目的:观察血管活性肠肽(vasoactive intestinal peptide,VIP)对便秘大鼠肠道水液代谢、环磷酸腺苷-蛋白激酶A信号通路(cyclic AMP protein kinase A signaling pathway,c AMP-PKA)和水通道蛋白3(water channel protein 3,AQP3)的影响,探...目的:观察血管活性肠肽(vasoactive intestinal peptide,VIP)对便秘大鼠肠道水液代谢、环磷酸腺苷-蛋白激酶A信号通路(cyclic AMP protein kinase A signaling pathway,c AMP-PKA)和水通道蛋白3(water channel protein 3,AQP3)的影响,探讨VIP治疗便秘的作用及机制。方法:45只健康成年Sprague-Dawley大鼠随机分为空白对照组、模型组、模型+VIP组。给药4周后,墨汁灌胃法检测大鼠首粒黑便排出时间;根据大鼠粪便干湿重计算粪便含水率;HE染色观察各组大鼠结肠组织形态学变化;Western印迹检测各组大鼠结肠组织中VIP和AQP3蛋白表达水平;定量即时聚合酶链锁反应(quantitative real time polymerase chain reaction,q PCR)检测各组大鼠结肠组织中c AMP,PKA和AQP3 m RNA的表达水平。结果:与空白对照组比较,模型组大鼠首粒黑便出现时间延长,粪便含水率明显减少(均P<0.01);结肠黏膜上皮部分破坏,杯状细胞体积减小,数量明显减少;结肠组织中VIP和AQP3蛋白含量明显减少,AQP3,c AMP和PKA m RNA相对表达水平均有所降低(均P<0.05)。与模型组比较,模型+VIP组大鼠首粒黑便出现时间缩短,粪便含水率明显增加(均P<0.05);结肠黏膜上皮完整性明显改善,杯状细胞体积增大,数量增多;结肠组织中VIP和AQP3蛋白含量增多,CAMP,PKA和AQP3 m RNA相对表达水平升高(均P<0.05)。结论:VIP静脉注射能够调节肠道水液代谢,改善大鼠便秘症状,其机制可能与调节VIP-c AMP-PKA-AQP3信号通路有关。展开更多
Docosahexaenoic acid(DHA)is a biologically active fatty acid that reduces the accumulation of lipids.However,the molecular mechanism underlying this process,particularly in fish,is not well understood.Recent studies s...Docosahexaenoic acid(DHA)is a biologically active fatty acid that reduces the accumulation of lipids.However,the molecular mechanism underlying this process,particularly in fish,is not well understood.Recent studies show that endoplasmic reticulum(ER)stress triggers the activation of the unfolded protein response,which has been revealed to play an essential role in lipid metabolism.In this study,we explored the effect of DHA on ER stress and investigated the potential molecular mechanisms underlying DHA-induced adipocyte lipolysis in grass carp(Ctenopharyngodon idella)both in vivo and in vitro.We found that DHA remarkably reduced the triglyceride content,increased the secretion of glycerol,pro-moted lipolysis in adipocytes and evoked ER stress,whereas inhibiting ER stress using 4-phenyl butyric acid(4-PBA)inhibited the effects of DHA(P<0.05).These results implied that ER stress potentially participates in DHA-induced adipocyte lipolysis.Additionally,STF-083010,a specific inositol-requiring enzyme 1a(IRE1a)-inhibitor,attenuated the effects of DHA on lipolysis,demonstrating that IRE1a and X-box binding protein 1 potentially participate in DHA-induced lipolysis.DHA also activated the cyclic adenosine monophosphate(cAMP)-dependent protein kinase A(PKA)pathway by increasing the level of cAMP and activating the PKA enzyme(P<0.05).Nevertheless,H89,a PKA inhibitor,weakened DHA-induced lipolysis by inhibiting the cAMP/PKA signaling pathway.Furthermore,inhibiting ER stress us-ing 4-PBA also inhibited lipolysis and alleviated DHA-induced activation of the cAMP/PKA signaling pathway,suggesting that ER stress may participate in DHA-induced lipolysis through the activation of the cAMP/PKA signaling pathway.Our data illustrate that DHA supplementation can be a promising nutritional strategy for ameliorating lipid accumulation in grass carp.The present study elucidated the molecular mechanism for DHA-induced lipolysis in grass carp adipocytes and emphasized the impor-tance of ER stress and the cAMP/PKA pathway in DHA-induced lipolysis.These results deepen our un-derstanding of ameliorating lipids deposition in freshwater fish by targeting DHA.展开更多
文摘目的:观察血管活性肠肽(vasoactive intestinal peptide,VIP)对便秘大鼠肠道水液代谢、环磷酸腺苷-蛋白激酶A信号通路(cyclic AMP protein kinase A signaling pathway,c AMP-PKA)和水通道蛋白3(water channel protein 3,AQP3)的影响,探讨VIP治疗便秘的作用及机制。方法:45只健康成年Sprague-Dawley大鼠随机分为空白对照组、模型组、模型+VIP组。给药4周后,墨汁灌胃法检测大鼠首粒黑便排出时间;根据大鼠粪便干湿重计算粪便含水率;HE染色观察各组大鼠结肠组织形态学变化;Western印迹检测各组大鼠结肠组织中VIP和AQP3蛋白表达水平;定量即时聚合酶链锁反应(quantitative real time polymerase chain reaction,q PCR)检测各组大鼠结肠组织中c AMP,PKA和AQP3 m RNA的表达水平。结果:与空白对照组比较,模型组大鼠首粒黑便出现时间延长,粪便含水率明显减少(均P<0.01);结肠黏膜上皮部分破坏,杯状细胞体积减小,数量明显减少;结肠组织中VIP和AQP3蛋白含量明显减少,AQP3,c AMP和PKA m RNA相对表达水平均有所降低(均P<0.05)。与模型组比较,模型+VIP组大鼠首粒黑便出现时间缩短,粪便含水率明显增加(均P<0.05);结肠黏膜上皮完整性明显改善,杯状细胞体积增大,数量增多;结肠组织中VIP和AQP3蛋白含量增多,CAMP,PKA和AQP3 m RNA相对表达水平升高(均P<0.05)。结论:VIP静脉注射能够调节肠道水液代谢,改善大鼠便秘症状,其机制可能与调节VIP-c AMP-PKA-AQP3信号通路有关。
基金supported by the National Nature Science Foundation of China(NSFC,Grant Number:31772863,32072989).
文摘Docosahexaenoic acid(DHA)is a biologically active fatty acid that reduces the accumulation of lipids.However,the molecular mechanism underlying this process,particularly in fish,is not well understood.Recent studies show that endoplasmic reticulum(ER)stress triggers the activation of the unfolded protein response,which has been revealed to play an essential role in lipid metabolism.In this study,we explored the effect of DHA on ER stress and investigated the potential molecular mechanisms underlying DHA-induced adipocyte lipolysis in grass carp(Ctenopharyngodon idella)both in vivo and in vitro.We found that DHA remarkably reduced the triglyceride content,increased the secretion of glycerol,pro-moted lipolysis in adipocytes and evoked ER stress,whereas inhibiting ER stress using 4-phenyl butyric acid(4-PBA)inhibited the effects of DHA(P<0.05).These results implied that ER stress potentially participates in DHA-induced adipocyte lipolysis.Additionally,STF-083010,a specific inositol-requiring enzyme 1a(IRE1a)-inhibitor,attenuated the effects of DHA on lipolysis,demonstrating that IRE1a and X-box binding protein 1 potentially participate in DHA-induced lipolysis.DHA also activated the cyclic adenosine monophosphate(cAMP)-dependent protein kinase A(PKA)pathway by increasing the level of cAMP and activating the PKA enzyme(P<0.05).Nevertheless,H89,a PKA inhibitor,weakened DHA-induced lipolysis by inhibiting the cAMP/PKA signaling pathway.Furthermore,inhibiting ER stress us-ing 4-PBA also inhibited lipolysis and alleviated DHA-induced activation of the cAMP/PKA signaling pathway,suggesting that ER stress may participate in DHA-induced lipolysis through the activation of the cAMP/PKA signaling pathway.Our data illustrate that DHA supplementation can be a promising nutritional strategy for ameliorating lipid accumulation in grass carp.The present study elucidated the molecular mechanism for DHA-induced lipolysis in grass carp adipocytes and emphasized the impor-tance of ER stress and the cAMP/PKA pathway in DHA-induced lipolysis.These results deepen our un-derstanding of ameliorating lipids deposition in freshwater fish by targeting DHA.
