Research on the Effect and Mechanism of Betaine on Dimethylnitrosamine Induced Cirrhosis in Rats
Objective To investigate the effect and mechanism of betaine on dimethylnitrosamine (DMN)-induced liver cirrhosis in rats. Methods Forty male Wistar rats were randomly divided into normal group,model group,Yishanfu(141.8 mg·kg-1)group,low-and high-dose(100,400 mg·kg-1)betaine groups,with eight rats in each group. A rat model of liver cirrhosis was replicated by intraperitoneally injected with 0.5％ DMN solution(2 mg·kg-1). Then the corresponding drugs were given orally once a day for two weeks. The activity of alanine aminotransferase(ALT) in serum was detected by biochemical analyzer. The pathological changes of liver tissue were observed by hematoxylin-eosin (HE) staining and Sirius red (SR) staining. The positive expressions of α-SMA,F4/80 and CD68 in liver tissue were determined by immunohistochemistry. The content of hydroxyproline(Hyp)in liver tissue was determined by alkaline hydrolysis method. Western Blot was used to determine the protein expressions of α-SMA,NLRP3,pro-Caspase1 and IL-18. The mRNA expression levels of fibrosis-related and inflammation-related genes in liver tissue were detected by real-time fluorescence quantitative polymerase chain reaction (qPCR). Results Compared with the normal group,the structure of hepatic lobule of the rats in the model group was damaged. Also,the liver cells were swollen and necrotic,with a large amount of inflammatory cell infiltration. Serum ALT level was significantly increased (P<0.01). A large amount of collagen deposition in liver tissue was observed,Hyp content and percentage of collagen positive area were significantly increased(P<0.01). The percentage of positive area of F4/80 and CD68,as well as the mRNA expressions of F4/80,CD68 and TNF-α in liver tissue were significantly increased(P<0.01). Large amounts of α-SMA positive expression were found in fibrous septum of liver tissue. The percentage of positive area and protein expression of α-SMA were obviously increased (P<0.01). The mRNA levels of Acta2,Col1a1,TGF-β1 were significantly up-regulated(P<0.01). Moreover,the protein expression of NLRP3,pro-Caspase1 and IL-18,as well as the mRNA levels of NLRP3,IL-1β,and IL-18 of liver tissue were obviously increased(P<0.01). Compared with the model group,liver tissue and inflammatory cell infiltration in low-and high-dose betaine groups were improved to varying degrees,and serum ALT level in high-dose betaine group was obviously decreased (P<0.05). Collagen deposition in liver tissue of low-and high-dose betaine groups was reduced,Hyp content and percentage of collagen positive area were significantly decreased (P<0.05,P<0.01). The percentage of positive area of F4/80 and CD68,as well as the mRNA expressions of F4/80,CD68 and TNF-α in liver tissue were significantly decreased (P<0.05,P<0.01). The percentage of positive area and protein expression of α-SMA were obviously decreased(P<0.05,P<0.01). The mRNA levels of Acta2,Col1a1,TGF-β1 were significantly down-regulated (P<0.05,P<0.01). The protein expression of NLRP3,pro-Caspase1 and IL-18,as well as the mRNA levels of NLRP3,IL-1β,and IL-18 of liver tissue were obviously decreased(P<0.05,P<0.01). Conclusion Betaine can alleviate inflammatory damage in liver tissue of DMN-induced cirrhotic rats,inhibit the activation of hepatic stellate cells(HSC),and reduce collagen deposition. The mechanism may be related to inhibition of NLRP3 inflammasome signaling pathway.
万方数据
维普
