PM2.5 exposure induces renal injury via the activation of the autophagic pathway in rat and HK-2 cell

Abstract

Background Exposure to airborne fine particulate matter (PM2.5) has been declared to be harmful to the human kidney. However, whether activation of the autophagic pathway plays key roles in the nephrotoxicity caused by PM2.5 exposure is still poorly understood. The aim of this study was to explore the mechanism of kidney damage after PM2.5 exposure in vivo and in vitro. Results In the present study, statistically significant alterations in water intake, urine flow rate and mean blood pressure were observed between the PM2.5 group and FA group during the period of PM2.5 exposure. Exposed animals showed severe edema of renal tubular epithelial cells, capillary congestion, reduction of the glomerular urinary space and early pro-fibrotic state. Moreover, significant increases in the levels of early kidney damage markers were observed in the exposed rats and these animals exhibited more apoptosis rate in kidney cells. In addition, PM2.5 exposure resulted in the activation of the autophagic pathway, as evidenced by LC3-I to LC3-II conversion, P62 and beclin-1 activated. All of these effects are in concurrence with the presence of more autophagosomes both in vivo and in vitro after PM2.5 exposure. Conclusions Taken together, our findings indicated that PM2.5-induced renal injury via the activation of the autophagic pathway in renal tubular epithelial cells.