MLCK在重症急性胰腺炎大鼠胰腺的表达及作用

Expression of MLCK in severe acute pancreatitis in rats

目的:探讨肌球蛋白轻链激酶(myosin light chain kinase,MLCK)在重症急性胰腺炎(severe acute pancreatitis,SAP)大鼠胰腺组织的表达和作用.方法:56只♂SD大鼠,随机分为对照组(C组)和实验组(S组).以4%牛磺胆酸钠胰胆管逆行注射建立SAP大鼠模型,于造模后6、12、24、48 h分批解剖大鼠.动态测定各时点血清淀粉酶(amylase,AMY)水平;光镜下观察胰腺大体及组织学表现;电镜下观察胰腺组织超微结构及紧密连接(tight junction,TJ);免疫组织化学法测定胰腺组织MLCK定位和表达;ELISA法测定血清肿瘤坏死因子-α(tumornecrosis factorα,TNF-α)含量.结果:与对照组相比,S组AMY浓度显著升高(P<0.05);S组胰腺病理学评分显著升高(P<0.05);S组胰腺超微结构破坏明显;T J显著增宽;S组胰腺MLCK阳性表达于胞浆内,平均光密度显著升高(P<0.05);S组血清TNF-α浓度显著升高(P<0.05);胰腺MLCK平均光密度与病理评分、血清TNF-α的Pearson相关分析分别为:r1=0.804,r2=0.796,均P<0.05.结论:SAP大鼠胰腺组织MLCK蛋白、血清TNF-α表达上调,可能通过其调节细胞紧密连接完整性,其可能与疾病严重程度相关,参与急性胰腺炎发病机制.

AIM： To investigate the expression of myosin light chain kinase （MLCK） in pancreatic tissue of severe acute pancreatitis （SAP） rats. METHODS： Fifty-six male SD rats were randomly and equally assigned into a normal control group （C） and a SAP group （S）. SAP was reproduced in rats of group S by retrograde injection of 4% sodium taurocholate into the biliopancreatic duct, while group C underwent a sham operation. The rats were killed at 6, 12, 24 and 48 h after SAP induction. Serum amylase （AMY） was measured dynamically. The gross and pathological changes in the pancreas were observed under a light mi- croscope. The ultrastructure and tight junction （TJ） changes in the pancreas were observed withan electron microscope. The localization and expression of MLCK in pancreatic tissue were in- vestigated by immunohistochemical method. The concentration of serum tumor necrosis factor （TNF-α） was determined by ELISA. RESULTS： Compared to group C, the AMY concentration and pancreatic pathology score were significantly higher （P 〈 0.05）; pancreatic ultrastructure damage was more obvious and TJ widened significantly; MLCK was positively ex- pressed in the cytoplasm of cells in the pancreas, and the mean density was elevated more signifi- cantly （P 〈 0.05）; and serum TNF-（~α concentra- tion significantly increased in group S （P 〈 0.05）. The mean density of MLCK in the pancreas was positively correlated with pathological score and serum TNF-α concentration （r = 0.804, 0.796, P 〈 0.05 for both）.CONCLUSION：Up-regulated expression ofMLCK protein in the pancreas and elevated se-rum TNF-α concentration may regulate the in-tegrity of intercellular tight junctions, which maybe associated with the severity of SAP and play arole in the pathogenesis of acute pancreatitis.