Xanthenone, ACE2 activator, counteracted gentamicin-induced nephrotoxicity in rats: Impact on oxidative stress and ACE2/Ang-(1-7) signaling.

Nephrotoxicity is a rapid deterioration of kidney function due to exposure to nephrotoxic drugs as gentamicin. Gentamicin increases the generation of reactive oxygen species (ROS) leading to inflammatory responses and nuclear factor-κB (NF-κB) activation. The renal renin-angiotensin system (RAS) is considered a crucial regulator for physiological homeostasis and disease progression through the classic ACE/Ang-II/AT1 axis and its antagonist, ACE2/Ang-(1-7)/Mas axis which exerts an important role in the kidney. The present study evaluates the protective effects of the angiotensin-converting enzyme 2 (ACE2) activator; xanthenone; against experimental nephrotoxicity induced by gentamicin. Rats were divided into 4 groups, normal control, xanthenone (2 mg/kg, s.c), gentamicin (100 mg/kg, i.p. for one week) and xanthenone + gentamicin groups. Blood urea nitrogen (BUN) and serum creatinine levels were measured. The kidney tissues were used for estimating glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), NF-κB, Angiotensin II (AngII), and Ang-(1-7). In addition, histopathological examination and Western blot analysis of ACE2 expression were done. Xanthenone significantly restored serum levels of BUN and creatinine. Xanthenone exerted significant antioxidant effect as revealed by increased GSH content and SOD activity together with reduced MDA content. It exerted anti-inflammatory effect by significant reduction in TNF-α, NF-κB and IL-6 expression compared to gentamicin group. Xanthenone increased Ang-(1-7) and ACE2 expression while significantly decreased Ang-II expression. Histopathologically, xanthenone markedly counteracted gentamicin-induced renal aberrations. Activation of ACE2/Ang-(1-7) by xanthenone produced significant antioxidant and anti-inflammatory effects that counteracted gentamicin-induced nephrotoxicity.

Thymoquinone mitigate ischemia-reperfusion-induced liver injury in rats: a pivotal role of nitric oxide signaling pathway.

Oxidative and nitrosative stress-induced endothelial cell damage play an essential role in the pathogenesis of hepatic ischemia-reperfusion (IR) injury. IR is associated with reduced eNOS expression and exacerbated by superimposed stress. NOSTRIN induces intracellular endothelial nitric oxide synthase (eNOS) translocation and inducible nitric oxide synthase (iNOS) increases nitric oxide (NO) production. Our aim was to assess hepatic expression of iNOS, eNOS, and NOSTRIN in IR with or without N-acetylcysteine (NAC) or thymoquinone (TQ) pretreatment and to compare their hepatoprotective effects. Surgical induction of IR was performed by occlusion of hepatic pedicle for 30 min with mini-clamp and reperfused for 30 min. The effects of TQ (20 mg/kg/day) or NAC (300 mg/kg/day) administered orally for 10 days were evaluated by serum ALT and AST, oxidative stress parameters, NO production, and histopathological analysis. Also, localization and expression of iNOS, eNOS, and NOSTRIN were assessed by immunofluorescence. TQ or NAC pretreatment significantly decreased elevated serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and myeloperoxidase (MPO) activities, malondialdehyde (MDA) level, and NO production. In addition, they restored the depleted GSH content and alleviated histopathological changes. Furthermore, they up-regulated eNOS and down-regulated iNOS and NOSTRIN expressions. TQ exerts its hepatoprotective effect, at least in part, by nitric oxide signaling pathway through modulation of iNOS, eNOS, and NOSTRIN expressions as well as suppression of oxidative stress.

Hesperidin alleviates cisplatin-induced hepatotoxicity in rats without inhibiting its antitumor activity.

BACKGROUND: Hesperidin, a naturally occurring flavonoid, exerts many clinically appreciable effects such as anti-oxidant, anti-allergic and anti-inflammatory actions. The present study aimed to investigate the possible protective effects of multiple doses of hesperidin against cisplatin-induced acute hepatotoxicity in rats. METHODS: Hesperidin (100 or 200mg/kg po) was given to rats one day before cisplatin (7.5mg/kg, ip) injection. All animals were sacrificed 5 days after cisplatin injection and blood samples were collected for determination of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, triglycerides (TG) and total cholesterol levels. Liver samples were used for the determination of malondialdehyde (MDA), glutathione (GSH), total nitrate and nitrite contents. Western blot analysis was used for the assessment of NF-κB and p-Akt expression and histopathological examination was also performed. RESULTS: Results showed that hesperidin significantly reduced cisplatin-induced elevations in serum ALT and AST activities, TG and total cholesterol levels. It also reduced cisplatin-induced oxidative stress by significant reduction in liver MDA and NO content and elevation of GSH content. In addition, hesperidin significantly counteracted cisplatin-induced increased NF-κB expression and decreased p-Akt expression. Histopathological examination revealed that hesperidin greatly protected liver against cisplatin-induced injury. Moreover hesperidin did not inhibit the cytotoxic effect of cisplatin on cancer cells as determined by MTT assay. CONCLUSION: Hesperidin decreased cisplatin-induced functional and histopathological liver damage in a dose-dependent manner without affecting its potential cytotoxic effect.