| Background and objective:Hepatic fibrosis (HF) represents a wound-healing process in response to a variety of chronic live injury, characterized by activation of hepatic stellate cell (HSC) and accumulation of extracellular matrix proteins (ECM). The excess deposition of ECM disrupts the normal architecture of the liver leading to the organ failure. If we can stop the fibrosis of the liver, the cirrhosis and liver cancer will be avoided. In the pathogenic course, oxidative stress (OS) was involved in a different degree which would lead to accumulate a lot of reactive oxygen species (ROS). ROS plays an important role in the activation, proliferation and reorganization of HSC and collagen synthesis. Several recent studies have demonstrated that the rennin-angiotensin system (RAS) is closely related to hepatic fibrosis. The role of the classical axis ACE-AngⅡ-AT1R is considered to play a catalytic role in the process of HF, ACE2-Ang(1-7)-Mas axis appears to exert a counter-regulation role in liver tissue with axis ACE-Ang Ⅱ-AT1R and play a protective role in the process of HF. But it is unclear that the mechanism of HF induced by RAS. It may bring a new way for the therapy to explore the effect of the two axis on HF. PPAR-y, NF-κB and Nrf2pathway are closely correlated with inflammation, apoptosis of hepatocyte, activation and proliferation of HSC and the balance between oxidative system and anti-oxidative system. They also interact with each other. Therefore, it is speculated that the signal transduction mechanism of ROS-RAAS may related with PPAR-y, NF-κB and Nrf2pathway. In this thesis, we used Electron spin resonance (ESR) to measure free radicals from the process of HF and explored the effect of HF induced by porcine serum in rats on the pathway of ROS-RAAS and intervention effect of Biejiajian oral liquid (BOL). All of those would provide a new mentality for liver fibrosis early clinical intervention. Methods:Hepatic fibrosis is induced by porcine serum in rats. In addition, ESR was used to capture the free radicals in rat liver homogenate. Rats were randomly assigned to treatment group and prevention group. Each group is divided into six groups:normal group, model group, VE group, Ena group, BOL high and low does groups. The pathological changes were evaluated by hematoxylin-eosin (HE) staining. The levels of AngⅡ and Ang(1-7) in different times were measured by Elisa GEN, AGT, ACE, AT1R and CYPllb2mRNA expression were determined by RT-PCR ACE, ACE2, ATiR, Mas immunoreactivities were assessed by immunohistochemical technology, the expressions of five proteins in PPAR-γ, NF-κB, Nrf2signal pathway were detected by Western blot. Results:(1) After being injected of porcine serum, Lobules of liver in the rats of model group was disorder with a pile of deposition of fibrous tissue and inflammatory cell infiltration. BOL can protect hepatic cell, inhibit collagen synthesis and enhance collagen degradation.(2) Alkane radicals were detected in porcine serum induced fibrotic rat liver, and BOL could eliminate free radicals. BOL can protect hepatic cell, inhibit collagen synthesis and enhance collagen degradation.(3) RAAS in fibrotic rat was activated. The levels of AngⅡ and Ang(1-7) and the expressions of ACE、ACE2、AT1R and Mas were increased in porcine serum induced fibrotic rat liver. After being treated with BOL, the level of Ang Ⅱ and the expressions of ACE and AT1R were decreased, to the opposite, that of Ang(1-7), ACE2and Mas constantly increasing.(4) The mRNAs expressions of all the components in RAAS:RT-PCR shows that mRNAs of all the components in RAAS could be expressed in normal group. GEN, AGT, ACE, ATiR and CYPllb2expressions increased in liver fibrosis. BOL suppressed the expressions of all the components significantly.(5) The effect of BOL on the signaling pathways of PPAR-y, NF-κB, Nrf2in porcine serum intoxicated rat liver:BOL inhibited hepatic fibrosis by increasing the expressions of PPAR-γ, IκBα, Nrf2while decreasing the expressions of NF-κB and Keap1. Conclusion:(1) Alkane radicals were detected in porcine serum induced fibrotic rat liver. BOL can scavenge free radicals.(2) In the process of HF, the activity of hepatic RAAS increased, ACE-Ang Ⅱ-AT1R axis may play a catalytic role in the process of HF, while ACE2-Ang-(1-7)-Mas axis may play a protective role in it. Besides, BOL inhibited hepatic fibrosis by influencing RAAS.(3) Influencing the signaling pathways of PPAR-y, NF-κB and Nrf2may be one mechanism of anti-liver fibrosis effect of BOL in porcine serum induced fibrotic rats. |
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