Gentamicin Induced Nephrotoxicity: The Role of Sex Hormones in Gonadectomized Male and Female Rats

Estrogen Attenuates Diethylnitrosamine-Induced Hepatocellular Carcinoma in Female Rats via Modulation of Estrogen Receptor/FASN/CD36/IL-6 Axis

This study was designed to evaluate the potential protective impact of estrogen and estrogen receptor against diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in rats. The levels of liver injury serum biomarkers, liver content of interleukin-6 (IL-6), relative liver weight and distortion of liver histological pictures were significantly increased in ovariectomized (OVX) rats and SHAM rats that received DEN alone and were further exaggerated when DEN was combined with fulvestrant (F) compared to non-DEN treated rats. The OVX rats showed higher insults than SHAM rats. The tapering impact on these parameters was clear in OVX rats that received estradiol benzoate (EB), silymarin (S) or orlistat (ORS). The immunohistochemistry and/or Western blot analysis of liver tissues showed a prominent increase in fatty acid synthase (FASN) and cluster of differentiation 36 (CD36) expressions in OVX and SHAM rats who received DEN and/ or F compared to SHAM rats. In contrast to S, treatment of OVX rats with EB mitigated DEN-induced expression of FASN and CD36 in liver tissue, while ORS improved DEN-induced expression of FASN. In conclusion, the protective effect against HCC was mediated via estrogen receptor alpha (ER-α) which abrogates its downstream genes involved in lipid metabolism namely FASN and CD36 depriving the tumor from survival vital energy source. In addition, ORS induced similar mitigating effect against DEN-induced HCC which could be attributed to FASN inhibition and anti-inflammatory effect. Furthermore, S alleviated DEN-induced HCC, independent of its estrogenic effect.

Acute kidney injury induced by glycerol is worsened by orchiectomy and attenuated by testosterone replacement

Although several studies have demonstrated that the male gender represents an independent risk factor for renal disease, evidence shows that androgens exert renal protective actions. The findings are controversial and no studies have evaluated the effects of orchiectomy and testosterone replacement on glycerol-induced renal injury. Male Wistar rats were submitted to orchiectomy or sham surgery and divided into four groups: SC, sham control rats injected with NaCl; SG, sham rats injected with glycerol; OG, orchiectomized rats injected with glycerol; OGT, orchiectomized rats injected with glycerol and testosterone. Testosterone was administered daily for 14 days in the OGT group. After 11 days of testosterone replacement in the OGT group, SC rats were submitted to a saline injection, while SG, OG and OGT rats received glycerol. All rats were euthanized three days after injections. OG rats presented higher serum creatinine and urea, and sodium excretion, compared to SC and SG, while testosterone attenuated these changes. Acute tubular necrosis was also mitigated by testosterone. Renal immunostaining for macrophages, lymphocytes and NF-κB was higher in OG compared to SC and SG. In addition, renal interleukin-1β, Caspase 3 and AT1 gene expression was higher in OG rats compared to SG. Testosterone attenuated these alterations, except the NF-κB immunostaining. The renal NO was lower in OG rats compared to SG. Only the OG rats presented decreases in serum NO and renal HO-1, and increased TNF-α, angiotensinogen and AT1 expression compared to SC. We conclude that orchiectomy worsened glycerol-induced kidney injury, while testosterone attenuated this renal damage.

Amelioration of Renal Inflammation, Endoplasmic Reticulum Stress and Apoptosis Underlies the Protective Effect of Low Dosage of Atorvastatin in Gentamicin-Induced Nephrotoxicity

Gentamicin is a commonly used aminoglycoside antibiotic. However, its therapeutic use is limited by its nephrotoxicity. The mechanisms of gentamicin-induced nephrotoxicity are principally from renal inflammation and oxidative stress. Since atorvastatin, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, exerts lipid-lowering effects, antioxidant, anti-inflammatory as well as anti-apoptotic effects, this study aimed to investigate the protective effects of atorvastatin against gentamicin-induced nephrotoxicity. Male Sprague Dawley rats were used and nephrotoxicity was induced by intraperitoneal injection of gentamicin, 100 mg/kg/day, for 15 days. Atorvastatin, 10 mg/kg/day, was administered by orally gavage 30 min before gentamicin injection on day 1 to 15 (pretreatment) or on day 10 to15 (delayed treatment). For only atorvastatin treatment group, it was given on day 1 to 15. At the end of the experiment, kidney weight, blood urea nitrogen and serum creatinine as well as renal inflammation (NF-κB, TNFαR1, IL-6 and iNOS), renal fibrosis (TGFβ1), ER stress (calpain, GRP78, CHOP, and caspase 12) and apoptotic markers (cleaved caspase-3, Bax, and Bcl-2) as well as TUNEL assay were determined. Gentamicin-induced nephrotoxicity was confirmed by marked elevations in serum urea and creatinine, kidney hypertrophy, renal inflammation, fibrosis, ER stress and apoptosis and attenuation of creatinine clearance. Atorvastatin pre and delayed treatment significantly improved renal function and decreased renal NF-κB, TNFαR1, IL-6, iNOS and TGFβ1 expressions. They also attenuated calpain, GRP78, CHOP, caspase 12, Bax, and increased Bcl-2 expressions in gentamicin-treated rat. These results indicate that atorvastatin treatment could attenuate gentamicin-induced nephrotoxicity in rats, substantiated by the reduction of inflammation, ER stress and apoptosis. The effect of atorvastatin in protecting from renal damage induced by gentamicin seems to be more effective when it beginning given along with gentamicin or pretreatment.