# Huanggan decoction ameliorates cholestatic hepatic fibrosis in rats via TGF-β1/Smad3 signaling pathway

## TL;DR

Huanggan Decoction helps reduce liver fibrosis in rats by affecting the TGF-β1/Smad3 pathway and reducing inflammation.

## Contribution

The study reveals the mechanism by which Huanggan Decoction ameliorates cholestatic liver fibrosis through the TGF-β1/Smad3 signaling pathway.

## Key findings

- HGD reduced serum liver fibrosis biomarkers and inflammatory cytokines in rats.
- HGD decreased collagen deposition and improved liver pathology in cholestatic liver fibrosis.
- HGD modulated the TGF-β1/Smad3 pathway by altering MMP1, TIMP1, and p-Smad3 levels.

## Abstract

Huanggan Decoction (HGD), as a special Chinese medicine preparation, has good effects in clearing heat, removing dampness, eliminating jaundice. HGD has been used in medical institutions for more than 40 years, and shows an outstanding curative effect in jaundice and cholestatic liver diseases (CLD), makes up for the deficiency of the treatment of CLD. However, the underlying mechanisms of HGD for its therapeutic effects are still not well understood.

The hepatoprotective properties of HGD were assessed using a cholestatic liver fibrosis (CLF) rat model induced by ANIT. Serum liver function index was analyzed by automatic chemical analyzer. Serum biomarkers of liver fibrosis and inflammatory factors were detected by ELISA kits. Liver pathology and collagen fiber extent were assessed using HE and Masson’s stains. Expressions of pro-fibrotic cytokine TGF-β1 and the indicator of HSC activation α-SMA in liver were assayed by immunohistochemistry. The levels of Smad3, phosphorylated Smad3, MMP1 and TIMP1 were assayed by western blotting.

HGD dramatically decreased the serum biochemical indexes, down-regulated the serum biomarkers of liver fibrosis and inflammatory cytokines, reduced the collagen deposition, ameliorated pathological damage. At the same time, HGD notably reduced the level of α-SMA. Additionally, HGD increased MMP1 protein level while decreasing TIMP1 protein level and the p-Smad3 to Smad3 ratio.

Findings suggest that HGD demonstrated a remarkable liver-protective effect, potentially linked to halting liver fibrosis progression by maintaining the equilibrium between MMP1 and TIMP1, modulating TGF-β1/Smad signal pathway, suppressing HSC activation, and exhibiting anti-inflammatory characteristics.