Acta Cirúrgica Brasileira (Jan 2006)
A study of the effects of pinealectomy on intestinal cell proliferation in infant newborn rats
Abstract
PURPOSE: Study the proliferation rate of jejunum and large intestine crypt epithelial cells, in rats pinealectomized immediately after borning. METHODS: Twenty-four male Wistar rats were distributed into two groups: Acute group (n=12) and Chronic group (n=12). Six animals of each group were operated for removal of the pineal gland (pinealectomy-PnX), and other six were controls (sham pinealectomy-C). Animals from acute and chronic group were sacrificed 15 and 90 days after the surgery, respectively. RESULTS: In acute group, pinealectomy of new-born rats has not caused significant alteration in cell proliferation (PnX=58,77?1,77 and C=60,88?1,10 in the descending colon/ PnX=31,56?0,45 and C=31,73?0,47 in the proximal jejunum) and in crypt cell population (PnX=24,92?4,82 and C=23,60?2,48 in the descending colon/ PnX=39,92?3,49 and C=44,32?5,56 in the proximal jejunum). However, in chronic group there was an uprising crypt cell production per crypt in the proximal jejunum (PnX=57,54?2,19 and C=47,19?7,3)and in the descending colon (PnX=37,78?2,22 and C=17,92?2,28). CONCLUSION: As the increase of intestinal crypts epithelial cells in chronic group is a carcinogenesis predetermining factor, the understanding of the interaction between pineal gland and this event has great importance.