Comparative analysis of islet density in rat pancreas lobes: A histological and immunohistochemical study

Comparative analysis of pancreatic islet density in rat pancreas lobes was investigated in total six adult Sprague Dawley rats. The pancreas from each rat was systematically divided into four anatomical lobes: gastric, splenic, upper duodenal, and lower duodenal. Tissue samples were processed using standard histological and immunohistochemical techniques. Serial sections were obtained from each lobe at three levels, 100 μm apart, with two sections cut at each level. One section per level was stained with hematoxylin and eosin (H&E), and the other with insulin immunohistochemistry. Pancreatic islets were counted in 10 non-overlapping low-power fields from each lobe in the H&E-stained sections. In the immunohistochemically stained sections, the largest islet was identified, captured at 10x magnification, and analysed with Qu Path software to determine the percentage of positive and negative staining. The splenic lobe exhibited the highest density of pancreatic islets in both H&E staining and immunohistochemistry. The density of islets decreased sequentially in the upper duodenal, gastric and lower duodenal lobes. The pancreatic duct was consistently observed in the upper duodenal lobe of all animals. The area of positive insulin staining was found to vary across different lobes of the rat pancreas, with the splenic lobe exhibiting the highest area of positive insulin staining and the gastric lobe showing the lowest.