运动对高脂膳食大鼠肝脏血小板活化因子代谢的影响

The effect of exercise on platelet-activating factor metabolism in the livers of rats fed high-fat diet

本文旨在探讨高脂膳食和/或运动对肝脏血小板活化因子(platelet-activating factor,PAF)的影响及可能的机制。将32只雄性Sprague-Dawley(SD)大鼠随机分为对照组(control,C)、高脂膳食组(high-fat diet,H)、运动组(exercise,EC)和高脂膳食+运动组(high-fat diet+exercise,EH),16周的膳食和/或运动干预后取血清测定血脂和肝损伤标记物,取肝组织采用液相色谱/质谱进行脂质组学分析,通过qPCR和Western blot测定PAF代谢相关酶的基因和蛋白表达。结果显示:(1)高脂膳食显著增加了大鼠低密度脂蛋白胆固醇(low-density lipoprotein-cholesterol,LDL-C)、以及嘌呤核苷酸磷酸化酶(purine nucleoside phosphorylase,PNP)和丙二醛(malondialdehyde,MDA)等肝损伤标记物含量,运动则降低了这些指标;(2)高脂膳食显著增加了肝脏PAF含量,运动缓解了由高脂膳食引起的这种变化;(3)高脂膳食导致PAF关键合成酶PAF-CPT蛋白表达及磷脂酶A2(phospholipase A2,PLA2)基因和蛋白表达增加,水解酶Lp-PLA2基因和蛋白表达及PAF-AH(Ⅱ)蛋白表达也增加,但合成酶增加程度显著高于水解酶;运动则增加了Lp-PLA2和PAF-AH(Ⅱ)蛋白表达并减少了PAF关键合成酶PAF-CPT和PLA2的蛋白表达。综上所述,高脂膳食诱导PAF含量增加的可能机制主要是在翻译水平增加其病理性合成,而运动则通过增加PAF水解和减少其合成两方面降低高脂膳食大鼠肝脏PAF含量。

This paper aimed to investigate the effects of exercise on hepatic platelet-activating factor(PAF)metabolism in rats fed a high-fat diet.Thirty-two male Sprague-Dawley(SD)rats were divided into control group(C),high-fat diet group(H),exercise group(EC),and high-fat diet+exercise group(EH).Serum lipids,glucose,insulin and markers of hepatic injury after a 16-week dietary and/or exercise intervention(60 min/day,6 times/week)were measured by biochemical analysis;liver lipidomic profiles were analyzed by liquid chromatograph-mass spectrometer(LC-MS).Gene and protein expression of enzymes related to PAF metabolism were determined by qPCR and Western blot respectively.The results showed that high-fat diet feeding significantly increased the levels of low-density lipoprotein-cholesterol(LDL-C)and liver injury markers including purine nucleoside phosphorylase(PNP)and malondialdehyde(MDA)in rats,which were decreased by exercise.Furthermore,high-fat diet feeding significantly increased the hepatic PAF content,which was also attenuated by exercise.In addition,although high-fat diet treatment resulted in an increase in the expression of both PAF synthetase(PAF-CPT and PLA2)and hydrolase(Lp-PLA2 and PAF-AH(Ⅱ)),induction of PAF synthetase was much greater than that of PAF hydrolase.While exercise increased the expression of Lp-PLA2 and PAF-AH(Ⅱ)and decreased the expression of PAF-CPT and PLA2,key PAF synthesizing enzymes.In conclusion,high-fat diet-induced increase in hepatic PAF content is mainly due to the increase of its pathological synthesis at the translational level.Exercise reduces hepatic PAF content in high-fat fed rats by increasing PAF hydrolysis and decreasing its synthesis.