Published online Sep 14, 2019. doi: 10.3748/wjg.v25.i34.5105
Peer-review started: April 12, 2019
First decision: May 24, 2019
Revised: June 14, 2019
Accepted: July 19, 2019
Article in press: July 19, 2019
Published online: September 14, 2019
Non-alcoholic fatty liver disease (NAFLD) has become one of the most major causes of chronic liver disease and affects both adults and children. There are currently no effective treatment options for NAFLD, with the exemption of lifestyle changes. The Chinese herbal medicine (CHM) Dachaihu decoction (DCHD) has been proved to treat NAFLD with good efficacy in previous studies.
Based on the TCM principle of formula formation and good efficacy of CHM, we divided DCHD into soothing liver part, invigorating spleen part, and dredging intestine part. Marshall officially proposed the concept of “intestinal-hepatic axis”, which systematically explains the interactions between intestine and liver. We hypothesized that the effect of CHM on NAFLD is achieved by regulating the liver and intestine.
We aimed to investigate the possible effect of a CHM formula on NAFLD in a rat model, which will provide more evidence for the therapeutic effect of CHM on NAFLD in the future.
Sixty rats were randomly divided into four groups: Control, model, PH, and CHM (Chinese thorowax root, scutellaria root, and white peony root) groups. An NAFLD rat model was established using a high-fat high-fructose diet for 16 wk. From the 13th week, rats in PH group and CHM group were administered with PH solution and a decoction of Chinese thorowax, scutellaria, and white peony root, respectively. Rats in the control group and model group were administered with an equal volume of distilled water. At the end of the study, blood was collected via the abdominal aorta. Liver tissues were harvested and any morphological changes were observed by hematoxylin-eosin (HE) staining, Oil red O staining, and Masson staining. In addition, blood lipids, liver function markers, and TG in liver tissues were analyzed. The levels of transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), Toll-like receptor-4 (TLR4), and nuclear factor-kappa B (NF-кB) in liver tissues and sIgA in intestinal tissues were analyzed by ELISA, and protein and mRNA expression of occludin and ZO-1 in the intestine were measured using Western blot and reverse transcription-quantitative polymerase chain reaction, respectively. The endotoxin level in plasma was detected by endpoint chromogenic assay. SPSS17.0 software package (IBM, Armonk, NY, United States) was used for statistical analysis.
Compared to the normal control group, the liver coefficient, serum TG, TC, LDL, AST, and ALT, blood glucose, the levels of TG, TNF-α, TGF-β, NF-kB, and TLR4 in liver tissues, and plasma endotoxin increased significantly in the model group, while serum HDL, intestinal sIgA, and protein and mRNA expression of occludin and ZO-1 decreased significantly in the model group (P < 0.01). PH and CHM attenuated the elevated liver coefficient, serum TG, TC, LDL, AST, and ALT, blood glucose, the levels of TG, TNF-α, TGF-β, NF-kB, and TLR4 in liver tissues, and plasma endotoxin, and increased serum HDL levels compared to the model group (P < 0.01). Intestinal sIgA and the protein and mRNA expression of intestinal occludin and ZO-1 were significantly increased in the PH group compared to the model and CHM groups (P < 0.01).
In this study, the CHM decoction (Chinese thorowax root, scutellaria root, and white peony root) is beneficial in regulating lipid metabolism and liver function, which indicates that they have a good effect on the liver. To a certain extent, the CHM decoction can affect both the liver and intestine, while the effect of the CHM decoction on the liver is superior to that on the intestine.
This study demonstrated that the mechanism of the soothing liver part of DCHD for the treatment of NAFLD was mainly via the regulation of the liver. The Chinese formula does have its special formation principle. Different CHMs in the same formula are effective on different syndromes. This study proposed formula division and tried to find the relationship between Chinses herbs and internal organs (liver and intestine), which will provide more experimental evidence for the therapeutic effect of CHM on NAFLD in the future. This study preliminary applied the liver-intestine axis to explain the relationship between Chinese formula and NAFLD.