Alterations in plasma and erythrocyte membrane fatty acid composition following exposure to toxic copper level affect membrane deformability and fluidity in female wistar rats.

BACKGROUND: Deformability and fluidity function of the red blood cell membrane are properties defined by the lipid composition. Toxic copper level induces membrane lipid peroxidation which could cause membrane instability. This study therefore investigated the effect of exposure to toxic copper level for 30 days on red blood cell membrane deformability and fluidity in female Wistar rats. METHODS: Twelve (12) female Wistar rats (160 ± 10 g) were randomly grouped (n = 6) into control (given 0.1 ml distilled water p.o.) and copper-toxic (100 mg/kg Copper Sulphate, p.o.), and treated for 30 days. Plasma obtained and RBC membrane prepared from blood collected over EDTA post-treatment were assayed for total cholesterol (TC), phospholipids and fatty acid profile using spectrophotometry and Gas chromatography while heparinized blood was subjected to fragility test. Data were analyzed using student T-test for statistical significance at p < 0.05. RESULTS AND CONCLUSION: Plasma TC increased by 4.33% while RBC membrane TC decreased by 20.32% in copper-toxic group compared to control. Compared to control, excess copper significantly increased membrane phospholipids level (0.72 ± 0.01 vs 0.59 ± 0.04 mg/dL) but reduced membrane cholesterol/phospholipid ratio (46.61 ± 4.72 vs 72.66 ± 6.47) and stability (by 23.53%). Number of cis- and saturated fatty acids increased in copper-treated plasma and RBC membrane compared to control. Exposure to toxic copper level alters erythrocyte membrane fluidity and deformability by disrupting membrane lipid composition, saturation, bond configuration in phospholipids and permeability.

Exposure to ultraviolet radiation during pregnancy influences offspring immune and inflammatory responses in Wistar-strain rats.

OBJECTIVE: During pregnancy, maternal exposure to ultraviolet radiation (UVR) has been linked to altered offspring immune and health status. This study was therefore designed to investigate some markers of immune response in the offspring of pregnant Wistar rats exposed to UVR at various points of gestation. METHODS: Thirty pregnant rats were divided into 6 groups (n=5) as follows; group I, control, consisting of pregnant rats unexposed to UVR. Animals in groups II, III, IV, V and VI were exposed to UVR for one hour daily, on gestational days 1-7,8-14,15-21,1-14 and 1-21, respectively. Animals were allowed to come to term and offspring birth weight was taken. On postnatal Day 10, weight of each offspring was taken again. Thereafter, blood samples were collected from each offspring per group and evaluated for total protein, albumin, globulin, C-reactive protein, interleukin-1ß, and complement component protein-3 (C3). Offspring hepatic samples were evaluated using standard histological techniques. RESULTS: Offspring birthweight increased (p<0.05), while weight gain on postnatal day 10 reduced in all experimental groups compared to controls. No significant differences were observed for offspring total protein, albumin, and C3 levels across all groups. Globulin increased (p<0.05) only in group VI, while C-reactive protein increased (p<0.05) in all experimental groups, except group III, compared to controls. Interleukin-1ß in groups II, III, V and VI increased significantly compared to controls. Offspring hepatic samples exhibited hepatocellular degeneration and necrosis that was independent of gestational stage of maternal exposure to UVR. CONCLUSIONS: Maternal exposure to ultraviolet radiation during gestation in Wistar rats activates offspring immune and inflammatory responses.

Intermittent exposure to green and white light-at-night activates hepatic glycogenolytic and gluconeogenetic activities in male Wistar rats.

OBJECTIVES: Exposure to light-at-night (LAN) has been reported to impair blood glucose regulation. The liver modulates blood glucose through mechanisms influenced by several factors that include peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α) and glucose-6-phosphatase (G6Pase). This study investigated the effect of intermittent exposure to green and white LAN on some hepatic glucose regulatory factors in male Wistar rats. METHODS: Animals were divided into three equal groups. Group I (control) was exposed to normal housing conditions. Groups II and III were each daily exposed to either green or white LAN for 2 h (7-9 pm) for 14 days. Body weight and blood glucose was monitored on days 0, 7, and 14. Thereafter, retro-orbital sinus blood was obtained after light thiopental anaesthesia and serum insulin was determined. Liver samples were also obtained and evaluated for glycogen, PGC-1α, and G6Pase activity. Insulin resistance was estimated using the HOMA-IR equation. RESULTS: Body weight and blood glucose on days 7 and 14 increased in groups II and III compared to control. Hepatic PGC-1α and G6Pase increased in group II (2.33 ± 0.31; 2.07 ± 0.22) and III (2.31 ± 0.20; 0.98 ± 0.23) compared to control (1.73 ± 0.21; 0.47 ± 0.11). Hepatic glycogen was 71.8 and 82.4% reduced in groups II and III compared to control. Insulin in group II increased (63.6%) whiles group III values reduced (27.3%) compared to control. Insulin resistance increased in group II (0.29 ± 0.09) compared to control (0.12 ± 0.03) and group III (0.11 ± 0.03), respectively. CONCLUSIONS: Exposure to 2 h green and white LAN in the early dark phase increases hepatic glycogenolysis and gluconeogenetic activities resulting in increased blood glucose. In male Wistar rats, exposure to green but not white LAN may predispose to insulin resistance.

Selenium Supplementation Increases Hepatic Glucose-6-Phosphatase and Peroxisome Proliferator Activated Receptor Gamma Coactivator-1α Activity in Male Wistar Rats.

Increased selenium supplementation has been implicated in diabetes mellitus via peroxisome-proliferator-activated-receptor-gamma-coactivator-1-alpha (PGC-1α) associated pathways. This study was designed to investigate the effect of selenium supplementation on PGC-1α and glucose-6-phosphatase (G6Pase) as well its likely hepato toxicity in male Wistar rats. Animals were randomly divided into 3 groups (n=10/group) and treated orally with water (0.2ml - group 1) or selenium (25µg/day -group 2; 50µg/day - group 3) for 28 and 56days, respectively. Thereafter, blood samples were collected and estimated for glucose, alkaline-phosphate (ALP), gamma-glutamyltransferase (GGT) and aspartate-aminotransferase (AST). Liver homogenates were analyzed for PGC-1α and G6Pase activity. Significant dose-dependent increases in blood glucose, hepatic PGC-1α and G6Pase activities were observed on days 28 and 56 in selenium groups compared to group 1. Serum GGT activity increased in both selenium groups on day 28 however, on day 56 values in group 2 were reduced and increased in group 3, respectively. Compared to control ALP reduced in selenium groups while AST was not significantly different. This study suggests that selenium supplementation increases hepatic peroxisome-proliferator-activated-receptor-gamma-coactivator-1α and glucose-6-phosphatase activity leading to a likely increase in hepatic glucose output. It also shows that though selenium supplementation at the doses used maybe nontoxic to hepatocytes, it may however exert potential toxicity on the biliary tract.