老年大鼠损伤血管过度增殖与内皮Jagged1表达的关系

目的 探讨增龄促进大鼠损伤血管过度增殖与内皮Jaggedl表达的关系. 方法 健康雄性SD大鼠(幼年3月龄.老年22月龄)40只随机分为对照组和胸主动脉球囊损伤组各20只,胸主动脉球囊损伤组分别于术后,术后7、14、28 d(每个时间点老年与幼年组分别为5只)取靶血管行免疫组化染色观察内皮Jaggedl和新生内膜增殖细胞核抗原(PCNA)的动态变化,计算28 d时新生内膜与中膜比值.培养大鼠主动脉内皮和平滑肌细胞,用流式细胞法分析年龄对内皮Jaggedl表达率的影响.并将内皮接种于下室、平滑肌和上室建立共培养体系,用3H-TdR掺人和平滑肌迁移计数检测不同月龄大鼠内皮对血小板源生长因子(PDGF)刺激的平滑肌增生迁移的影响. 结果 老年大鼠新生内膜与中膜比值明显高于幼年大鼠(分别为0.35±0.02与0.28±0.01.,P＜0.01);与幼年大鼠比较,老年大鼠再生内皮Jagged1呈上调延迟并迅速下降的变化模式,而PCNA升高幅度大、维持时间长;流式细胞分析结果 表明,老年大鼠内皮Jaggedl表达率(46.6±6.3)%·低于幼年大鼠的(85.4±4.0)%,P＜0.05;PDGF(10 ng/ml)能显著促进幼年和老年内皮组平滑肌细胞增生迁移,但与老年大鼠内皮共培养的平滑肌增生迁移更明显3H-TdR掺入:(26 438±1857)cpm/孔与(16 698±2076)cpm/孔,P＜0.05;迁移:(32±4)个/高倍视野与(18±5)个/高倍视野,P＜0.05]结论 老年大鼠血管损伤后内皮Jaggedl上调障碍,与老龄促进平滑肌增生迁移密切相关,提示Jagged1可能参与了老龄加重损伤血管过度增殖的调控.

Relationship between aging-induced neointima formation and Jagged1 dynamic expression in regenerating endothelial cells after arterial injury in rats

Objective To investigate the relationship between aging-induced neointimal formation and Jagged 1 dynamic expression in endothelium after arterial injury in rats. Methods Forty healthy male Sprague-Dawley rats aged 3 months (young adult) and 22 months (old) were selected, and thirty of them were subjected to balloon catheter injury at the thoracic aorta. Morphometry analysis was applied to evaluate neointima/media ratio at 28 days after arterial injury. Immunohistochemistry was used to observe the dynamic expressions of Jaggedl in endothelium and the proliferating cell nuclear antigen (PCNA) in neointima at 7 days, 14 days and 28 days after arterial injury respectively. Cell co-culture system was developed by inoculating endothelial cells(EC) in the upper chamber and smooth musele eells(SMC) in the lower chamber. Fluorescence activated cell sorter (FACS) was used to assay the effect of aging on the expression of Jagged 1 in EC. ＜'3＞H-TdR incorporation and cells counting were used to determine the influence of EC of different ages of rats on platelet derived growth factor (PDGF)-induced proliferation and migration of SMC. Results The neointima/media ratio were obviously higher in old rats than in young rats (0.35±0.02 vs. 0.28±0.01, n=5, P＜0.01). Compared with the young counterparts, old rats showed in immunohistochemistry that the Jaggedl in endothelium displayed a delayed up-regulation and quickly diminished evolvement pattern. The maximal enhancing level of Jaggedl in old rats was much lower than that in young ones. However, the increased extent of PCNA in neointima was significantly higher in old rats than that in young ones. Jagged 1 expression in EC in old rats was significantly lower than that in young one(46.6±6.3)% vs. (85.4±4.0)%,n=3, P＜0.05]. The SMC co-cultured with EC in old rats exhibited higher proliferation and migration capability than those in young ones after exposure to PDGF of 10ng/ml2H-TdR incorporation: (26 438±1857) cpm/well vs. (16 698±2076)cpm/well, n=5, P＜0.05. migration:(32±4) cells/field vs. (18±5) cells/field, n=5, P＜0. 05]Conclusions The up-regulation of Jaggedl in EC is impaired in aged rats, which is closely related to aging-indueed SMC proliferation and migration. It also suggests that Jagged1 might be involved in the process of aging-exaggerated neointima formation.