蛇菰多糖降低实验性肝损伤大鼠肝脏BDNF和TrkB的表达

Balanophora polysaccharide decreases the expression of BDNF and TrkB in liver tissues of rat with experimental liver injury

目的蛇菰多糖(BPS)对D-半乳糖(D-gal)所致实验性肝损伤大鼠的肝功能及肝组织内BDNF、TrkB蛋白和凋亡相关蛋白表达的影响。方法将大鼠随机分为对照组(control),D-gal组(皮下注射D-半乳糖200 mg/kg),BPS低(D-gal+BPS-L)、中(D-gal+BPS-M)、高(D-gal+BPS-H)剂量组,分别每天灌胃50、100和200 mg/kg BPS,共6周。心脏取血检测血清谷丙转氨酶(ALT)和谷草转氨酶(AST)水平;HE染色法观察肝组织形态;免疫组织化学染色检测BDNF和TrkB的定位;Western blot检测BDNF、TrkB、Bcl-2、caspase-3和Bax蛋白表达;ELISA测定肝组织内丙醛(MDA)含量和超氧化物歧化酶(SOD)活性。结果与对照组相比,D-gal组肝细胞水肿、点状坏死;血清ALT和AST水平升高(P<0.05),SOD活性降低、MDA含量升高(P<0.05);Bax、caspase-3、BDNF、TrkB表达增加(P<0.05),Bcl-2表达降低(P<0.05);与D-gal组相比,BPS各剂量组肝细胞变性、坏死明显减轻;血清ALT和AST水平降低(P<0.05);SOD活性升高、MDA含量降低(P<0.05);促凋亡蛋白Bax和caspase-3表达降低,抗凋亡蛋白Bcl-2表达增加(P<0.05);BDNF和TrkB的表达降低(P<0.05)。结论BPS对D-gal所致实验性肝损伤有一定的保护作用,其机制可能与降低肝组织内BDNF和TrkB的表达、减轻肝细胞凋亡有关。

Objective To study the effects of Balanophora polysaccharides(BPS)on the expression of BDNF,TrkB and other apoptosis-related proteins in rats with experimental liver injury induced by D-gal.MethodsRats were randomly divided into control group,D-gal group(200 mg/kg of hypodermic D-galactose),groups with BPS of low dosage(BPS-L),medium dosage(BPS-M)and high dosage(BPS-H),which were treated with intragastric administration by 50,100 and 200 mg/kg BPS per day,respectively.After six weeks,serum alanine transaminase(ALT)and aspartate aminotransferase(AST)were measured.HE staining was used to observe liver tissue morphology.The localization of BDNF and TrkB was determined by immuno-histochemical staining.Western blot was used to detect BDNF,TrkB,Bcl-2,caspase-3 and Bax protein expression.ELISA was used to determine the malondialdehyde(MDA)content and superoxide dismutase(SOD)activity in liver tissues.Results Compared with the control group,the hepatocytes showed edema and punctate necrosis in D-gal group,with increased serum level of ALT and AST(P<0.05).The results also showed decreased SOD activity and increased MDA content(P<0.05),increased Bax,caspase-3,BDNF,TrkB expression(P<0.05)and decreased Bcl-2 expression(P<0.05).Compared to D-gal group,the hepatocyte degeneration and necrosis were obviously alleviated in BPS groups with each dose accompanied by decreased serum ALT and AST levels(P<0.05),increased SOD activity and decreased MDA content(P<0.05),reduced Bax and caspase-3 expression of pro-apoptotic proteins,increased expression Bcl-2 anti-apoptotic proteins(P<0.05)and decreased expression of BDNF and TrkB(P<0.05).Conclusions Balanophora polysaccharide had a protective effect on experimental liver injury caused by D-gal.The mechanism may be related to the decrease of the expression of BDNF and TrkB followed by inhibition of hepatocyte apoptosis.