AUTHOR=Zhou Yuan , Xue Mei , Jiang Yunfei , Zhang Miaomiao , Wang Changming , Wang Xuyang , Yu Guang , Tang Zongxiang TITLE=Beneficial Effects of Quercetin on Microcystin-LR Induced Tight Junction Defects JOURNAL=Frontiers in Pharmacology VOLUME=Volume 12 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.733993 DOI=10.3389/fphar.2021.733993 ISSN=1663-9812 ABSTRACT=Quercetin has numerous functions including antioxidant and anti-inflammatory effects. The beneficial effect of quercetin against microcystin-LR (MC-LR)-induced testicular tight junction defects in vitro and in vivo were investigated. Significant reductions in transepithelial electrical resistance, occludin, and zonula occludens-1(ZO-1) levels were detected in the MC-LR-treated TM4 cells, and quercetin attenuated these effects. Interestingly, quercetin suppressed MC-LR-induced phosphorylation of AKT. It effectively inhibited the accumulation of ROS in cells stimulated by MC-LR. In addition, ROS inhibitors blocked the tight junction damage that is dependent on the AKT signaling pathway induced by MC-LR. In conclusion, our results suggest that alleviates MC-LR-impaired tight junction by suppressing the ROS-regulated activation of the AKT pathway.