Objective To investigate the expression of Toll- like receptor 4( TLR4) in the rat model of nonalcoholic fatty liver disease( NAFLD). Methods A total of 16 specific pathogen- free Sprague- Dawley rats were divided into normal group and NAFLD group,with8 rats in each group,and in the NAFLD group,a rat model was established by high- fat feed. HE staining was used to detect the pathological changes in the liver,enzyme- linked immunosorbent assay was applied to measure the levels of tumor necrosis factorα( TNFα) and interleukin- 1( IL- 1) in serum,and quantitative real- time PCR and immunohistochemical staining were applied to observe the expression of TLR4 signal in the liver. Comparison of continuous data between the two groups was made by t- test. Results In the NAFLD group,typical formation of lipid droplets and vacuoles was observed in hepatocytes,and mononuclear cell infiltration was observed in some hepatocytes. Compared with the normal group,the NAFLD group had significantly higher levels of serum TNFα and IL- 1( t = 7. 94 and 2. 86,respectively; both P < 0. 05) and significantly higher expression of TLR4,myeloid differentiation factor 88,and TNF receptor- associated factor 6( t = 13. 91,30. 71,and 29. 70,respectively; all P < 0. 05). Conclusion Overexpression of TLR4 signal is observed in the NAFLD rat model,which suggests that it is involved in the process of NAFLD inflammation and hepatic fibrosis.
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