The underlying mechanism of autophagy regulating liver injury with obstructive jaundice in Sprague-Dawley rats / 中华肝胆外科杂志

ABSTRACT

Objective:To investigate the effect of autophagy on liver injury with obstructive jaundice in Sprague-Dawley (SD) rats and its underlying mechanism.Methods:Thirty-five healthy male SD rats, SPF grade, aged 6-8 weeks, weighting 200-300 g, were divided into 5 groups with 7 rats in each group, including sham group (simple free common bile duct, without ligation, intraperitoneal injection of normal saline), obstructive jaundice (OJ) group (established by common bile duct ligation, intraperitoneal injection of normal saline), OJ group with 3-MA, OJ group with Rapamycin, and OJ group with 3-MA and VX-765. Morphological changes in liver tissues were analyzed with HE staining. Expression of autophagy-related protein Atg5 was detected by immunohistochemistry staining. Liver function was analyzed by automatic biochemical instrument and the level of serum interleukin (IL)-18 was detected using ELISA assay. Protein levels of autophagy related-proteins and endoplasmic reticulum stressed (ERs)-related apoptosis proteins were detected by Western Blot.Results:The relative expression of autophagy related protein Atg5 in OJ group was significantly higher than that in sham group [(5.0±1.0) vs. (2.8±1.3), t=-3.00, P<0.05]. Compared with sham group, the activity of autophagy was enhanced and the protein levels of Caspase-1/p-65 and IL-18 were significantly increased in OJ group. At the same time, apoptosis was induced by activating ERs. In OJ group, the autophagy inducer 3-MA improved the expression levels of Caspase-1/p-65 and IL-18, and aggravate liver injury. While after applying the autophagy agonist Rapamycin in OJ rat models, the expression of Caspase-1/p-65 and IL-18 was repressed and liver damage was also reduced. In addition, in rat OJ groups with 3-MA, inhibition of Caspase-1 by VX-765 could down regulate the expression of Caspase-1/p-65 and IL-18, and protect against liver injury. Conclusions:Both ERs related apoptosis and autophagy were activated after ligation of common bile duct. Besides, activation of autophagy could reduce OJ-induced liver injury in SD rats by inhibiting the Caspase-1/p-65 inflammatory pathway.