The interventional effects of neurotropin on the expression of inflammatory cytokines and Toll-like receptors in LPS-induced microglial cells

Objective To investigate the interventional effect of neurotropin (NTP) on inflammatory response and its underlying mechanisms in lipopolysaccharide (LPS)-induced BV-2 microglial cells. Methods The cell counting kit-8 (CCK-8) assay was used to detect the cell viability. Quantitative real time reverse polymerase chain reaction (qRT-PCR) was performed to measure the mRNA expression of IL-1β, iNOS, TLR2, TLR4, TLR6, and MyD88, while the Western blot was conducted to detect the protein expression levels of TLR4 and MyD88. Results The treatment with various concentrations of LPS (100 ng/ml, 1 000 ng/ml) or NTP (0.001 NU/ml, 0.01 NU/ml, 0.1 NU/ml) for 12 h showed no significant effects on cell viability when compared to thecontrol group (P> 0.05). The treatment with LPS for 12 h upregulated the mRNA expression of inflammatory cytokines (IL-1βand iNOS), Toll-like receptors (TLR2, TLR4, and TLR6) and MyD88, and increased the protein levels of TLR4 and MyD88, when compared to the control group (P< 0.05). Whereas, pretreatment with NTP for 12 h downregulated the expression of IL-1β, iNOS, TLR2, TLR4, TLR6, and MyD88 at mRNA level and decreased the expression of TLR4 and MyD88 at protein level with a significant difference from the LPS (1 000 ng/ml) group (P< 0.05). Conclusions NTP can inhibit the inflammatory response in LPS-induced BV-2 cells and the regulation of Toll-like receptors and its downstream gene might be involved in the process. Key words: Neurotropin; LPS; Microglial cells; Inflammatory cytokines; Toll-like receptors