褪黑素对热应激猪精子质量的影响

为研究褪黑素(Melatonin,MLT)对热应激引起的猪精子质量下降的缓解作用及其机制。首先用免疫荧光方法检测MLT受体在猪精子上的存在和分布;然后将稀释后的精子分为对照组(ck)、热应激组(H)、MLT组(M)、热应激+MLT组(H+M)、热应激+MLT受体拮抗剂Luzindole组(H+L)和热应激+MLT受体拮抗剂Luzindole+MLT组(H+L+M)6个组,处理结束后检测各组精子活率、活力、线粒体活性、钙离子水平以及顶体完整率。结果显示:猪精子中存在MLT受体MT1和MT2,且均分布于精子头部;与对照组相比热应激组各项指标显著下降,MLT组精子活率没有显著改变(P0.05),但精子活力、线粒体活性、钙离子水平和顶体完整率显著升高(P0.05)。添加MLT受体拮抗剂Luzindole后精子活力、线粒体活性和钙离子水平显著下降(P0.05),顶体完整率呈一定程度下降,但差异不显著(P0.05)。以上结果表明:热应激会导致猪精子质量显著下降,并且MLT能通过受体途径改善热应激对猪精子质量的影响,但同时也存在非受体介导的作用。

Effect of Melatonin on Sperm Quality of Heat Stressed Boar

The aim of this study is to investigate the alleviation effect of the melatonin (MLT) on influence of heat stress on sperm quality and its mechanism.We firstly detected the existence and distribution of MLT receptors MT1 and MT2 in boar sperm via immunofluorescence analysis.Then we divided the diluted fresh boar sperm into six groups:control group (C),MLT treated group (M),heat stressed group (H),co-treated with heat stress and MLT group (H+M),co-treated with heat stress and luzindole group (H+L),and co-treated with heat stress,luzindole and MLT group (H+L +M).Then we detected sperm viability,motility,mitochondrial activity,calcium concentration and acrosome integrity.The results showed that heat stress significantly reduced the quality of sperm,and MLT did not significantly (P＞0.05) improve the sperm viability of the heat stressed boar,but significantly enhanced motility,mitochondrial activity,calcium level and acrosomal integrity.Moreover,luzindole treatment could attenuate these effects of MLT to some degree via blocking its receptor.These results suggested that heat stress impaired boar sperm quality and administration of MLT to heat stressed sperm alleviate the adverse effect of heat stress via receptor mediated and non-receptor mediated action.