Effects Of Ursolic Acid On Hepatic Fibrosis And Expression Of TGFβ1 In Rats

Background: Hepatic fibrosis occurs in the course of wound healing in response to chronic liver injury, which is characterized by the excess deposition of extracellular matrix components. This response represents the final common pathway for many chronic liver diseases. Some studies showed that hepatic fibrosis can be reversed. But there is no effective medicine of anti-hepatic fibrosis in clinic. It is found Chinese herbal medicine had satisfactory therapeutic effect of anti-hepatic fibrosis. According to our pre-project works and the advancements in domestic and abroad, we used different concentrations ursolic acid to treat hepatic fibrosis rats to explore therapeutical effects and mechanisms of ursolic acid anti-hepatic fibrosis.Objective: To obsere the effect of ursolic acid on hepatic fibrosis in rats and explore the possible mechanisms of ursolic acid anti-hepatic fibrosis. Materials and Methods: Hepatic fibrosis rats model was set up by intraperitoneal injection of DMN (ip, 10 mg/mL per kg) for 3 consecutive days per week for 4 weeks. The nomal control group was treated with the volume of saline equivalent to those of other groups. Hepatic fibrosis rats were randomly divided into 5 groups: medel group was treated with the volume of saline equivalent to those of the UA groups per day; colchine group was treated with intraperitoneal injections of colchine at a dose of 0.1mg/kg per day; UA groups were treated with intraperitoneal injections of ursolic acid at doses of 10mg/kg(UA-1), 20mg/kg(UA-2), 40mg/kg(UA-3) per day. Serum ALT,AST,TP,ALB,A/G were detected by entire automatic biochemistry meter after drug treatment for 2 and 4 weeks. After drug treatment for 4 weeks, serum SOD,MDA were detected by TBA method; the ecxpression ofα-SMA protein was detected by Westernblot; the ecxpression of TGFβ1mRNA was detected by RT-PCR, the ecxpression of TGFβ1 protein was detected by immunohistochemistry.Results: 1. In model control group, serum ALT,AST increased, serum ALB,A/G decreased(P<0.01)compared with normal group(P>0.05). After treatment with colchine and ursolic acid for 2 and 4 weeks, ALT,AST decreased and ALB,A/G increased(P<0.05,P<0.01)compared with model control group(P>0.05). Curative effect of ursolic acid at doses of 20mg/kg/d,40mg/kg/d were better than that of colchin(eP<0.05,P<0.01). Curative effect of ursolic acid at doses of 40mg/kg/d were better than that of 20mg/kg/d(P<0.05).2. In model control group, the macroscopic observation of liver showed that the cubic capacity increased, color becomed shallow, borderline becomed blunt, surface had coarse grains and adhered with surrounding organs; treatment with colchine and ursolic acid for 4 weeks, the macroscopic observation showed liver appearances improved. In model control group, HE stain showed that hepatic lobules architectonic confused, hepatic cell necrosis, the cell of Leydig widespread and increased, collagen fibers were distinctly deposited; VG stain showed that fibrous septum formed, the collagen deposited in sinus hepaticus consecutively or disconsecutively, and the collagen deposition increased compared with nomal control group(P<0.01). In UA-2,UA-3 groups, HE and VG stain showed that hepatic lobules architectonic confuse improved and hepatic cell death relieved, collagen deposition reduced significantly compared with model control group(P<0.05,P<0.01). Ursolic acid on hepatic fibrosis was more effective than colchine(P<0.05,P<0.01). There were no significant differences between colchine group and model control group(P>0.05).3. In model control group, serum SOD reduced significantly (P<0.01) and serum MDA increased significantly compared with nomal control group(P<0.01). In UA groups, serum SOD increased significantly compared with model control group (P<0.01), but colchine group had no change compared with model control group(P>0.05); serum MDA reduced significantly in treatment with ursolic acid and colchine groups(P<0.01). There were obvious differences between ursolic acid groups and colchine group(P<0.01).4. In model control group, the expression ofα-SMA protein increased significantly compared with nomal control group(P<0.01). In UA groups, the expression ofα-SMA protein reduced significantly(P<0.01) compared with model control group; but there are no differences between model control groups and colchine group(P>0.05). In UA-2 and UA-3 groups, the expression ofα-SMA protein reduced significantly compared with colchine group(P<0.01).5. In model control group, the expression of TGFβ1mRNA increased significantly compared with nomal control group(P<0.01). In UA groups, the expression of TGFβ1mRNA reduced significantly(P<0.05, P<0.01) compared with model control group. In colchine group, the expression of TGFβ1mRNA reduced significantly compared with model control group(P<0.05). In UA-2 and UA-3 groups, the expression of TGFβ1mRNA protein reduced significantly compared with colchine group(P<0.05, P<0.01).6. In nomal control group, the expression of TGFβ1 protein were extremely low. In model control group, the expression of TGFβ1 protein increased significantly compared with nomal control group(P<0.01). In UA groups, the expression of TGFβ1 protein reduced significantly (P<0.01) compared with model control group. In colchine group, the expression of TGFβ1 protein reduced significantly compared with model control group(P<0.05). In UA-2 andUA-3 groups, the expression of TGFβ1 protein reduced significantly compared with colchine group(P<0.01).Conclusions:①Ursolic acid could significantly improve hepatic function. It is of hepatic fibrosis rats showed that the contents of ALT,AST increased, the contents of ALB,A/G reduced after treatment with different concentrations ursolic acid. Curative effect of ursolic acid at doses of 20mg/kg/d,40mg/kg/d were better than that of colchine(P<0.05,P<0.01). The histopathology showed that hepatic lobules architectonic confuse improved, hepatic cell death reduced, the collagen deposition relieved significantly in a dose-dependent manner. Ursolic acid on hepatic fibrosis was more effective than colchine. Treatment with 40mg/kg/d group was more effective than 20mg/kg/d group.②The mechanism of ursolic acid anti-hepatic fibrosis possibly associated with: 1) intercepted oxidative stress and lipid peroxidation by increasing serum SOD and reducing serum MDA; 2)through down-regulating the expression ofα-SMA protein, active HSC in hepatic tissue decresased, and the secretion of collagenⅠ,Ⅲreduced accordingly; 3) through down-regulating expression of TGFβ1mRNA and TGFβ1 protein, reduced the secretion of collagen and increased the degradation, thereby the deposition of ECM reduced.