[Discussion on the curative effect and mechanisms of berberine in rats with non-alcoholic fatty liver]

Objective: To observe the curative effects of berberine in rats with high-fat diet induced non-alcoholic fatty liver and to further explore its possible mechanism. Methods: Twenty-six Sprague-Dawley rats (120-160 g) were randomly divided into 3 groups: control group (n = 8), model group (n = 10) and treatment group (n = 8). Rats in the control group were fed with regular diet, and the model group and the treatment group were fed a high-fat diet. At the 12th week, two rats in the in the model group were sacrificed to verify whether model was successful established. Subsequently, treatment group rats were given a gavage of berberine at a dose of 150 mg·kg(-1)·d(-1) for 4 weeks, and the control and the model group rats were given the same dose of normal saline. Rats were sacrificed at week 16th. HE staining was used to observe the changes in the intestinal mucosa of rats. Sudan black B staining was used to observe the fatty changes in liver. Immunohistochemical staining was used to observe the expression level of occludin protein in the intestinal epithelium. A real-time 16S rDNA PCR method was used to measure the number of escherichia coli, bacteroides and faecalibacterium prausnitzii in the feces of rats. Results: Model group had a higher serum levels of endotoxin (0.288 ± 0.045) and tumor necrosis factor (TNF)-α (1.07 ± 0.11) than the control group (0.192 ± 0.049, 0.94 ± 0.07) (P < 0.05). Berberine intervention had significantly reduced endotoxin (0.213 ± 0.025) and TNF-α level (0.93 ± 0.07) (P < 0.05). The expression level of occludin protein was significantly lower in the intestinal mucosa of model group than that of control group (0.166 ± 0.014), and berberine had promoted the expression of occludin protein in intestinal mucosa (0.055 ± 0.009), but the difference was not statistically significant (P > 0.05). At the same time, compared with the model group (7.29 ± 0.47), the number of bacteroidetes in the control group (9.49 ± 0.59) was decreased, while the number of bacteroidetes in the treatment group was increased (9.77 ± 0.87). The number of escherichia coli (6.92 ± 0.77) and faecalibacterium prausnitzii (8.70 ± 0.62) in the model group were increased than control group (5.42 ± 0.63, 9.49 ± 0.59), while the number of escherichia coli (6.34 ± 0.71) and faecalibacterium prausnitzii (9.77 ± 0.87) (P < 0.05) was reduced with the intervention of berberine. Conclusion: Berberine could effectively protect the intestinal barrier function in rats with NAFLD and the possible mechanism of action behind it may be the regulation of intestinal flora.