An immunohistochemical study of chromogranin A and Sp-1 immunoreactive cells in the gastrointestinal tract of ovariectomized rats

ABSTRACT

The changes on the regional distributions and frequencies of two types of chromogranin, chromogranin A (CGA) and bovine Sp-1 chromogranin (BCG)-immunoreactive (IR)cells in gastrointestinal (GI)tract of osteoporotic Sprague-Dawley rat induced by ovariectomy were studied by immunohistochemical methods. The experimental animals were divided into two groups, one is non-ovariectomized group (Sham)and the other is ovariectomized group (OVX). Samples were collected from each part of GI tract at 10th week after ovariectomy or sham operation. CGA-IR cells were restricted to the stomach regions with various frequencies regardless of ovariectomy except for the fundus of OVX in which no cells were detected. In addition, BCG-IR cells were also restricted to the pylorus and duodenum regardless of ovariectomy. A significantly decrease of CGA IR cells was detected in OVX compared to that of Sham in both fundus and pylorus, and BCG-IR cells were also significantly decreased in the duodenum(p<0. 05). However, in the pylorus, BCG-IR cells in OVX showed similar frequency compared to that of Sham. In conclusion, the abnormality in density of chromogranin, a generally used GI endocrine cell marker, detected in this study may contribute to the development of GI symptoms in osteoporosis such as impairments of calcium and some lipids, frequently encountered in patients with postmenopausal osteoporosis.