Curcumin Promotes Apoptosis of Activated Hepatic Stellate Cells by Inhibiting Protein Expression of the MyD88 Pathway.

Activation and proliferation of hepatic stellate cells (HSC) play an important role in the progress of liver fibrosis. HSC activation occurs in response to inflammatory cytokines, cellular interactions with immune cells, and morphogenetic signals. The literature hints to a role of the adaptor protein MyD88 in fibrosis. Although curcumin has been shown to exert inhibitory effects on the proliferation of HSC in vitro, its influence on the MyD88 pathway in HSC has remained unclear. Here, we investigated whether curcumin accelerates apoptosis of HSC through the MyD88 pathway. HSC (rat HSC T6) were divided into a control group, MyD88 small interfering RNA (siRNA) group, curcumin group, and curcumin + MyD88 siRNA group. The MyD88 siRNA groups were exposed to siRNA for 48 h. The curcumin groups were cultured in the presence of curcumin for 24 h. Apoptosis was detected by flow cytometry. For Toll-like receptor (TLR) 2 and 4 as well as MyD88 and the dependent factors NF-κB, TNF-α, and IL-1ß, mRNA expression was detected by reverse transcription polymerase chain reaction (RT-PCR). For MyD88, protein expression was further observed by Western Blot. Both curcumin and MyD88 siRNA inhibited the mRNA expression of MyD88 pathway-related effectors (TLR2, TLR4, NF-κB, TNF-α, IL-1ß) in HSC. Furthermore, both treatments reduced the expression of MyD88 protein in HSC and promoted their apoptosis. These effects were more obvious in the curcumin + MyD88 siRNA group. This study demonstrates that curcumin promotes apoptosis of activated HSC by inhibiting the expression of cytokines related to the MyD88 pathway. It elucidates the possible mechanisms of curcumin in inducing apoptosis of HSC through the MyD88 pathway.

[Preliminary study on mechanism of therapeutic effect of Huganjiexian decoction on hepatic fibrosis].

OBJECTIVE: To observe the effects of Huganjiexian decoction on rat hepatic fibrosis and the creation of cytokines. METHODS: Rat hepatic fibrosis was induced by intraperitoneally injection of carbon tetrachloride. At the same time, these rats were treated with different dosages of Huganjiexian decoction. Sho-saiko-to compound treating group and Fufangbiejiarangan Tablets treating group were used as positive controls. After twelve weeks, all rats were executed. Histopathologic changes were observed after H.E and Masson stainings. The expression of collagen type I, collagen type III, TGF-beta 1 and PDGF-BB in liver were detected by immunohistochemical staining. RESULTS: Compared with fibrotic group, hepatic fibrosis in decoction groups was significantly improved. In decoction groups, levels of collagen type I, collagen type III, TGFbeta1 and PDGF-BB were decreased, especially in the low-dose curcumin group. The TGF-beta 1 positive percentage were 7.56%+/-2.18%, 29.25%+/-7.84%, 13.54%+/-4.15%, 21.82%+/-6.64%, 20.06%+/-7.14%, 13.78%+/-4.35%, 12.75%+/-3.98% in liver tissues from normal group, model group, low, middle, high curcumin, Sho-saiko-to compound and Fufangbiejiarangan Tablets treating groups respectively (P less than 0.05); while the PDGF-BB positive percentage were 1.68%+/-0.41%, 11.70%+/-2.28%, 3.65%+/-0.76%, 5.24%+/-1.04%, 6.37%+/-1.12%, 4.16%+/-0.61%, 3.38%+/-0.56% in liver tissues from those groups respectively (P less than 0.05). CONCLUSION: Huganjiexian decoction can improve rat hepatic fibrosis, possibly via inhibiting the expression of collagen type I, collagen type III, TGFbeta1 and PDGF-BB.

Curcumin prevents liver fibrosis by inducing apoptosis and suppressing activation of hepatic stellate cells.

This study was designed to investigate the prophylactic effects and the mechanisms of curcumin on liver fibrosis in rats. Liver fibrosis was induced in 72 Sprague Dawley rats by intraperitoneal injection of carbon tetrachloride. Rats were divided into control, liver fibrosis, high, medium, and low dose curcumin (200, 100, and 50 mg kg(-1), respectively), and colchicine (0.1 mg kg(-1)) groups. After 8 weeks of treatment, histopathological examination was performed on hepatic tissues, and liver fibrosis was graded. Hepatic stellate cells activity was examined by smooth muscle alpha-actin immunohistochemistry staining, and apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling. The liver fibrosis score in the high, medium, and low dose curcumin group (5.79 +/- 1.80, 8.58 +/- 3.34, and 9.58 +/- 3.32, respectively) and the colchicine group (4.91 +/- 1.28) was significantly lower than in the fibrosis group (20.40 +/- 3.38, P < 0.01). The ratio of activated hepatic stellate cells in the three curcumin groups (0.97 +/- 0.69, 2.06 +/- 0.58, and 3.49 +/- 1.03, respectively) and the colchicine group (0.78 +/- 0.31) was significantly lower than in the fibrosis group (6.08 +/- 1.13, P < 0.05). The apoptosis index in the three curcumin groups (0.57 +/- 0.21, 0.37 +/- 0.22, and 0.34 +/- 0.21, respectively) was higher than in the fibrosis (0.09 +/- 0.09, P < 0.05) or the colchicine group (0.16 +/- 0.19, P < 0.05). Curcumin prevents carbon tetrachloride-induced liver fibrosis in rats. The prevention of liver fibrosis may be due to the inhibition of the activation of hepatic stellate cells and induction of their apoptosis.

[Therapeutic effects of curcumin treatment on hepatic fibrosis].

OBJECTIVE: To investigate the therapeutic effects and mechanisms of curcumin treatment on hepatic fibrosis. METHODS: A model of hepatic fibrosis was established using carbon tetrachloride intraperitoneal injections in rats. Curcumin was administered to one group of the model rats (curcumin group) and the other rats were used as controls (control group). Serum levels of ALT, AST, HA, LN, PCIII, and NO were measured, and Hyp, MDA, and SOD in liver tissues were measured. Liver tissue slides were stained with HE and Masson staining to study the pathological changes in the livers. Grades of hepatic fibrosis were evaluated according to a semiquantitative scoring system. RESULTS: In the curcumin group, serum levels of ALT, AST, NO, HA, LN, PCIII, MDA, and Hyp, were (218.50+/-48.89) U/L, (376.60+/-79.13) U/L, (47.96+/-6.53) micromol/L, (289.96+/-60.43) mg/L, (107.35+/-27.24) mg/L, (148.95+/-28.63) microg/L, (236.10+/-30.54) nmol/g, (478.40+/-75.74) microg/g and all were lower than those of the control group (693.75+/-117.57) U/L, (892.50+/-105.69) U/L, (70.95+/-10.23) micromol/L, (468.22+/-93.45) mg/L, (346.44+/-75.08) mg/L, (279.82+/-54.00) microg/L, (402.25+/-39.16) nmol/g, and (752.50+/-77.62) microg/g. The differences were significant. In the curcumin group, the level of SOD (90.39+/-21.23) in the liver tissues was significantly higher than that of the control group (46.52+/-20.01). The hepatic fibrosis scores in the curcumin group were significantly lower than those of the control group. These effects were dose-dependent. CONCLUSIONS: Curcumin reduces rat hepatic fibrosis. Anti-peroxidation and regulation of collagen metabolism in liver tissues may be involved in the therapeutic effectiveness of curcumin on hepatic fibrosis.

[The study of therapeutic effects of curcumin on hepatic fibrosis and variation of correlated cytokine].

OBJECTIVE: To investigate therapeutic effects of curcumin on hepatic fibrosis and the variation of correlated cytokine. METHODS: Rat models of hepatic fibrosis were made by carbon tetrachloride. Curcumin of 10, 20, 40 mg per 100 gram weight of rat were given to these rats of curcumin group respectively from ninth week. Normal, dissolvent, model and Salvia miltiorrhiza groups were made as controls. Serum levels of ALT, AST, HA, LN, PC-III were detected; Serum levels of TGF-beta1 and TNF-alpha were detected by ELISA method; Serum levels of NO were detected by chemical method. HE and Masson staining were conducted in hepatic tissues to observe pathological variations. Grades of hepatic fibrosis were evaluated according to SSS system. Immunohistochemical staining was executed for detecting PDGF-BB in liver, and professional software for image analysis was used. RESULTS: Curcumin could decrease serum levels of ALT, AST, HA, LN, PC-III obviously, P < 0.05, which were increased in fibrotic group. Curcumin could decrease cytokine levels of NO, TGF-beta1, TNF-alpha, P < 0.05. Curcumin could obviously improve liver pathological variations of fibrotic rats. The score of hepatic fibrosis in curcumin group reduced significantly, P < 0.05. Curcumin treatment could reduce the expression of PDGF-BB, P < 0.05. These effects were dose-dependent. CONCLUSION: Curcumin can heal rat hepatic fibrosis. Effects of reducing the expression of correlated cytokines may be mechanisms of therapeutic effects of curcumin on hepatic fibrosis.

[Prophylactic effect of curcumin on hepatic fibrosis and its relationship with activated hepatic stellate cells].

OBJECTIVE: To observe the prophylactic effect of curcumin on hepatic fibrosis and the number, location, apoptosis of activated hepatic stellate cells (HSCs) in the livers and to discuss the relationship between the prophylactic effects and activated HSC. METHODS: A rat model of hepatic fibrosis was established by intraperitoneal injection of carbon tetrachloride. Curcumin doses of 5 mg, 10 mg, 20 mg per 100 gram per 100g of body weight were given to three groups of the model rats. No curcumin was given to one group of the model rats and it served as the control. After eight weeks, all rats were sacrificed and their left liver lobes were examined histopathologically with H.E and Masson stainings. Grades of hepatic fibrosis were evaluated according to the SSS system. Activated HSC was detected by the alpha-SMA immunohistochemistry staining. HSC apoptosis was detected by double-stainings of terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) and desmin immunohistochemistry staining. RESULTS: Degrees (SSS system scores) of hepatic fibrosis in the curcumin groups were all less severe in comparison with those of the control group. Activated HSCs in the livers of the rats of the control group increased significantly compared with that of the treatment groups, and also fewer apoptotic HSCs were detected in the control group. On the contrary, fewer activated HSCs and more apoptotic HSCs were detected in the curcumin groups compared with those of the control group. The degrees of the effects were curcumin dose-dependent. CONCLUSIONS: Curcumin can prevent hepatic fibrosis. It can inhibit activation and proliferation of HSCs and induce HSCs apoptosis, which may be the mechanism(s) contributing to the prophylactic effects of curcumin on hepatic fibrosis.