Effects of agomelatine on rat liver regeneration following partial hepatectomy.

Primary or metastatic hepatic malignancies are common. Partial hepatectomy (PH) is the primary treatment for both benign and malignant hepatic neoplasms; it also is used for living donor liver transplantation. The regenerative potential of the liver after PH is 70-80% in humans. We investigated the protective and therapeutic effects of agomelatine (AGM) on rat liver regeneration following PH. We used 32 rats distributed equally into four groups: group 1, sham control; group 2, PH group; group 3, administered 20 mg/kg AGM orally once/day for 7 days following PH; group 4, administered 20 mg/kg AGM orally once/day 3 days before and 7 days following PH for 10 days. Liver samples were analyzed for antioxidants and free radicals. Tissue samples were processed and stained with hematoxylin and eosin to assess histopathological status and stained immunohistochemically for Ki-67. We found that PH reduced antioxidant enzymes and increased tissue reactive oxygen species, whereas AGM treatment had the opposite effect on these parameters. Our biochemical and histopathological findings were consistent. PH caused sinusoid congestion and dilation. Intensity of Ki-67 immunostaining of hepatocytes was increased in group 2, whereas these were reduced in group 4. Intensity of Ki-67 immunostaining of hepatocytes was increased in group 2, whereas it was reduced in the group 4 compared to group 1. We found that AGM was hepatoprotective following PH due to its antioxidant and free radical scavenger properties.

The protective effects of apocynin on ionizing radiation-induced intestinal damage in rats.

BACKGROUND AND AIMS: Radiation colitis typically emerges during radiotherapy of intra-abdominal malignancies. While the underlying mechanism remains unclear, it is considered that free oxygen radicals act like cellular mediators to cause colonic damage. Apocynin (APO) prevents oxidative stress and apoptotic cell death by inhibiting NADPH oxidase, and preventing the formation of free oxygen radicals. The aim of the present study was to investigate the protective effect of APO, a strong antioxidant and antiinflammatory agent, on radiation induced colonic oxidative damage in rats. MATERIALS AND METHODS: Rats were randomly divided into four groups (n = 8/group). Group I (control group); Group II (Group RAD) received a single dose of 800 cGy ionizing radiation to the whole abdomen with a linear accelerator (LINAC); Group III (Group APO) received a single dose of 20 mg/kg of APO intraperitoneally for five days; Group IV (Group APO+RAD) received APO for five days before radiation exposure (similar to Group III), (similar to Group II). RESULTS: APO treatment prior to radiation led to protection in the biochemical and histopathological parameters. CONCLUSIONS: Our study shows that APO treatment before radiation improves radiation induced colonic injury in rats, by decreasing oxidative stress and apoptosis.

Dose-dependent protective effect of ivabradine against ischemia-reperfusion-induced renal injury in rats.

BACKGROUND/AIMS: This study was designed to investigate the dose-dependent protective effect of ivabradine, a specific inhibitor of the cardiac sinoatrial node, on renal ischemia-reperfusion (I/R) injury in rats. METHODS: Rats were divided into six groups: group 1, control; group 2, I/R (60 min ischemia followed by 24 h reperfusion); groups 3 and 4, 0.6-6 mg/kg ivabradine; and groups 5 and 6, sham+0.6-6 mg/kg ivabradine. At the end of the study, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase contents were assayed in the kidney tissues; serum blood levels of urea nitrogen (BUN), creatinine (Cr) and albumin also were determined. RESULTS: Tissue MDA levels were found to be significantly higher in the I/R group, whereas SOD and CAT levels were lower when compared to the control group. Ivabradine (0.6 mg/kg) treatment reduced the MDA levels and elevated the SOD and CAT enzyme activity. Treatment with a dose of 6 mg/kg ivabradine further increased MDA levels and did not ameliorate SOD or CAT activities. Serum levels of BUN and Cr were significantly higher in the I/R group. I/R+0.6 mg ivabradine reduced the elevated BUN and Cr levels. CONCLUSION: This study indicates that ivabradine exerts a dose-dependent response beyond heart rate reduction against renal I/R injury.

The effect of extracts from ginger rhizome on inflammatory mediator production.

Compounds from rhizomes of Zingiber officinale, commonly called ginger, have been purported to have anti-inflammatory actions. We have used an in vitro test system to test the anti-inflammatory activity of compounds isolated from ginger rhizome. U937 cells were differentiated and exposed to lipopolysaccharide (LPS) from Escherichia coli (1 microg/ml) in the presence or absence of organic extracts or standard compounds found in ginger (6-, 8-, 10-gingerol or 6-shogaol) for 24 h. Supernatants were collected and analyzed for the production of prostaglandin E(2) (PGE(2)) and tumor necrosis factor alpha (TNF-alpha) by standard ELISA assays. Predominant compounds in the organic extracts were identified as 6-, 8- 10-gingerols and 6-, 8-, 10-shogaols. Organic extracts or standards containing gingerols were not cytotoxic, while extracts or standards containing predominantly shogaols were cytotoxic at concentrations above 20 microg/ml. Crude organic extracts of ginger were capable of inhibiting LPS induced PGE(2) (IC(50)<0.1 microg/ml) production. However, extracts were not nearly as effective at inhibiting TNF-alpha (IC(50)>30 microg/ml). Thirty three fractions and subfractions, prepared by column chromatography, were analyzed for bioactivity. Extracts containing either predominantly gingerols or shogaols (identified by HPLC) were both highly active at inhibiting LPS-induced PGE(2) production (IC(50)<0.1 microg/ml), while extracts that contained unknown compounds were less effective (IC(50)<3.2 microg/ml). Extracts or standards containing predominantly gingerols were capable of inhibiting LPS-induced COX-2 expression while shogaol containing extracts had no effect on COX-2 expression. These data demonstrate that compounds found in ginger are capable of inhibiting PGE(2) production and that the compounds may act at several sites.