Effects Of Paeoniflorin On IL-13/STAT6 Signalling In Hepatic Fibrosis Of Schistosomiasis Japonicum

Schistosomiasis is one of the major diseases in the developing country. The primary reason of death in schistosomiasis is the formation of liver egg granulomas and secondary hepatic fibrosis. Studies have showed that granuloma inflammatory reaction and fibrosis in liver tissue would continue to be aggravated, even though schistosomicides were given.If fibrosis has reached a centain degree,then it will countinue to aggravate,eventhough the previous causative agents are eradiated.So the intervention and control of such aggravation during or before the formation of granuloma or at the early stage of fibrosis become another key therapeutic strategy after. However, so far no anti-fibrosis drug with low toxicity and high efficiency has been applied to prevent or reverse the hepatic fibrosis in schistosomiasis.AIM To investigate the effects of PAE on IL-13/STAT6 signalling in hepatic fibrosis of schistosomiasis japonica in mouseMETHODS The mice were infected with S. japonicum cercariae.On 12 days pastinfaction,the mice of drug group were orally given PAE 0.2 ml, 60mg/ (kg·d)×30 d, the control and model groups were given 0.5% sodium carboxymethycellulose×30 d,each of groups was rally given praziquantel 0.2 ml,500 mg/ (kg·d)×2 d,on 42 day pastinfection. Mice were sacrificed by cervical dislocation on 8 weeks and 12 weeks after infection. Serum hyaluronic acid (HA) was detected by radioimmunoassay; hepatic Hydroxyproline (HYP) was detected by alkaline lysis; the area of egg granuloma and degree of hepatic fibrosis were observed via HE and Masson stainings;the expression ofα-SMA, IL-13, STAT6 and IL-13Rα1 protein were measured by immnohistochemical method; the expression of ColⅠand ColⅢRNA were measured by RT-PCR.The effects of rIL-13 and PAE on proliferation of 3T3 cells were measured by CCk-8 in vitro and Hydroxyproline content in cell supernatant was determined by alkaline lysis method. IL-13Rα1,α-SMA and STAT6 protein expression in 3T3 cells were detected by Western Blotting. Col-Ⅰ, Col-Ⅲ, IL-13Rα1 and STAT6 RNA expression in 3T3 cells were analyzed by RT-PCR.RESULTS On 8 weeks and 12weeks postinfection, the level of HA and HYP in model group were higher (P <0.01) than other groups; the area of granuloma and the degree of hepatic fibrosis in model group were significantly increased (P<0.01);the expression ofα-SMA in model group was more obvious (P<0.01) than other groups; the expression of IL-13 in model group were higher (P<0.01) than drug group;the expression of STAT6,IL-13Rα1 in model group were higher (P<0.01) than drug group on 8 weeks and no observated on 12 weeks;the level of ColⅠand ColⅢRNA in model group were higher (P<0.01)than other groups.In vitro paeoniflorin could inhibit 3T3 cells proliferation in a concentration-dependent manner (P<0.01), and there was a statistically significant difference among all groups (P<0.01). rIL-13 caused a remarkably concentration-dependent increase in proliferation of 3T3 cells (P<0.05). Paeoniflorin (200, 400, 600, 800, and 1 000 mg/L) could inhibit proliferation of 3T3 cell stimulated by rIL-13 in a concentration-dependent manner (P<0.01), and among all groups there existed a significant difference (P<0.01). Moreover, paeoniflorin also could suppress secretion of hydroxyproline from 3T3 cell stimulated by rIL-13 in a concentration-dependent manner (P<0.01) with a statistical significance among all groups (P < 0.01). Further investigations showed that paeoniflorin could decrease both protein expression ofα-SMA, IL-13Rα1,STAT6, and RNA expression of Col-Ⅰ, Col-Ⅲ, IL-13Rα1, STAT6 in 3T3 cell stimulated by rIL-13. CONCLUSIONS1. PAE could inhibit formation of hepatic granuloma and fibrosis and reduce expression of related proteins in IL-13/STAT6 signal pathway in liver tissue of mouse with schistosomiasis;2. The anti-fibrotic role of PAE in schistosomiasis might be associated with it's inhibitory effect on HSC activation,proliferation and meanwhile on IL-13/STAT6 signalling.