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Zoledronic acid (ZLD) is a bisphosphonate drug widely administered against pathological conditions such as hypercalcemia of malignancy, osteoporosis, bone metastases from solid tumors, and multiple myeloma. Unfortunately, renal injury is a serious and dose-limiting adverse effect of ZLD. There is no specific mechanism for ZLD-induced renal damage. The current study aimed to assess the effects of ZLD (10 and 15 mg/kg, i.p., single dose) on the rat kidney. In this regard, several parameters, including oxidative stress biomarkers, serum level of BUN and creatinine, inflammatory cytokines, kidney histopathology, and indices of mitochondrial function were assessed. A significant increase in serum Cr and BUN revealed renal injury. Moreover, kidney histopathological changes, including interstitial inflammation, tissue necrosis, and tubular atrophy, were detected in ZLD-treated rats. Biomarkers of oxidative stress, including a significant increase in reactive oxygen species (ROS), depletion of kidney glutathione (GSH) stores, increased lipid peroxidation, and suppression of the total antioxidant capacity, were detected in ZLD-treated animals. ZLD also significantly increased renal levels of TNF-α, IL-6, and IL-1β. ZLD exposure was also associated with significantly decreased mitochondrial dehydrogenases activity, mitochondrial depolarization, mitochondrial permeabilization, and ATP depletion. These data highlight mitochondrial dysfunction, inflammatory response, and oxidative stress as potential mechanisms in ZLD-induced kidney injury.

Cholestasis is not only influences the hepatic function but also damages many other organs. Lung injury is a critical secondary organ damage associated with cholestasis/cirrhosis. Pulmonary histopathological alterations, respiratory distress, and hypoxia are related to cholestasis/cirrhosis-induced lung injury. It has been found that oxidative stress plays a crucial role in this complication. The current study was designed to investigate the effect of N-acetyl cysteine (NAC) and dithiothreitol (DTT) as thiol-reducing and antioxidant agents against cholestasis-induced lung injury. Bile duct ligated (BDL) rats were monitored for the presence of inflammatory cells, TNF-α, and IgG levels in their broncho-alveolar fluid (BALF) at scheduled time intervals (3, 7, 14, and 28 days post-BDL surgery). These markers reached their highest level in the BALF of BDL rats on day 28 after the surgery. Therefore, in another set of experiments, the BDL animals were treated with NAC (100 and 300 mg/kg/day, i.p, for 28 consecutive days) and DTT (10 and 20 mg/kg/day, i.p, for 28 consecutive days). Meanwhile, a significant increase in the levels of TNF-α and IgG was detected in the BALF of BDL rats. The BALF level of neutrophils, monocytes, and lymphocytes was also significantly increased in cholestatic animals. A significant increase in lung tissue biomarkers of oxidative stress was detected in the BDL rats. It was found that NAC and DTT could significantly blunt pulmonary damage induced by cholestasis. The effects of these agents on oxidative stress biomarkers and inflammatory response seem to play a pivotal role in their mechanisms of protective properties.