Endotoxin-Mediated Intestinal Damage: Protective Effect of Capsaicin in the Rat

Background: Endotoxin provokes the disruption of intestinal mucosal architecture. To investigate whether afferent fibers of the enteric nervous system are involved in this damage, we have used capsaicin to induce a selective, long-lasting degeneration of these fibers in the rat. Methods: The rats were divided in two groups, receiving subcutaneously either capsaicin or its vehicle. After 10 days the rats from each group were injected with nonlethal doses of endotoxin or with saline. The next day all the animals were killed, and the jejunum and ascending colon were collected for light and scanning electron microscopy analysis; morphometric analysis of jejunal villus height was also performed. Results: The rats receiving endotoxin but not pretreated with capsaicin had severe morphologic alterations and a significant reduction in villus height. In contrast, the rats pretreated with capsaicin and then with endotoxin showed a preserved mucosa with normal mean villus height. Conclusions: Capsaicin pretreatment is able to prevent endotoxin-induced damage of intestinal mucosa; this result seems to indicate that afferent fibers of the enteric nervous system are involved in the pathogenesis of this damage.