[Effects of fosinopril and losartan on the expression of Toll- like receptor 4 in renal tubular epithelia cells].

OBJECTIVE: To determine the mechanism of Toll-like receptor 4(TLR4) in hypertensive renal injury and the protective effect of fosinopril(Fos) and losartan(Los).

METHODS: NRK-52E was incubated into 5 groups: NRK-52E (normal control), NRK-52E+AngII, NRK-52E+AngII+Fos(10(-5) mmol/L),and NRK-52E+AngII+Los(10(-5) mmol/L), NRK-52E +AngII+Fos(10(-5) mmol/L)+Los(10(-5) mmol/L). TLR4-specific RNAi plasmids were stably transfected into NRK-52E. After 24 h, TLR4, IL-6, and TNF-alpha mRNAs were examined by reverse transcription-polymerase chain reaction(RT-PCR). TLR4 proteins were detected by Western blot, NF-kappaB nuclear translocations were tested by immunocytochemistry,and IL-6 and TNF-alpha supernatant levels were tested by enzyme linked immuno-sorbent assay(ELISA).

RESULTS: TLR4, NF-kappaB, IL-6,and TNF-alpha were highly expressed in AngII induced NRK-52E(P<0.01). In NRK-52E that was stably transfected TLR4-special RNAi plamids, TLR4 protein and mRNA expression were obviously inhibited(P<0.05). After stimulation by AngII, the TLR4, IL-6, TNF-alpha levels in the stabe transfection group were increased compared with the normal group(P<0.05). Fos or/and Los down-regulated TLR4, IL-6, and TNF-alpha expressions(P<0.05), but no cooperation was observed.

CONCLUSION: TLR4 may lead to inflammatory reaction in hypertensive renal injury. Fos or/and Los can decrease the expressions of TLR4 and correlate inflammatory factors, which may be part of the renal protective mechanism.