Effects of Exogenous Ghrelin on the Tissue Structure and Somato-Statin Secretion in the Pancreas of African Ostrich Chicks

Abstract

This study aimed to investigate the effect of exogenous ghrelin on pancreatic growth and development in African ostrich chicks. Sixteen 40-day-old African ostrich chicks (male or female) were randomly divided into four groups and injected intravenously metatarsal vein with saline (control) or ghrelin (10, 50, and 100 µg/kg) for 6 days. Body and pancreas weight were determined, structural characteristics were observed using HE staining, somatostatin-immunopositive cells were detected using immunohistochemistry. The results were as follows: 1. The 50 and 100 µg/kg groups showed lower relative pancreas weight than the control group (P < 0.05). 2.The islet area per unit area of the pancreas was higher in the 10, 50, and 100 µg/kg groups than in the control group (P < 0.05). The number of islets per unit area of the pancreas was lower in the 10 µg/kg group than in the control (P < 0.05) and slightly higher in the 50 and 100 µg/kg groups than in the control (P > 0.05. Moreover, compared with the control, the islet cells in treatment groups were loosely arranged and showed reduced cytoplasm. In the exocrine pancreas, the volume of acinar cells in the 10, 50, and 100 µg/kg groups all decreased to varying degrees. 3. Somatostatin immunopositive cells were mainly located around the periphery of the islets and sporadically distributed in the center. The density of the somatostatin immunopositive cells in the 10, 50, and 100 µg/kg groups was higher than that in the control (P < 0.05). These findings suggest that exogenous ghrelin increases the area and number of islets and number of somatostatin immunopositive cells but reduces relative pancreas weight and effects the morphological and structural development of the pancreas, which may inhibit the pancreatic growth and development in African ostrich chicks.