Pregnenolone protects the liver against doxorubicin-induced cellular injury by anti-inflammatory, antioxidant, and antiapoptotic mechanisms: role of Keap1/Nrf2/HO-1 and P-glycoprotein.

OBJECTIVE: Doxorubicin (DOX) is a widely used cytotoxic anthracycline antibiotic characterized by increased adverse effects that limit its clinical usefulness. Pregnenolone is a pregnane X receptor (PXR) agonist that increases the expression of xenobiotic transporters with anti-inflammatory and antioxidant potential. Thus, we hypothesized that pregnenolone would protect against DOX-induced hepatotoxicity. MATERIALS AND METHODS: Male Wistar rats (180-200 g) were randomized into four groups (n = 7): Control, Control + Pregnenolone (35 mg/kg/day, orally), DOX (15 mg/kg, i.p.) single dose on day five, and Pregnenolone + DOX. All treatments continued for seven consecutive days. Twenty-four hours after the last treatment, serum and liver tissues were collected for biochemical and histopathological assessment. The possible interaction between pregnenolone and DOX on cell viability was tested in HepG2 cells in vitro by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: DOX treatment resulted in hepatic damage and fibrosis with increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Liver samples of the DOX-treated group showed increased oxidative stress [malondialdehyde (MDA) and total nitrite/nitrate and decreased reduced glutathione (GSH) and superoxide dismutase (SOD)], increased hepatic tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), transforming growth factor-beta1 (TGF-ß1), and mRNA of interleukin-1beta (IL-1ß) and interleukin-6 (IL-6). Pretreating the rats with pregnenolone antagonized these DOX-induced effects. Moreover, pregnenolone upregulated the hepatic expression of Nrf2, heme oxygenase-1 (HO-1), and P-glycoprotein and decreased Keap1, opposing the effects of DOX. Moreover, pregnenolone prevented the DOX-induced activation and nuclear translocation of NFκB and increased cleaved caspase-3. Pregnenolone potentiated DOX-mediated cytotoxicity in HepG2 cells. CONCLUSIONS: These results illustrate the protective effects of pregnenolone against DOX-induced hepatotoxicity without limiting its anticancer activity.

Mechanism of grape seeds extract protection against paracetamol renal cortical damage in male Albino rats.

OBJECTIVE: The aim of the study was to assess the possible protective role of grape seeds extract (GSE) in ameliorating the toxic effects of paracetamol overdose on the rat renal cortical tissue. BACKGROUND: Paracetamol is one of the widely used non-steroidal anti-inflammatory drugs (NSAIDs). Unfortunately, it was reported as the most common cause of toxic ingestion in the world. Grape seeds extract (GSE) is known to have a strong antioxidant and anti-inflammatory properties. METHODS: The rats were divided into 4 groups; control group, GSE group, paracetamol group and GSE with paracetamol group. Kidney specimens were processed for biochemical, histological and immunohisto-chemical studies. RESULTS: The study showed marked biological changes in the form of significant increase in serum urea and creatinine levels with significant decrease in renal superoxide dismutase with paracetamol group. Furthermore, Proximal (PCT) and distal convoluted tubules showed marked degeneration, dense nuclear staining, cytoplasmic vacuolization, and partial loss of the brush borders. Most tubules were dilated, irregular and were filled with hyaline casts. PCT and DCT showed less PAS reaction and more COX-2 and caspase expression if compared with the control and the GSE groups. Concomitant administration of grape seeds extract with paracetamol revealed a noticeable amelioration of these biochemical and histological changes. Proximal and distal convoluted tubules showed less PAS reaction and more COX2 and caspase expression if compared with the control and the GSE. Concomitant administration of GSE with paracetamol revealed a noticeable amelioration of these biochemical and histological changes. CONCLUSION: Grape seeds extract provided biochemical and histo-pathological improvement in paracetamol induced renal cortical toxicity. These findings revealed that this improvement was associated with a decrease in oxidative damage and apoptosis (Tab. 1, Fig. 7, Ref. 55).

Eff ects of hemin, a heme oxygenase-1 inducer in L-arginine-induced acute pancreatitis and associated lung injury in adult male albino rats.

OBJECTIVE: The aim of the current study was to assess the protective outcome of hemin, a heme oxygenase-1 (HO-1) inducer on L-arginine-induced acute pancreatitis in rats. Acute pancreatitis (AP) is considered to be a critical inflammatory disorder with a major impact on the patient health. Various theories have been recommended regarding the pathophysiology of AP and associated pulmonary complications. METHODS: Twenty-four adult male albino rats were randomly divided into four groups: control group, acute pancreatitis (AP), hemin pre-treated AP group, and hemin post-treated AP group. RESULTS: Administration of hemin before induction of AP significantly attenuated the L-arginine- induced pancreatitis and associated pulmonary complications characterized by the increasing serum levels of amylase, lipase, tumor necrosis factor-α, nitric oxide, and histo-architectural changes in pancreas and lungs as compared to control group. Additionally, pre-treatment with hemin significantly compensated the deficits in total antioxidant capacities and lowered the elevated malondialdehyde levels observed with AP. On the other hand, post-hemin administration did not show any protection against L-arginine-induced AP. CONCLUSIONS: The current study indicates that the induction of HO-1 by hemin pre-treatment significantly ameliorated the L-arginine-induced pancreatitis and associated pulmonary complications may be due to its anti-inflammatory and antioxidant properties.

Possible contribution of nitric oxide and prostaglandin in the protective effect of angiotensin (1-7) against stress induced gastric ulceration in adult male albino rats.

To assess the gastro-protective potential of the angiotensin (Ang-) (1-7) on the gastric secretion and ulceration induced by cold restraint stress (CRS) in adult male rats and the possible contribution of nitric oxide and prostaglandin E2. Rats were pylorically ligated and divided randomly into the following groups (8 rats each): control, cold-restraint stressed (CRS), stressed Ang-(1-7) treated, stressed L-NNA-Ang-(1-7) treated, stressed Indo-Ang-(1-7) treated groups. Our results revealed that Ang-(1-7) pre-treatment proved to be protective against development of ulcerative lesions in CRS model as evidenced by histological examination and the reduction of the ulcer index and this could be mediated through reduction of free and total acidity and pepsin concentration of gastric secretion with significantly decreased lipid peroxidation and increased the gastric protective nitric oxide and prostaglandin E2 levels. Furthermore, Ang-(1-7) pre-treatment has anti-apoptotic effect, evident by its down-regulation of the CRS induced over-expression of the gastric caspase 3. In addition, the gastro-protective effects of Ang-(1-7) were significantly attenuated by co-administration with L-NNA or indomethacin. In conclusion, Ang-(1-7) can be considered a potential therapeutic agent to protect against the major clinical challenge of gastric injury resulting from stress. Nitric oxide and prostaglandin E2 seem to contribute to the Ang-(1-7)'s gastro-protective effect (Tab. 2, Fig. 5, Ref. 35).

Sodium hydrosulphide against renal ischemia/reperfusion and the possible contribution of nitric oxide in adult male Albino rats.

UNLABELLED: This study evaluates the effects produced by H2S donor; sodium hydrosulfide (NaHS), in a renal ischemia/reperfusion (IR) rat model and assesses the possible mediating role of nitric oxide (NO) in these H2S' effects. BACKGROUND: For several centuries, hydrogen sulfide (H2S) had been known to be a highly toxic agent. Recent studies, however, indicated that apart from NO and CO, H2S is the third "gasotransmitter" involved in the regulation of various physiological functions. Nevertheless, its impact on renal IR injury remains unclear. METHODS: Rats were randomly divided into three groups: sham control; renal IR; and renal IR+NaHS groups.NaHS (100 µmol/kg, ip) was administered 30 min prior to the induction of renal ischemia. RESULTS: NaHS was found to attenuate significantly the IR-induced elevations in the serum levels of urea, creatinine and tumor necrosis factor α (TNF-α) as compared with IR group. NaHS also significantly compensated the deficits in the total antioxidant capacities (TAC) and lowered the elevated malondialdehyde (MDA) levels observed with renal IR in renal, hepatic, pulmonary, and cardiac tissues. Furthermore, NaHS pretreatment down-regulated the renal IR-induced over-expression of inducible nitric oxide synthase (iNOS) and up-regulated the IR-induced suppression of endothelial nitric oxide synthase (eNOS). The loss of normal architecture, hemorrhage, and inflammatory cells infiltration detected by histopathological examination of renal, hepatic, pulmonary, and cardiac tissues in IR rats were markedly ameliorated by pre-ischemic NaHS treatment. CONCLUSION: NaHS protects against the effects of renal IR injury by acting primarily through a decrease in both pro-inflammatory cytokines and iNOS expression as well as through up-regulation of the eNOS pathway. Furthermore, H2S has a powerful anti-oxidant and anti-apoptotic effects (Tab. 2, Fig. 6, Ref. 45).