Tanshinone IIA alleviates lipopolysaccharide-induced acute lung injury by downregulating TRPM7 and pro-inflammatory factors

The study aimed to investigate the role of Tanshinone IIA (Tan IIA) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in its regulation of TRPM7. Wistar male rats were randomly divided into the normal saline (NS), LPS, knockout (KO) + LPS, low-dose Tan IIA (Tan-L), middle-dose Tan IIA (Tan-M), high-dose Tan IIA (Tan-H) and KO + high-dose Tan IIA (KO + Tan-H) groups. The level of tumour necrosis factor- (TNF-alpha), interleukin (IL)-1, IL-6, TRPM7 protein expression, current density-voltage curve and Ca2+ concentration were detected through ELISA, Western blotting, electrophysiological experiment and a calcium-imaging technique, respectively. The rats in the KO + LPS, Tan-L, Tan-M, Tan-H and KO + Tan-H groups all displayed lower levels of TNF-alpha, IL-1 and IL-6 than the LPS group. Rats in the KO + Tan-H group exhibited lower levels of NF-alpha, IL-1 and IL-6 than rats in the Tan-H group. Elevated levels of TRPM7 protein expression in the LPS and Tan groups were detected in comparison with the NS group. However, TRPM7 protein expression in Tan-M and Tan-H groups was notably lower than in that of the LPS group. In comparison with the NS group, the LPS and Tan groups had a greater PIMs cell density and a higher concentration of Ca2+. Contrary results were observed in the KO + LPS, Tan-H and KO + Tan-H groups. Tan IIA decreases calcium influx in PIMs and inhibits pro-inflammatory factors which provide an alleviatory effect in regards to LPS-induced ALI by suppressing TRPM7 expression.