重复、长时间正加速度对动脉粥样硬化家兔模型血管内分泌功能的影响

Effect of repeated and prolonged +Gz exposure on endocrine function of vessel in a rabbit model of atherosclerosis

目的观察重复、长时间正加速度(+Gz)对动脉粥样硬化家兔模型血管内分泌功能的影响。方法健康雄性新西兰白兔24只,建立动脉粥样硬化模型后随机分为对照组(不进行+Gz暴露,n=12)和+Gz暴露组(n=12)。分别于4、8、12周后处死两组动物(每个时间点4只),采用放射免疫及生物化学法测定静脉血的血管紧张素Ⅱ(AngⅡ)、内皮素(ET)含量及血管内皮细胞的血红素氧化酶-1(HO-1)活力、内源性一氧化碳(CO)浓度及环磷酸鸟苷(cGMP)含量,并对主动脉内膜进行电镜观察。结果随+Gz暴露时间的延长,实验室兔静脉血AngⅡ、ET及血管内皮细胞HO-1、CO、cGMP含量均显著增高(P<0.05),但暴露至第12周时已不再增加;对照组上述指标无明显变化(P=0.05)。对照组动脉内膜下及中膜浅层的泡沫细胞及胶原含量仅见少量增加,而+Gz暴露8、12周后主动脉内膜下及中膜浅层可见大量增生的泡沫细胞,间质胶原纤维含量明显增加。结论重复、长时间+Gz暴露会诱发AngⅡ和ET的产生,但也会增加HO-1、CO、cGMP的分泌,对血管免受进一步损伤可能具有潜在的保护作用。

Objective To investigate the effect of repeated and prolonged ＋Gz exposure on endocrine function of vessel in a rabbit model of atherosclerosis.Methods Twenty-four male New Zealand white rabbits were used to establish the model of atherosclerosis,and then randomly divided into control group and ＋Gz exposure group（12 each）.Animals in control group underwent no ＋Gz exposure,while those in ＋Gz exposure group underwent ＋Gz exposure for 4,8,and 12 weeks respectively（4 animals at each time point）,and 4 animals from each group were sacrificed at each time point.The levels of angiotensin Ⅱ（Ang Ⅱ）,endothelin（ET）,heme oxygenase-1（HO-1）,carbon monoxide（CO） and cyclic guanosine-3’,5’-monophosphate（cGMP） were measured by radioimmunoassay and biochemical method,and the ultrastructure of aortic intima was examined by electron microscopy.Results Along with the prolongation of ＋Gz exposure,the contents of Ang Ⅱ,ET,HO-1,CO and cGMP were increased in ＋Gz exposure group（P〈0.05）,but the increase stopped at the 12th week,and no obvious change in the above indices was observed in control group（P=0.05）.The foam cells and collagen content under the aortic intima and in the shallow layer of aortic media were slightly increased in control group,but the foam cells and the interstitial collagen fibers were greatly increased after ＋Gz exposure for 8 and 12 weeks as compared with that in control group.Conclusion Repeated and prolonged ＋Gz exposure may induce the production of Ang Ⅱ and ET,increase the secretion of HO-1,CO and cGMP,thus play a potential role in protecting the vessels from further injuries.