摘要
To study the molecular mechanisms involved in the hepatoprotective effects of naringenin (NAR) on carbon tetrachloride (CCl<sub>4</sub>)-induced liver fibrosis. METHODSThirty-two male Wistar rats (120-150 g) were randomly divided into four groups: (1) a control group (n = 8) that received 0.7% carboxy methyl-cellulose (NAR vehicle) 1 mL/daily p.o.; (2) a CCl<sub>4</sub> group (n = 8) that received 400 mg of CCl<sub>4</sub>/kg body weight i.p. 3 times a week for 8 wk; (3) a CCl<sub>4</sub> + NAR (n = 8) group that received 400 mg of CCl<sub>4</sub>/kg body weight i.p. 3 times a week for 8 wk and 100 mg of NAR/kg body weight daily for 8 wk p.o.; and (4) an NAR group (n = 8) that received 100 mg of NAR/kg body weight daily for 8 wk p.o. After the experimental period, animals were sacrificed under ketamine and xylazine anesthesia. Liver damage markers such as alanine aminotransferase (ALT), alkaline phosphatase (AP), γ-glutamyl transpeptidase (γ-GTP), reduced glutathione (GSH), glycogen content, lipid peroxidation (LPO) and collagen content were measured. The enzymatic activity of glutathione peroxidase (GPx) was assessed. Liver histopathology was performed utilizing Masson’s trichrome and hematoxylin-eosin stains. Zymography assays for MMP-9 and MMP-2 were carried out. Hepatic TGF-β, α-SMA, CTGF, Col-I, MMP-13, NF-κB, IL-1, IL-10, Smad7, Smad3, pSmad3 and pJNK proteins were detected via western blot. RESULTSNAR administration prevented increases in ALT, AP, γ-GTP, and GPx enzymatic activity; depletion of GSH and glycogen; and increases in LPO and collagen produced by chronic CCl<sub>4</sub> intoxication (P < 0.05). Liver histopathology showed a decrease in collagen deposition when rats received NAR in addition to CCl<sub>4</sub>. Although zymography assays showed that CCl<sub>4</sub> produced an increase in MMP-9 and MMP-2 gelatinase activity; interestingly, NAR administration was associated with normal MMP-9 and MMP-2 activity (P < 0.05). The anti-inflammatory, antinecrotic and antifibrotic effects of NAR may be attributed to its ability to prevent NF-κB activation and the subsequent production of IL-1 and IL-10 (P < 0.05). NAR completely prevented the increase in TGF-β, α-SMA, CTGF, Col-1, and MMP-13 proteins compared with the CCl<sub>4</sub>-treated group (P < 0.05). NAR prevented Smad3 phosphorylation in the linker region by JNK since this flavonoid blocked this kinase (P < 0.05). CONCLUSIONNAR prevents CCl<sub>4</sub> induced liver inflammation, necrosis and fibrosis, due to its antioxidant capacity as a free radical inhibitor and by inhibiting the NF-κB, TGF-β-Smad3 and JNK-Smad3 pathways.
AIM To study the molecular mechanisms involved in the hepatoprotective effects of naringenin(NAR)on carbon tetrachloride(CCl4)-induced liver fibrosis.METHODS Thirty-two male Wistar rats(120-150 g)were randomly divided into four groups:(1)a control group(n=8)that received 0.7%carboxy methyl-cellulose(NAR vehicle)1 m L/daily p.o.;(2)a CCl4 group(n=8)that received 400 mg of CCl4/kg body weight i.p.3 times a week for 8 wk;(3)a CCl4+NAR(n=8)group that received 400 mg of CCl4/kg body weight i.p.3times a week for 8 wk and 100 mg of NAR/kg body weight daily for 8 wk p.o.;and(4)an NAR group(n=8)that received 100 mg of NAR/kg body weight daily for 8 wk p.o.After the experimental period,animals were sacrificed under ketamine and xylazine anesthesia.Liver damage markers such as alanine aminotransferase(ALT),alkaline phosphatase(AP),γ-glutamyl transpeptidase(γ-GTP),reduced glutathione(GSH),glycogen content,lipid peroxidation(LPO)and collagen content were measured.The enzymatic activity of glutathione peroxidase(GPx)was assessed.Liver histopathology was performed utilizing Masson’s trichrome and hematoxylin-eosin stains.Zymography assays for MMP-9 and MMP-2 were carried out.Hepatic TGF-β,α-SMA,CTGF,Col-I,MMP-13,NF-κB,IL-1,IL-10,Smad7,Smad3,p Smad3 and p JNK proteins were detected via western blot.RESULTS NAR administration prevented increases in ALT,AP,γ-GTP,and GPx enzymatic activity;depletion of GSH and glycogen;and increases in LPO and collagen produced by chronic CCl4 intoxication(P<0.05).Liver histopathology showed a decrease in collagen deposition when rats received NAR in addition to CCl4.Although zymography assays showed that CCl4 produced an increase in MMP-9 and MMP-2gelatinase activity;interestingly,NAR administration was associated with normal MMP-9 and MMP-2 activity(P<0.05).The anti-inflammatory,antinecrotic and antifibrotic effects of NAR may be attributed to its ability to prevent NF-κB activation and the subsequent production of IL-1 and IL-10(P<0.05).NAR completely prevented the increase in TGF-β,α-SMA,CTGF,Col-1,and MMP-13 proteins compared with the CCl4-treated group(P<0.05).NAR prevented Smad3phosphorylation in the linker region by JNK since this flavonoid blocked this kinase(P<0.05).CONCLUSION NAR prevents CCl4 induced liver inflammation,necrosis and fibrosis,due to its antioxidant capacity as a free radical inhibitor and by inhibiting the NF-κB,TGF-β-Smad3 and JNK-Smad3 pathways.
基金
Supported by National Council of Science and Technology(Conacyt)of Mexico,No.253037 to Muriel P,and No.239516 to Segovia J
Fellowship No.358378 Hernández-Aquino E to from Conacyt
supported by a grant of PRODEP(UABC-PTC-464)Mexico
