The role of oxidative stress in DNA damage in pancreatic β cells induced by di-(2-ethylhexyl) phthalate.

Di(2-ethyhexyl) phthalate (DEHP) is commonly used as a plasticizer, which loosely binds to plastic materials and easily leaches out of these products and enters into the environment. Exposure to DEHP can impair pancreatic beta cells (INS-1 cells)function, which is associated with Insulin Resistance (IR) and type 2 diabetes. However, the mechanism of how DEHP leads to Insulin Resistance is unknown. Our results showed that the cell viability of INS-1 cells exposed to DEHP (0-1600 μM) were decreased in a concentration-dependent manner. DEHP caused significant increases of DNA migration and oxidative damage in INS-1 cells. Lysosomal membrane permeability was increased and mitochondrial membrane potential was reduced after INS-1 cells treated with DEHP. DEHP was also shown to induce ROS production and cause GSH depletion in INS-1 cells. DEHP brought a significant decrease in super oxide dismutase (SOD) and led to accumulation of malondialdehyde (MDA) in the INS-1 cells. DEHP increased significantly the expression of P53 and ATM gene of INS-1 cell at high dose levels. Simultaneously, Pyrroloquinoline Quinone (PQQ), an antioxidant, and alcohol were used in the study to determine their effects on DEHP-induced INS-1 cells damage. PQQ could protect the INS-1 cells from the damage induced by DEHP to some extent, while alcohol aggravated the toxic effects of DEHP. These results indicate that DEHP-mediated INS-1 cell dysfunction through a lysosomal-mitochondrial pathway, involving oxidative stress and p53 and ATM activation.