Lead exposure increases oxidative stress in the gastric mucosa of HCl/ethanol-exposed rats

AIM: To investigate the role of reactive oxygen species in the ulcer-aggravating effect of lead in albino rats. METHODS: Albino Wistar rats were randomly divided into three groups and treated orally with 100 mg/L (low dose) or 5000 mg/L (high dose) of lead acetate for 15 wk. A third group received saline and served as control. At the end of wk 15, colorimetric assays were applied to determine the concentrations of total protein and nitrite, the activities of the oxidative enzymes catalase and superoxide dismutase, and lipid peroxidation in homogenized gastric mucosal samples. RESULTS: Exposure of rats to lead significantly increased the gastric mucosal damage caused by acidified ethanol. Although the basal gastric acid secretory rate was not significantly altered, the maximal response of the stomach to histamine was significantly higher in the lead-exposed animals than in the unexposed control group. Exposure to low and high levels of lead significantly increased gastric lipid peroxidation to 183.2% ± 12.7% and 226.1% ± 6.8% of control values respectively (P < 0.0). On the other hand, lead exposure significantly decreased catalase and superoxide dismutase (SOD) activities and the amount of nitrite in gastric mucosal samples. CONCLUSION: Lead increases the formation of gastric ulcers by interfering with the oxidative metabolism in the stomach.

Intestinal Handling of Glucose in <i>Buccholzia coriacea</i>Treated Male Wistar Rats

Background: Different studies have unveiled the traditional usefulness and clinical potentials of Buchholzia coriacea, a medicinal plant known for its effectiveness in lowering blood glucose. Its role in intestinal glucose uptake was investigated. Materials and methods: Thirty male Wistar rats, weighing between 100 - 120 g were used and randomly assigned into three groups of 5 rats each per experiment. Group 1: control (not treated), groups 2 and 3, were treated with 100 mg/kg (BC100) and 200 mg/kg (BC200) of Buchholzia coriacea orally respectively for 2 weeks. Fasting blood glucose, luminal and in vitro glucose levels of rats were determined by glucose oxidase method using glucometer stripes plus glucose monitoring system (Fine test glucometer(R) ). Luminal electrolytes in the in vitro study were determined by Atomic Absorption Spectrophotometry method. Data were expressed as Mean ± SEM and statistical analysis was by one way ANOVA, and p-values Results: There was no significant change in the fasting blood glucose level (mg/dl) of rats in BC100 (78.00 ± 2.16) and BC200 (76.0 ± 3.57) compared with control (79.50 ± 1.70). There was significant increase in glucose uptake (mg/dl/g tissue) in the in vivo experiments in both the ileum and jejunum of BC100 (23.08 ± 0.18;19.68 ± 0.72) and BC200 (14.50 ± 1.02;20.55 ± 0.45) compared with control (30.40 ± 1.01;35.53 ± 1.45), respectively. The glucose uptake at the mucosa end of distal jejunum in the BC100 (292 ± 3.33) and BC200 (209.30 ± 2.67) decreased significantly compared with control (90.00 ± 1.50). There was a significant decrease in K+ concentration and increase in Na+ concentration at the mucosa end in the BC100 and BC200 compared with control. Conclusion: The study suggests glucose stowing in the intestinal cells in the in vivo study and inhibition of glucose transport from the in vitro study. The roles of alpha-amylase on the activity of this extract are suggested for future studies.

Trivalent Chromium Promotes Healing of Experimental Colitis in Mice by Suppression of Inflammation and Oxidative Stress

Ulcerative colitis (UC) has reactive oxygen species (ROS) and immunologic pathways implicated in its pathogenesis. The search for new therapeutic protocols in managing UC is tailored in suppressing or preventing these pathways. The influence of trivalent chromium (Cr3+), an essential mineral on experimental colitis was investigated. Mice were grouped into 3;group 1 (control) received clean drinking water while groups 2 and 3 received 10 and 100 ppm Cr3+ respectively for 12 weeks through drinking water. After Cr3+ administration, 5 animals per group were sacrificed on day 0. Thereafter, experimental colitis was induced intra-rectally using acetic acid (4%, 0.3mL) and 5 mice per group were subsequently sacrificed on days 3, 7 and 14. Blood and colonic tissues were obtained and processed appropriately. Blood Cr3+ level, haematological variables, gross and microscopic colitis scores, colonic myeloperoxidase (MPO), Superoxide Dismutase (SOD) and malondialdehyde (MDA) levels were determined using standard methods. Colon cytokine mRNA genes were quantified using real-time PCR. There was a significant decrease in colon gross and histology scores on days 3 and 7 in chromium treated compared with control. The MPO and MDA in chromium groups reduced significantly compared with control while SOD activities increased significantly in Cr3+ groups compared with control. Total RNA increased in chromium groups compared with control on day 3 post-colitis. There was up-regulation of IL-10, down-regulation of TNF-α and IFN-λ in chromium administered groups compared with control. Chromium enhanced healing of colitis by suppression of ROS, inflammation and promotion of antioxidant activities.

Extended Fasting Durations Delayed Gastric Emptying and Colonic Motility in Normal Male Rats

Background: Previous studies on fasting and gastrointestinal motility were reported with information lacking concerning prolonged continuous fasting and gastrointestinal motility. This study investigated the effect of prolonged fasting duration on gastrointestinal motility. Methods: Forty-five (45) male Wistar rats, with body weights between 180 - 200 g were used. They were randomly assigned into three (3) groups. Group1: control (rats fasted for 18 h—common duration of fasting for motility studies), groups 2 and 3 fasted for 48 and 72 h respectively. Five (5) rats per experiment and per group were considered. Blood glucose was determined by glucose oxidase method, gastric emptying was assessed by hydrated carbohydrate meal, intestinal motility by charcoal meal, and colonic motility was assessed using bead test. Data were reported in Mean ± SEM and analyzed with one-way ANOVA. Differences in results were considered significant at p ≤ 0.05. Results: There was no significant change in the blood glucose level (mmol/L) of rats in the 48 h group (2.94 ± 0.35) and 72 h group (3.20 ± 0.32) as compared with the control (3.62 ± 0.19). There was a significant decrease in the rate of gastric emptying (g) in the 72 h group (0.20 ± 0.08) compared with the control (0.64 ± 0.16). The intestinal transit (cm) in the 48 h group (67.54 ± 6.15) and 72 h group (72.10 ± 7.60) increased significantly when compared with the control (42.14 ± 3.14). There was a significant decrease in the colonic motility time (Sec.) in the 48 h group (2707 ± 864.1) and 72 h group (6363 ± 968.1) when compared with the control (263.8 ± 64.26). Conclusion: Extended fasting durations decrease the rate of gastric emptying and colonic motility. It suggests that extended fasting durations could be beneficial in intestinal spasms or where the gut is required to relax.