The Role Of P38MAPK-Phsp27 In Vascular Hyporeactivity In Rats With Obstructive Jaundice

?Objective?The definition of hyporesponsiveness of obstructive jaundice is the fluctuation of blood pressure,and bluntness of blood vessels to endogenous and exogenous substances in patients with obstructive jaundice,which could cause hemodynamic instability,seriously affect the treatment and prognosis,and significantly increase perioperative complications and mortality.So far,however,the research of vascular hyporesponsiveness has mainly focused on cardiac function and its integrity,the study of blood vessel itself has been less.This study intends to discuss the role of P38MAPK-Phsp27 in the hyporesponsiveness of obstructive jaundice by animal experiments and cell experiments.?Methods?1 ? Sprague-Dawley(SD)rats were subjected to bile duct ligation surgery,establishing the model of obstructive jaundice rats(bile duct ligation,BDL).Rats were administered with P38 MAPK inhibitor SB203580 by intraperitoneal injection,continuously for seven days after surgery.All rats were separated into four groups according to whether receiving SB203580 or not: Sham group,BDL group,Sham+SB203580 group and BDL+SB203580 group.Serum was reserved for detecting liver function.2?Contractile responses of rats' thoracic aortic rings to different concentrations of noradrenaline(NA)and relaxation response to acetylcholine(Ach)were determined by in vitro experiment of vascular tone.3?The expression of P-Hsp27,F-actin,HSP27,P38 MAPK,and ?-SMA were detected by Westernblot and immunohistochemistry in four groups of rat thoracic aorta.4?The expression of P-Hsp27,F-actin,HSP27,P38 MAPK,and ?-SMA were detected by Westernblot and immunofluorescence in rat thoracic aorta smooth muscle cells with treatment of different concentration gradient of bilirubin and SB203580,cell proliferation was tested by CCK8 assay.?Results?1?Compared with Sham+SB203580 group and Sham group,serum total bilirubin(TB),glutamic acid transaminase(ALT),aspartate aminotransferase(AST)levels were significantly increased in BDL group and BDL+SB203580 group.And compared between BDL group and BDL + SB203580 group,TB,AST and ALT h ad no obvious difference also between Sham group and Sham+SB203580 group.2?Rat vascular tone test results showed that compared with Sham group,contraction and relaxation response of isolated thoracic aorta to NA and Ach were reduced in BDL group.Compared with BDL group,contraction and relaxation response were increased in BDL+SB203580 group.And in Sham+SB203580 group contraction and relaxation responses were not significantly changed compared with Sham group.3?Westernblot and immunohistochemical results showed that in BDL group the expression of P-Hsp27 and F-Actin were significantly higher than that of BDL+SB203580 group,Sham group and Sham+SB203580 group,but no statistically significant difference between the letter three groups;the expression of Hsp27 in the four groups had no statistically significant difference;in BDL group the expression of ?-SMA was lower than BDL+SB203580 group,Sham group and Sham+SB203580 group;the expression of P38 MAPK was low in BDL+SB203580 group and Sham+SB203580 group.4?CCK8 assay showed that with the increase of bilirubin concentration gradient,cell proliferation was gradually reduced,cell proliferation was significantly increased in the concentration of 100,200,400umol/L bilirubin group cultured with SB203580.there were significant differences in cell proliferation.Westernblot and immunofluorescence results showed that increasing of bilirubin concentration gradient,the expression of P-Hsp27 and F-actin were increased gradually,but they were decreased after cultured with SB203580;the expression of Hsp27 was almost constant in different bilirubin concentration gradient and treatment of SB203580;the expression of P38 MAPK was all decreased cultured with SB203580.The results of this research show that inhibited the phosphorylation of Hsp27 through the P38 MAPK pathway can improve vascular contraction and relaxation reaction of obstructive jaundice rats,also can reduce the expression of P-Hsp27 and F-Actin and increase ?-SMA expression,indicating the number of vascular smooth muscle cells is decreased with obstructive jaundice rats.Cultured with different bilirubin concentration gradient in rat vascular smooth muscle cells,the expression of P-Hsp27 and F-actin are significantly increased,indicating the actin cytoskeleton polymerization id remodeled.Cultured with SB203580 in cells,the phosphorylation of Hsp27 is inhibited and the expression of F-actin is decreased,indicating the actin cytoskeleton remodeling has been reversed.In conclusion,this study demonstrated that inhibition of Hsp27 phosphorylation could improve vascular contraction and relaxation reaction of obstructive jaundice rats,related to vascular smooth muscle cell actin cytoskeleton remodeling probably.