Effect of Total Suspended Particulate Matter in the Air on Inflammation Factors and Apoptotic Markers in Diabetic Rats: The Protective Effect of Insulin and Crocin

Background: The effect of total suspended particulate matter (TSP) was investigated on the expression of inflammatory and apoptotic factors in diabetic rats, and the effect of crocin and insulin was examined on these factors. Methods: Fifty-four adult male wistar rats were divided into nine experimental groups: control group, crocin group (received crocin, 50 mg/kg), diabetic group (received a single dose of alloxan at 120 mg/kg, IP), TSP group (5 mg/kg TSP instilled intratracheally), diabetic-crocin group (received crocin at 50 mg/kg after the induction of diabetes by alloxan (120 mg/kg)), diabetic-insulin group (received regular insulin (5 U/kg), crocin-TSP group (received crocin at 50 mg/kg, IP, and then 5 mg/kg TSP was instilled intratracheally), diabetic-TSP-insulin group (after receiving alloxan (120 mg/kg) and instilling TSP (5 mg/kg, intratracheally), a single dose (5 U/kg) of regular insulin), and diabetic-TSP-crocin group (after receiving alloxan (120 mg/kg) and instilling TSP (5 mg/kg, intratracheally), a single dose of crocin (50 mg/kg, IP)). Quantitative real-time PCR was performed to measure the expression of the mRNAs of apoptotic (Bax and Bcl2) and inflammatory mediators (TNFα, COX2, iNOS/eNOS) in Wistar rats. Results: In diabetic and TSP groups the inflammatory factors and BAX/Bcl2 ratio significantly increased compared to the control group. In diabetic-TSP-insulin and diabetic-TSP-crocin, a significant decrease was observed in the rate of inflammatory factors and BAX/Bcl2 ratio. Conclusions: The results suggested that diabetes and exposure to TSP increase the rate of apoptosis and inflammation, and also demonstrated the anti-apoptotic and anti-inflammation role of insulin and crocin.