模拟失重大鼠胸主动脉平滑肌细胞凋亡的变化及间断性人工重力对抗的影响

目的:观察模拟失重大鼠胸主动脉平滑肌细胞凋亡的变化及间断性人工重力对其影响。方法: 将27只SD大鼠随机分为3组（每组9只），即对照组(CON)、模拟失重组(SUS)及站立对抗组(STD)。以尾部悬吊大鼠模拟失重3周，同期每天悬吊23 h、站立1 h模拟间断性人工重力对抗的效果。用TUNEL染色法检测SUS组、同步对照(CON)组及STD组大鼠胸主动脉平滑肌细胞的凋亡情况；用Western blot法检测各组大鼠胸主动脉组织中Bad、FasL及Caspase-3蛋白表达的变化。结果: 与CON组比较，SUS组大鼠胸主动脉平滑肌细胞TUNEL染色阳性的细胞明显减少(P<0.01)；STD组TUNEL染色阳性的细胞较CON组及SUS组显著增加（P<0.01）。SUS组Bad的表达较CON组和STD组显著减少（P<0.05），STD组Bad的表达较CON组有增加的趋势，但无统计学差异。SUS组FasL及Caspase-3的表达较CON组显著降低(P<0.05)；STD组FasL及Caspase-3的表达较CON组及SUS组显著增高(P<0.01)。结论: 模拟失重可减少大鼠胸主动脉平滑肌细胞凋亡，每日1 h的-Gx对抗可使胸主动脉平滑肌细胞的凋亡增加，提示血管组织平滑肌细胞的凋亡在失重引起的动脉血管适应性重构中可能发挥重要作用。

Effects of 3-week simulated microgravity and intermittent artificial gravity on apoptosis of thoracic aortic smooth muscle cells in rats

AIM: To investigate the effects of 3-week simulated microgravity and intermittent artificial gravity on apoptosis of thoracic aortic smooth muscle cells(TASMCs) in rats.METHODS: Twenty seven Sprague Dawley rats were randomly divided into three groups with nine rats in each group: control group(CON),tail-suspended group(SUS) and standing group(STD).SUS rats were used to simulate the effects of microgravity and homochronous countermeasure(STD,daily 1 h of-Gx gravitation) was used to simulate the effects of intermittent artificial gravity(IAG).Apoptosis of TASMCs was assessed by TUNEL staining,and protein expressions of Bad,FasL and Caspase-3 in thoracic aorta tissues were observed by Western blot.RESULTS: Compared with those in control(CON) group,TUNEL-positive TASMCs in STD increased significantly(P<0.01),and TUNEL positive TASMCs in SUS rats decreased significantly(P<0.01) compared with those in both CON group and SUS group.Compared with that in CON group and STD group,protein expression of Bad in the SUS group significantly decreased(P<0.05).Expression of Bad displayed an increasing tendency in STD group compared with that in the CON group,but without a significant difference.Compared with those in the CON group,protein expressions of either FasL or Caspase-3 in the SUS group decreased significantly(P<0.05),respectively,but expressions of both FasL and Caspase-3 in STD group increased significantly(P<0.01),respectively,compared with those in either the CON or SUS group.CONCLUSION: Decrease of apoptosis of TASMCs can be induced by simulated microgravity,whereas intermittent artificial gravity may cause the increase of apoptosis of TASMCs.These findings further suggest that apoptosis of vascular smooth muscle cells may play an important role in the adaptive remodeling of vessels induced by microgravity.