Gastrointestinal effects of ivermectin treatment in rats infected with Strongyloides venezuelensis.

We aimed to evaluate the effects of ivermectin treatment on gastrointestinal morphology and function after Strongyloides venezuelensis infection. Male rats composed Control (C), Parasitized (Sv), Ivermectin (IVM) and Parasitized and treated with Ivermectin (Sv/IVM) groups. IVM and Sv/IVM groups were subdivided according to IVM: single dose of 200 µg/kg (IVM1 and Sv/IVM1) or three repeated doses of 200 µg/kg at 24 h intervals (IVM3 and Sv/IVM3). First dose of IVM was administered after peak of infection. Eggs per gram (EPG), mean gastric emptying time (MGET), mean cecum arrival time (MCAT) and mean small intestinal transit time (MSITT) were evaluated. Measurements were performed before drug and at peak of infection, first day post peak of infection and 30 days post infection. Same time intervals were simulated for uninfected animals. Number of recovered worms and intestinal morphometry were also rated. Data were analyzed by ANOVA and correlated by Dunnett and Pearson (p < 0.05). Sv/IVM1 and Sv/IVM3 showed reduction of EPG and worms, although only group SV/IVM3 eradicate them. Hastened gastric emptying and slowed intestinal transit provoked by S. venezuelensis infection can be reverted by a single administration of IVM after peak of infection, even without total parasite elimination. Although three consecutive doses of IVM were more efficient to eradicate the parasite, drug administration impaired gastrointestinal function and morphology. IVM alone affected gastrointestinal parameters in uninfected animals for prolonged periods, especially in high doses. In control, there were strong negative correlations between MSITT and muscle layers. Strongyloides venezuelensis infection abolishes such correlations. Longitudinal muscle was thinner in IVM3 and Sv/IVM3 groups and circular thicker in Sv group. Revisiting the action of traditional drugs broadens knowledge in the parasite-host interface and may result in the development of more accurate therapeutic strategies.

Mild diabetes: long-term effects on gastric motility evaluated in rats.

Moderate hyperglycaemic levels seem to be related to abnormal gastric motility in diabetes mellitus. However, experimental models designed to evaluate the relationship between motility and diabetes over time are not yet well established. Our objective was to investigate the long-term effects of mild diabetes on gastric motility in rats. Newborn male rats received streptozotocin (mild diabetes groups - MD) or vehicle (control groups - C), and both groups were evaluated after 3 (C3 and MD3) and 6 months (C6 and MD6) postinduction. Mild diabetic animals (MD3 and MD6) showed moderately elevated blood glucose and decreased insulin levels compared with control (C3 and C6). Insulin secretion was enhanced in MD6 compared with MD3, most likely due to partial ß-cell regeneration indicated by HOMA-ß. In HOMA-IR, it was noticed that MD6 animals had impaired insulin response compared with MD3. Gastric emptying was faster, amplitude of contraction was stronger in MD6 compared with MD3, and in both groups, the differences were significant when compared with control animals. A significant abnormal rhythmic index was calculated for the mild diabetic groups, despite unchanged mean frequency of contraction. In conclusion, despite increased insulin levels over time, constant levels of moderate hyperglycaemia are also related to abnormal gastric motility and impairment of gastric function.