Objective: To explore the role of Toll like receptor 4(TLR4) in the asthmatic rat airway smooth muscle cell (ASMCs) proliferation and apoptosis.
Methods: Established rat model of asthma,isolated and cultured rat ASMCs in asthma, using methods of small molecule RNA interference technology and lipofection method, for small molecule RNA-TLR4 transfection, detected proliferation of ASMCs by MIT minim colorimetry, apoptosis of ASMCs by TUNNEL, the expression of TLR4 protein and mRNA were detected by Western blot and RT-PCR in cells.
Results: The proliferation of ASMCs in TNF-alpha group were significantly higher than that in control group and siRNA-TLR4 transfection group and TNF-alpha + siRNA-TLR4 transfection group respectively and the proliferation of ASMCs in siRNA-TLR4 transfction group was lower than that in control group. The apoptosis rate of ASMCs in TNF-alpha group was lower than that in control group, siRNA-TLR4 transfection group and TNF-alpha + siRNA-TLR4 transfection group respectively and the apoptosis rate of ASMCs in siRNA-TLR4 transfection group and TNF-alpha + siRNA-TLR4 transfection group were significantly higher than those in control group. The mRNA and protein expression of TLR4 in control group and TNF-alpha group were significantly higher than those in siRNA-TLR4 transfection group and TNF-alpha + siRNA-TLR4 transfection group. The mRNA and protein expression of TLR4 in TNF-alpha group were significantly higher than those in control group (P < 0.01).
Conclusion: Activation of TLR4 may contribute to asthmatic airway smooth muscle cell proliferation, inhibiting apoptosis and play an important role in airway remodeling in asthma.