Effect of sulfur dioxide exposure on histopathology and morphometry of pancreatic islet cells and glycemic indices in Wistar rats.

Sulfur dioxide (SO) is a ubiquitous air pollutant. Recent studies suggest that SO is a momentous risk factor for diabetes mellitus (DM). The present investigation aimed to evaluate the effects of SO exposure on histopathology and morphometry of pancreatic islet cells and serum glycemic indices in rats. Sixteen male Wistar rats were divided equally into SO and control groups. SO group was exposed to 10 parts per million (ppm) SO for 5 weeks (6 days a week, 3 h/day) and control group to filtered air for the same time as SO group. Blood serums were collected and pancreatic tissue isolated. Glycemic indices were measured. Pathological and morphometric changes were studied in the pancreatic tissues. Exposure to SO caused a significant increase in blood glucose but did not significantly change insulin and HbA1c serum levels and HOMA-IR. There were significant differences in vascular congestion (p= 0.02) and insulitis (p= 0.04) between the groups. SO inhalation significantly reduced beta cell number and beta-alpha cell ratio compared with the control group (p=0.03 and p<0.0001, respectively). These findings suggest that SO exposure damages pancreatic tissue which subsequently influences either the incidence of DM or the trend of diabetic complications.