Effects of small bowel exclusion on intestinal myoelectrical activity pattern: comparison between innervated and denervated (transplanted) Thiry-Vella loops in rats.

Small bowel transplantation (SBT) leads to several changes in normal intestinal physiology with special reference to lymphatic disruption and graft denervation. Intestinal myoelectrical activity (MA) has been studied in different conditions, but little is known about MA in excluded bowel segments without the influence of nutrients. We performed this study to evaluate the effects of bowel exclusion on MA pattern. Fifteen Wistar rats were divided into two groups: five were used as donors and five as recipients for SBT; the remaining five underwent isolation of a jejunal segment as Thiry-Vella loop (TVL). On the 20th postoperative day, four bipolar electrodes were implanted in the small bowel of each rat: proximally and distally on the transplanted and the native intestine (SBT group); proximally and distally on the TVL and across the jejunal anastomosis (TVL group). On the 30th postoperative day, MA was recorded for 30 min after a 12 h fast. MA pattern was not altered by the exclusion of innervated jejunal segments (TVLs) with maintenance of high amplitude and migrating myoelectric complex (MMC) occurrence independent of MA in the continuity bowel. The characteristic regular spiking activity was not observed in transplanted grafts and MA analysis showed slow waves containing superimposed irregular spiking activity.

Metabolic and ultrastructural effects of cyclosporin A on pancreatic islets.

We investigated the effect of different doses of cyclosporin A (CyA) on glucose and insulin levels, as well as its residual effects on pancreatic islets ultrastructure after discontinuation of the drug. We studied four groups of Wistar rats. One control- (n = 5) and three experimental groups, n = 10 each, were treated with different doses of CyA i.m. for 14 days: group I, 5 mg/Kg; group II, 15 mg/Kg; and group III, 25 mg/Kg. Five animals of each group were sacrificed after 14 days, and the remaining five after 21 days to assess residual CyA effects. On the day of sacrifice, the rats underwent maltose absorption test, and glucose and insulin levels were measured. Pancreatic biopsies were obtained on day 21 to evaluate islets ultrastructure by electron microscopy. As a result, statistically significant, dose dependent (P < 0.05) increases in glucose and insulin levels were observed in CyA-treated groups. Groups II and III showed insulin levels significantly higher after fasting (P < 0.05) on day 14 comparing to the controls, while in groups I and II values returned to normal after CyA discontinuation. Group III showed persistently increased insulin levels on day 21. Pancreatic ultrastructural changes were observed only in group III. We can conclude that CyA effects on glucose and insulin levels were temporary and reversible at low doses. Ultrastructural changes in the pancreatic islets may occur with high doses of CyA.