate MKK3/6 in the MAPK signaling pathway to resist the apoptosis of myocardial cells in acute MI rats.

Borax, a boron compound and a salt of boric acid, is known to inhibit the growth of tumor cells. HepG2 cells have been shown to be clearly susceptible to the anti-proliferative effects of borax. However, the specific mechanisms regulating this effect are poorly understood. This study aimed to investigate the pathways underlying the growth inhibition induced by borax in HepG2 cells. The effects of borax on HepG2 cell viability were characterized using MTT. Apoptosis was also verified by annexin V/propidium iodide staining. JC-1 dye and western blotting techniques were used to measure mitochondrial membrane potential and p53, Bax, and Bcl-2 protein expression, respectively. Relevant mRNA levels were measured by qRT-PCR. Borax inhibited the proliferation of HepG2 cells in a time- and dose-dependent manner in vitro. The apoptotic process triggered by borax involved the upregulation of p53 and Bax and the downregulation of Bcl-2, which was confirmed by a change in the mitochondrial membrane potential. These results elucidate a borax-induced apoptotic pathway in HepG2 cells that involves the upregulation of p53 and Bax and the downregulation of Bcl-2.

Lipid-associated membrane proteins (LAMPs) are important in the pathogenicity of the Mycoplasma genus of bacteria. We investigated whether Mycoplasma hyopneumoniae LAMPs have pathogenic potential by inducing apoptosis in a St. Jude porcine lung epithelial cell line (SJPL). LAMPs from a pathogenic strain of M. hyopneumoniae (strain 232) were used in the research. Our investigation made use of diamidino-phenylindole (DAPI) and acridine orange/ethidium bromide (AO/EB) staining, terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) analysis, and Annexin-V-propidium iodide staining. After LAMP treatment for 24 h, typical changes were induced, chromosomes were concentrated, apoptotic bodies were observed, the 3'-OH groups of cleaved genomes were exposed, and the percentage of apoptotic cells reached 36.5 ± 11.66%. Caspase 3 and caspase 8 were activated and cytochrome c (cyt c) was released from the mitochondria into the cytoplasm; poly ADP ribose polymerase (PARP) was digested into two fragments; p38 mitogen-activated protein kinase (MAPK) was phosphorylated; and the expression of pro-apoptosis protein Bax increased while the anti-apoptosis protein Bcl-2 decreased. LAMPs also stimulated SJPL cells to produce nitric oxide (NO) and superoxide. This study demonstrated that LAMPs from M. hyopneumoniae can induce apoptosis in SJPL cells through the activation of caspase 3, caspase 8, cyt c, Bax, and p38 MAPK, thereby contributing to our understanding of the pathogenesis of M. hyopneumoniae, which should improve the treatment of M. hyopneumoniae infections.

Breast carcinoma is the most common female cancer with considerable metastatic potential. Signal transducers and activators of the transcription 3 (Stat3) signaling pathway is constitutively activated in many cancers including breast cancer and has been validated as a novel potential anticancer target. Here, we reported our finding with nifuroxazide, an antidiarrheal agent identified as a potent inhibitor of Stat3. The potency of nifuroxazide on breast cancer was assessed in vitro and in vivo. In this investigation, we found that nifuroxazide decreased the viability of three breast cancer cell lines and induced apoptosis of cancer cells in a dose-dependent manner. In addition, western blot analysis demonstrated that the occurrence of its apoptosis was associated with activation of cleaved caspases-3 and Bax, downregulation of Bcl-2. Moreover, nifuroxazide markedly blocked cancer cell migration and invasion, and the reduction of phosphorylated-Stat3(Tyr705), matrix metalloproteinase (MMP) MMP-2 and MMP-9 expression were also observed. Furthermore, in our animal experiments, intraperitoneal administration of 50 mg/kg/day nifuroxazide suppressed 4T1 tumor growth and blocked formation of pulmonary metastases without detectable toxicity. Meanwhile, histological and immunohistochemical analyses revealed a decrease in Ki-67-positive cells, MMP-9-positive cells and an increase in cleaved caspase-3-positive cells upon nifuroxazide. Notably, nifuroxazide reduced the number of myeloid-derived suppressor cell in the lung. Our data indicated that nifuroxazide may potentially be a therapeutic agent for growth and metastasis of breast cancer.

The protein kinase inhibitor 7-hydroxystaurosporine (UCN-01) is one of the most potent and frequently used proapoptotic stimuli. The BH3-only molecule of Bcl-2 family proteins has been reported to contribute to UCN-01-induced apoptosis. Here we have found that UCN-01 triggers Puma-induced mitochondrial apoptosis pathway. Our data confirmed that Akt-FoxO3a pathway mediated Puma activation. Importantly, we elucidate the detailed mechanisms of Puma-induced apoptosis. Our data have also demonstrated that caspase-9 is a decisive molecule of Puma induction after UCN-01 treatment. Caspase-9 mediates apoptosis through two kinds of feedback loops. On the one hand, caspase-9 enhances Puma activation by cleaving Bcl-2 and Bcl-xL independent of caspase-3. On the other hand, caspase-9 directly activated caspase-3 in the presence of caspase-3. Caspase-3 could cleave XIAP in an another positive feedback loop to further sensitize cancer cells to UCN-01-induced apoptosis. Therefore, caspase-9 mediates Puma activation to determine the threshold for overcoming chemoresistance in cancer cells.

Diabetic cardiomyopathy is a common cardiac condition in patients with diabetes mellitus, which can result in cardiac hypertrophy and subsequent heart failure, associated with pyroptosis, the pro-inflammatory programmed cell death. MicroRNAs (miRNAs), small endogenous non-coding RNAs, have been shown to be involved in diabetic cardiomyopathy. However, whether miRNAs regulate pyroptosis in diabetic cardiomyopathy remains unknown. Our study revealed that mir-30d expression was substantially increased in streptozotocin (STZ)-induced diabetic rats and in high-glucose-treated cardiomyocytes as well. Upregulation of mir-30d promoted cardiomyocyte pyroptosis in diabetic cardiomyopathy; conversely, knockdown of mir-30d attenuated it. In an effort to understand the signaling mechanisms underlying the pro-pyroptotic property of mir-30d, we found that forced expression of mir-30d upregulated caspase-1 and pro-inflammatory cytokines IL-1β and IL-18. Moreover, mir-30d directly repressed foxo3a expression and its downstream protein, apoptosis repressor with caspase recruitment domain (ARC). Furthermore, silencing ARC by siRNA mimicked the action of mir-30d: upregulating caspase-1 and inducing pyroptosis. These findings promoted us to propose a new signaling pathway leading to cardiomyocyte pyroptosis under hyperglycemic conditions: mir-30d↑→foxo3a↓→ ARC↓→caspase-1↑→IL-1β, IL-18↑→pyroptosis↑. Therefore, mir-30d may be a promising therapeutic target for the management of diabetic cardiomyopathy.

Hepatocyte apoptosis is increased in patients with nonalcoholic steatohepatitis and correlates with disease severity. Long-chain saturated fatty acids, such as palmitate and stearate, induce apoptosis in liver cells. The present study examined insulin-mediated protection against saturated fatty acid-induced apoptosis in the rat hepatoma cell line, H4IIE, and primary rat hepatocytes. Cells were provided a control media (no fatty acids) or the same media containing 250 micromol/liter of albumin-bound oleate or palmitate for 16 h. Insulin concentrations were 0, 1, 10, or 100 nmol/liter (n=4-6/treatment). Palmitate, but not oleate, activated caspase-3 and induced DNA fragmentation in the absence of insulin. Insulin reduced palmitate-mediated activation of caspase-3 and DNA fragmentation in a dose-dependent manner. Phosphatidylinositol 3-kinase inhibitors abolished these effects of insulin. Insulin-mediated inhibition of palmitate-induced apoptosis was not due to an augmentation in the unfolded protein response or increased expression of genes encoding the inhibitor of apoptosis proteins, inhibitor of apoptosis protein-2 and X-linked mammalian inhibitor of apoptosis protein. Palmitate, but not oleate, increased c-Jun NH2 terminal kinase activity in the absence of insulin. Insulin or SP600125, a chemical inhibitor of c-Jun NH2 terminal kinase, blocked palmitate-mediated activation of c-Jun NH2 terminal kinase and reduced apoptosis. These data suggest that insulin is an important determinant of saturated fatty acid-induced apoptosis in liver cells and may have implications for fatty acid-mediated liver cell injury in insulin-deficient and/or -resistant states.

An immortal human hepatic cell line HL-7702 and human hepatoma cell line SMMC-7721 were treated with 3-30 microM SeO(2). SeO(2) at 30 microM markedly inhibited cell proliferation and viability, and prompted apoptosis of both normal hepatic and hepatoma cells after 48h treatment. SeO(2) could also down-regulate the Bcl-2 level, greatly in HL-7702 and slightly in SMMC-7721 cells, but up-regulate wild type P53 level a little in HL-7702 and significantly in SMMC-7721 cells. The Bcl-2/P53 value was closely correlated with the apoptotic rate as well as SeO(2) concentrations.

Experimental autoimmune thyroiditis (EAT) with granulomatous histopathology (G-EAT) can be induced by cells from mouse thyroglobulin (MTg)-immunized donors activated in vitro with MTg and IL-12. G-EAT lesions reach maximum severity 18-21 days after cell transfer and, if some thyroid follicles remain, lesions almost completely resolve by day 35. CD8(+) cells are required for G-EAT resolution. To begin to determine the mechanisms involved in G-EAT resolution, apoptosis in thyroids was analyzed by TUNEL staining. Apoptotic thyrocytes and inflammatory cells were present in the thyroids of both CD8(+) and CD8-depleted recipient mice at day 19-21. By day 35, apoptotic cells were rare in thyroids of mice whose lesions had resolved; the few apoptotic inflammatory cells were generally in close proximity to thyroid follicles. Thyroids of CD8-depleted mice had ongoing inflammation at day 35 and most apoptotic cells were thyroid follicular cells. The expression of Fas and Fas ligand (FasL) mRNA in thyroids was also determined by RT-PCR in both CD8(+) and CD8-depleted recipient mice. Fas was expressed in normal thyroids and its expression was relatively constant throughout the course of disease. FasL mRNA was not expressed in normal thyroids. FasL mRNA expression generally correlated with G-EAT severity, being maximal at day 21 and diminishing as lesions resolved. However, FasL mRNA expression in thyroids of CD8-depleted mice in which resolution was delayed was decreased compared to thyroids of CD8(+) mice with comparable disease severity, suggesting that FasL expressed by CD8(+) cells may play a role in G-EAT resolution.

Objective: To assess apoptotic status during the development of colorectal cancer and its prognostic value., Methods: The apoptotic frequency of 168 fresh adenocarcinoma specimens and primary cultured cells at 2, 12, 24 and 48 hours (9 normal mucosa, 4 adenomas and 9 adenocarcinomas) were measured by flow cytometry (FCM). Apoptotic indices (AI) in situ for 25 adenomas and 77 adenocarcinomas were visualized by TdT-mediated dUTP nick end labeling (TUNEL), Ki-s5 labeling indices (KI), bcl-2, bax, waf1 and p53 were immunostained with ABC method., Results: The culture-related apoptosis at 24-48 hours in vitro was obviously decreased in cultured tumor cells when compared with mucosa cells. Spontaneous apoptosis in situ occurred more frequently in tumor with aneuploid type at late stage. There was positive relationship between apoptosis and proliferative activity, determined by both TUNEL and FCM methods. The well-differentiated or early stage lesions with intensive bcl-2/bax expression were significantly more likely to have low AI. p53 accumulation and waf1 depression were mainly related to KI, whereas bax and waf1 overexpression led to a comparatively higher AI/KI ratio. bcl-2 and KI were found to be independent risk factors., Conclusions: The data suggest that the depressed susceptibility to inductive apoptosis may contribute to the initial phase of tumorigenesis, and spontaneous apoptosis in vivo may serve as a marker of tumor progression. The bcl-2 and KI may be valuable in predicting prognosis in colorectal cancer.

This study was intended to examine whether sulindac induces apoptosis in the HT-29 cells. Flow cytometry, transmission electron microscopy and DNA electrophoresis were used. Flow cytometry, transmission electron microscopy and DNA electrophoresis all demonstrated that sulindac could induce apoptosis of the HT-29 cell line in a time- and dose-dependent manner. After treatment with 0.3 mmol/L, 0.6 mmol/L and 1.2 mmol/L sulindac for 48 hours, apoptotic cells in the treatment groups reached 5.8%, 7.6% and 11.7% versus 2.9% in the control group; after treatment for 72 hours, apoptotic cells in the treatment groups increased to 12.5%, 15.4% and 24.4% versus 5.1% in the control group, respectively, P < 0.05. This study has demonstrated that colon adenocarcinoma HT-29 cell line can be induced by sulindac.

To investigate the mechanism and to observe the effectiveness of electrochemical therapy(ECT), 33 patients of late stage cancers which treated by ECT were included in this study. Flow cytometry (FCM) and pathology were used to observe the changes of tumor cells before and after ECT. Tumor cells of G1, G2/M, S phases and aneuploid cells were found to be killed almostly and the ratio of apoptosis was elevated greatly after ECT. Also, pathological evidence proved the death of tumor cells and some characters of apoptosis. So, ECT can non-selectively kill tumor cells and induce the apoptosis of them, and FCM was a way to evaluate the effectiveness of ECT.

Objective: To investigate the thermosensitizing effect of HSP70 antisense oligodeoxynucleolides (ODN) on cervical and ovarian cancer cells., Methods: Cervical cancer cell line Hela and ovarian cancer cell line MCAS were used to study their sensitivity to heat (42 degrees C, 1 hr) treatment. Heat-induced changes in cell viability was assessed by colony formation assay and apoptosis by cell morphology, agarose gel electrophoresis and flow cytometry., Results: Thermosensitivity of Hela and MCAS cells pretreated with HSP70 antisense ODN was increased as compared to cells treated with heat alone. The increase was antisense dose dependent. Although heat treatment or antisense ODN did induce apoptosis of HeLa and MCAS cells, the percentage of apoptotic cells was significantly increased when both heat and antisense ODN were applied. The effect was dependent on the dose of HSP70 antisense ODN., Conclusion: The thermosensitivity of ovarian cancer cells and cervial cancer cells can be increased by HSP70 antisense oligomer. Apoptosis may be involved in the increase in thermosensitivity.

Objective: To investigate the role of HSP70 in the proliferation and survival of ovarian carcinoma cells by inhibiting HSP70 expression with HSP70 antisense oligomer., Methods: Morphological changes of apoptotic cells were investigated by light microscopy. DNA fragmentation was analysed by agarose gel electrophoresis. Kinetics of induction of apoptosis and cell cycle were analysed by flow cytometry., Results: The HSP70 antisense oligomer treated ovarian carcinoma cells showed apparent inhibition of proliferation and characteristic morphological changes of apoptosis. Also, a ladder-like pattern of DNA fragments was demonstrated on agarose gel electrophoresis. HSP70 antisense-oligomer induced apoptosis of ovarian carcinoma cells mainly in G(1)/S phase in 8.3% to 41% at 1 to 20micromol/L. The apoptosis-inducting effect of HSP70 antisense oligomer was in a dose- and time-dependent manner., Conclusion: HSP70 antisense oligomer could not only inhibit the proliferation but also induce the apoptosis in ovarian carcinoma cells.

Objective: To study chemosensitivity and multidrug resistance of malignant bone tumors and to make an individual protocol of chemotherapy with sensitive antitumor agents., Methods: Apoptosis induced by MTX, ADM, MMC, VP-16, VCR and CTX, and chemosensitivity in 32 fresh specimens of malignant bone tumors were analyzed by flow cytometry (FCM) and quantitative immunofluorescence. The expression of P-glycoprotein (P170) in the specimen and the relation between P170, multidrug resistance, and chemosensitivity were detected., Results: The rate of apoptosis was significantly different in malignant bone tumor cells treated with different drugs: MTX (30.50 +/- 10.22)%, ADM (26.28 +/- 9.35)%, MMC (23.11 +/- 7.38)%, VP-16 (18.17 +/- 6.14)%, VCR (4.44 +/- 2.55)%, and CTX (1.22 +/- 0.59)%. The individual variation of cell apoptosis was prominent in the specimens of same pathological type treated with same agent. There was lower chemosensitivity in the malignant bone tumors with a high expression of P170., Conclusions: Chemosensitivity testing by flow cytometry is a simple, quick and sensitive assay. Quantitative analysis of expression of P170 could be used to predict multidrug resistance and its chemosensitivity of malignant bone tumors.

Objectives: To construct the recombinant adenovirus encoding antisense c-myc fragment and to investigate its effect on tumor cell proliferation and apoptosis., Methods: The shuttle plasmid encoding antisense c-myc was constructed by cloning c-myc cDNA fragment in the reverse direction into the pAdCMV. Then the plasmid pJM17 and the shuttle plasmid were co-transferred into 293 cells with liposome for homologous recombination to acquire recombinant adenovirus. The cell cycle, apoptosis, and the expression of related genes of the in vitro transferred human adenocarcinoma cell lines GLC-82 and SPC-A-1, as well as the human embryonic diploid lung cell line 2BS were studied. The effects on colony formation and treating effect on transplanted tumor in nude mice were also studied., Results: The recombinant adenovirus encoding antisense c-myc fragment was obtained with the titer of 3.3 x 10(10) pfu/ml. RT-PCR and Western blot showed that the expression of c-myc was reduced 3-5 days after infection. Simultaneously, obvious G1 arrest and apoptosis as well as the alteration of cyclin D1, bcl-2 and bax gene expression were observed in the infected tumor cells. The infected 2BS cells showed no such changes. The colony formation ability in vitro and the growth of the hetero-transplanted tumor in nude mice were also reduced., Conclusions: The reduced expression of c-myc gene could induce human adenocarcinoma cells tumor-cell-specific G1 arrest and apoptosis, while it has no effect on normal cell.

To investigate the effects of apoptosis on colorectal tumorigenesis and its possible biological significance, the apoptotic frequency in primary cultural cell of 9 normal mucosa, 4 adenomas and 9 adenocarcinomas in time period of 2, 12, 24, 48 hour was measured by flow cytometry. The apoptotic cells index (AI) in situ for 15 colorectal normal mucosa, 7 hyperplastic epithelial, 25 adenomas and 77 adenocarcinomas was identified by the terminal deoxynucleotidyl transferasemediated dUTP-biotin nick end labeling technique (TUNEL). Ki-67 proliferate index (KI), wafl and p53 genes were immunostained with ABC method. The results showed that culture related apoptotic incidence was obviously decreased in cultural tumor cell when compared with mucosa cell after 24-48 hour in vitro. There was a directly positive relationship between the spontaneous apoptosis and Ki-67-index in vivo. The well differentiated or early stage lesions with intensive bcl-2 expression were significantly more likely to have low AI and KI. Both mp53 accumulation and wafl depression which mainly related to KI, had no apparent correlation with AI, bcl-2/bax expression and clinicopathological features statistically; elevatory bax/bcl-2 and pervasive wafl depression led to an increasing AI/KI both in adenoma with atypia and in advanced cancer with distant metastasis or embolus, comparatively. The data indicated that the reduction of susceptibility to inductive apoptosis may contribute to the early phase of tumorigenesis, that AI in vivo may reflect proliferative activity, and that bcl family was closely associated with spontaneous apoptosis and biological behavior of human colorectal cancer.

Objective: To investigate induction of apoptosis and its possible mechanism in amiloride-treated ovarian carcinoma cell line., Methods: Morphological changes of apoptotic cells were investigated by light and fluorescence microscopy. DNA fragmentation was analysed by agarose gel electrophoresis. In addition, the number of hypodiploid cells (apoptotic cells) was quantitatively assessed by flow cytometry and intracellular pH was also analysed., Results: Amiloride-treated ovarian carcinoma cells showed morphological characteristics of apoptosis. A ladder-like pattern of DNA fragmentation was demonstrated on agarose gel electrophoresis. Amiloride at 0.01-5 mumol/L could induce apoptosis in 18.7%-61.6% of ovarian carcinoma cells. The apoptosis-inducing effect of amiloride was dose- and time-dependent. In addition, amiloride induced intracellular acidification in a subpopulation of the treated cells. Furthermore, these isolated acidified cells revealed chromatin condensation as well as DNA degradation with characteristics of apoptosis. There was good correlation between apoptotic cells and acidic cells., Conclusion: Amiloride triggers apoptosis of ovarian carcinoma cells; intracellular acidification may be involved in the mechanism of apoptosis.

To explore the effect of vasectomy on apoptosis of spermatogenic cells, we have detected apoptosis in the testis of vasectomized and sham-operated adult rats within a period of 12 postoperative weeks by means of flow cytometry and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuride triphosphate nick-end labeling) method. Flow cytometry found that, in vasectomized rat, the sub-haploid peak was higher and the percentage of cells with sub-haploid was increased. The total number of positive TUNEL cells in the vasectomized group was greater than that in the sham-operated group (P < 0.001). Compared with the same time-phased sham-operated subgroups, the number of apoptotic spermatogonia and primary spermatocytes in the testes of the subgroups 2 weeks, 6 weeks and 10 weeks after vasectomy as well as the number of spermatogonia of the subgroup 12 weeks after vasectomy were significantly higher (P < 0.05). These findings demonstrate that vasectomy could enhance the apoptosis of spermatogenic cells.

The effects of captopril and hydralazine, two commonly used antihypertensive drugs, on free radical generation and the onset of apoptosis in neuron and thymocyte preparations from 10-12 day old rats have been studied. Apoptosis was induced in neurons by kainate or N-methyl-D-aspartate and in thymocytes by heat shock. Intracellular free radical production was measured by 2',7'-dichlorofluorescein fluorescence, and apoptotic cells were detected by cell staining with fluorescein-labelled annexin V. Captopril was found to have no effect on intracellular free radical generation and also had no significant effect on the early stages of apoptosis in neurons and thymocytes. In contrast, hydralazine was found to decrease free radical generation in both neurons and thymocytes, and it also significantly decreased the numbers of apoptotic cells when neurons and thymocytes were stimulated for apoptosis. Hydralazine had a greater effect on decreasing free radical generation in neurons than in thymocytes, but it had a more pronounced effect on decreasing apoptosis in thymocytes compared to neurons, suggesting that apoptosis, under our experimental conditions, may not solely be triggered by free radical generation. These results contrast with earlier reports that captopril is a free radical scavenger and can decrease apoptosis in T-lymphocytes and cardiomyocytes, and the results obtained with hydralazine are in apparent disagreement with earlier reports that this drug is a free radical generator and can cause intracellular damage suggestive of enhanced free radical formation.