Research On The Protective Effect Of Crocin On Renal Tubular Epithelial Cell Against Injury And Oxidative Stress Induced By High Level Of Glucose

ObjectiveTo investigate the protective effect of crocin on human renal tubular epithelial cells(HK-2)induced by high level of glucose.And investigate its related molecular mechanism.Methods1.The human renal tubular epithelial cell line(HK-2)was divided into high glucose groups(15,25,40 m M D-glucose)and a control(5.6 m M)group.After pretreatment with crocin,they were exposed to the corresponding D-glucose environment.The changes in cell viability,apoptosis rate,oxidative stress and cell inflammation were observed at 24,48,and72 hours.Then q RT-PCR and Western boltting were used to measure the m RNA and protein expression of Nrf2 and its downstream genes HO-1 and NQO1.2.The HK-2 was divided into stable high glucose(30 m M)group,acute fluctutation glucose(5.6 m M-30 m M alternating)group,and control(5.6 m M)group.The cell viability,apoptotic rate,oxidative stress and TNFα,IL-1β and IL-6 expression were evaluated after 72 hours.Results1.In the present study,we demonstrate that hyperglycemia reduced cell viability in a concentration-and time-dependent manner,which could be attenuated by crocin treatment.q RT-PCR showed elevated m RNA expression of Nrf2 and two downstream genes of Nrf2,HO-1 and NQO1.Western blotting showed that crocin increased protein expression of Nrf2,SIRT1 and p-Akt.Crocin also suppressed high glucose-induced oxidative stress by decreasing MDA and increasing SOD levels.Inhibition of Nrf2,SIRT1 and PI3 K / Akt with si RNA could attenuate the effect of crocin.2.Compared with the stable high glucose group,the acute ambient glucose fluctuations significantly reduced HK-2 cell viability and increased apoptosis.ELISA showed that the expression of TNFα,IL-1β and IL-6 in the acute glucose fluctuations group was significantly higher than that in the stable high glucose group.The oxidative stress test showed that the MDA level in the intermittent high glucose group was significantly higher than that in the stable high glucose group,but there was no statistical difference in SOD levels.Conclusion1.Hyperglycemia induces oxidative stress and inflammation of renal tubular epithelial cells,in which resulting decreased cell viability and induced apoptosis.The cell injury caused by acute glucose fluctuations is severer than the one induced by stable high glucose.The reason for the above phenomenon may be attributed to more elevated oxidative stress and inflammatory effects.2.We demonstrate that crocin protects renal tubular epithelial cells against high glucose-induced injury by the activation of SIRT1-Nrf2 pathway.