目的 观察新型可降解镁合金支架-MPM在兔腹主动脉降解过程中对血管内膜的影响.方法 新西兰大白兔12只,分为4组,每组3只,每只兔子腹主动脉距肾动脉水平下1cm处置入可吸收金属镁合金支架-MPM 1枚,于术后1个月(30天)、2个月(60天)、3个月(90天)及6个月(180天),分别对1组实验动物支架段血管进行病理切片,对其内膜面积、管腔面积及免疫组化PCNA阳性细胞光密度值进行统计分析.结果 1个月、2个月、3个月及6个月时支架内膜面积分别为(0.87±0.6)mm2、(0.73±0.33)mm2、(1.38±0.47)mm2、(0.85±0.23)mm2,各个时间终点剩余管腔面积分别为(2.11±0.41)mm2、(1.85±0.44)mm2、(1.38±0.31)mm2、(1.86±0.43)mm2,光镜下观察支架植入后,内膜逐渐增生,其增厚呈现出不均一性,3个月时内膜增生为著(P<0.05),管腔剩余面积与内膜增厚呈现一致性,免疫组化PCNA阳性细胞数的平均光密度值显示第3个月时为0.00917±0.0025,相比其他对照组有统计学差异(P<0.05),进一步验证了内膜增生、管腔狭窄在3个月时达到高峰,随之当支架降解完全后,增生减少,血管内膜出现正性重塑.结论 可降解镁合金支架MPM在兔主动脉降解过程中不同时间会对血管内膜产生不同程度的内膜增生反应及管腔狭窄,其中以3个月(90天)时间时为著,此后增生有逐渐减少的趋势.%Objective To observe the characteristics of vascular neointima and lumen area of MPM bioabsorbable magnesium alloy stent after being implanted in the abdominal aorta of experimental rabbits .Methods Totally, twelve new zealand white rab-bits were randomly and equally divided into 4 groups according to the postoperative time (1, 2, 3 and 6 months after stent implan-tation).Each of them were implanted a MPM absorbable magnesium alloy stent one centimeter below renal artery in abdominal a -ortas respectively , and then, stent segments of the arteries of every group were removed for the pathological observation and analy -sis at 1, 2, 3 and 6 months after stent implantation , which included the area of intima and lumen results were observed by HE staining and the number of PCNA-positive cells were observed by immunohistochemistry .Results The area of neointima intimal was (0.87 ±0.60) mm2 , (0.73 ±0.33) mm2 , (1.38 ±0.47) mm2 and (0.85 ±0.23) mm2 respectively after one month (30 days), two months (60 days), three months (90 days) and six months (180 days).And the corresponding residual lumen area was (2.11 ±0.41) mm2, (1.85 ±0.44) mm2, (1.38 ±0.31) mm2 and (1.86 ±0.43) mm2 respectively.The microscope showed that the vascular intima became irregularly thicken .Data of our research suggested that neointima hyperplasia was statisti-cally significant in the third month group compared with other groups ( P <0.05), just as well as the residual lumen area .Immu-nohistochemistry showed that mean integral optical density of PCNA-positive cells (0.00917 ±0.0025) was statistically significant compared with other groups after 3 months ( P <0.05), which further demonstrated that intimal hyperplasia and angiostenosis reached a peak at the third month after stent insertion , and then the neointima hyperplasia became slow and remold by the time of complete degradation of the stent .Conclusion The MPM magnesium stent could induce neointimal proliferation and lead to an-giostenosis before total degradation , especially the third month after stent placement .Neointimal proliferation and angiostenosis would gradually go slow after 3 months.
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