[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.

[Effect of curcumin on intestinal mucosal mechanical barrier in rats with non-alcoholic fatty liver disease].

Objective: To investigate the effect of curcumin on intestinal mucosal mechanical barrier in rats with non-alcoholic fatty liver disease. Methods: A total of 30 male Sprague-Dawley rats were equally divided into normal control group, model group, and curcumin intervention group. The rats in the model group and the curcumin intervention group were given high-fat feed for 16 weeks, and those in the curcumin intervention group were given curcumin 200 mg/kg/day by gavage once a day after 8 weeks of high-fat feeding. The rats were sacrificed at the end of week 16. A light microscope was used to observe pathological changes in the liver, an electron microscope was used to observe the tight junction of the intestinal mucosa, an automatic biochemical analyzer was used to measure the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), chromogenic substrate Limulus amebocyte lysate assay was used to measure plasma lipopolysaccharide (LPS) level, spectrophotometric method was used to measure the activity of serum diamine oxidase, ELISA was used to measure the serum level of tumor necrosis factor-α (TNFα), and immunohistochemistry was used to measure the expression of the tight junction protein occludin. One-way ANOVA test and SNK-q test were used for statistical analysis. Results: Under the light microscope, the control group had no hepatocyte steatosis, the model group had significant hepatocyte steatosis and inflammatory cell infiltration, and the curcumin intervention group had reduced hepatocyte steatosis and inflammatory cell infiltration. Under the electron microscope, the control group had a clear and complete structure of the tight junction of the intestinal mucosa and normal structures of mitochondria and endoplasmic reticulum; in the model group, the structure of the tight junction of the intestinal mucosa was destroyed, the intercellular space was widened, the desmosomes had a loose structure, there was edema in some mitochondria, and the endoplasmic reticulum was dilated; the curcumin intervention group had improvements in the structure of tight junction of the intestinal mucosa, intercellular space, edema in the mitochondria, and dilation of the endoplasmic reticulum. Compared with the control group, the model group had significant increases in the serum levels of AST, ALT, DAO, TNFα, and LPS (q = -15.918, -14.402, -33.700, -8.944, and -10.832, P < 0.05); compared with the model group, the curcumin intervention group had significant reductions in the serum levels of AST, ALT, DAO, TNFα, and LPS (q = 10.457, 7.752, 18.802, 5.202, and 4.279, P < 0.05). In the control group, occludin showed a linear distribution along the top of small intestinal mucosal epithelial cells. The model group had a significant reduction in positive staining compared with the control group, and the curcumin intervention group had a significant increase in positive staining compared with the model group. The relative expression of occludin was 0.29±0.03 in the control group, 0.12±0.02 in the model group, and 0.21±0.02 in the curcumin intervention group (P < 0.05). Conclusion: Intestinal mucosal mechanical barrier is impaired in rats with NAFLD. Curcumin can reduce such damage, and its mechanism of action may be related to up-regulating the expression of occludin in the intestinal mucosa and reducing the levels of TNFα and LPS.