Morphologycal, morphometrical and histochemical analysis of the large intestine of rabbits intoxicated with Solanum glaucophyllum (duraznillo blanco)

ZANUZZI CN; BARBEITO CG; ORTIZ ML; FONTANA PA; PORTIANSKY EL; GIMENO EJ.

Paraiba. Brasil.

Simposio; 8 International Symposium on poisonous plants; 2009

Solanum glaucophyllum (Sg) is a toxic plant that induces systemic ruminant’s intoxication due to its high levels of Vitamin D. In the intestine vitamin D contributes to mineral homeostasis, but also regulates the epithelial cellular kinetic and maintain the epithelial barrier integrity. Since few studies have described cell differentiation changes in plant-induced hypervitaminosis D in domestic animals, we analysed the morphological and morphometrical modifications occurring in the colon and rectum of rabbits intoxicated with Sg and the changes in the carbohydrate expression as a cell differentiation indicator.   Three months-old New Zealand male rabbits were intoxicated with a dose of 125mg/Kg/day of Sg, twice a week, during 15 (I1515) or 30 (I3030) days. Animals intoxicated during 15 days but sacrificed after 45 days were considered a “possibly recovered group” (PRG). Two nutritionally restricted groups (NSG), one restricted during 15 days and euthanatized (NSG1515), and the other restricted 15 days but sacrificed after 30 days (NSG1530) were also included. Clinically normal animals were used as controls. Sections from colon and rectum were stained with haematoxylin and eosin, PAS, Alcian Blue or lectin-histochemically studied using the following biotinylated lectins: WGA, Con-A, DBA, SBA, PNA, RCA-1 and UEA-1. Crypts area, length, width and perimeter as well as intestinal wall and layers thicknesses were measured using an image analysis program. The lamina propria and submucosa of colon and rectum of both intoxicated groups appeared hypercellular, oedematous, with lymphangiectasia extended up to the muscular layer. Even though a slight increase in colonic crypts width and a reduction of their length in some intoxicated animals was observed the morphometric analysis revealed that no significant differences were observed between control, intoxicated and NSG groups. However, all the crypts related parameters significantly increased in PRG. Neither colonic wall nor muscular layer thickness varied among the groups. No significant differences among groups were observed for the rectal crypts lengths, but the mucosa and submucosa layers were thinner in the I1515 group. No histochemical changes on the glycocalix and mucin composition were found using PAS or AB techniques. Nevertheless, the lectinhistochemical study revealed a decrease in the DBA binding pattern in both determinations of intoxicated animals. This study provides evidence about histopathologycal and histochemical changes observed in intestines exposed to Sg intoxication. The modifications on the glycosilation pattern found contribute to a possible role of vitmamin D in the regulation of this process.