视网膜缺血再灌注损伤的机制及bFGF对其干预作用

目的探讨碱性成纤维细胞生长因子(basic fibric growth factor;bFGF)在大鼠视网膜缺血再灌注损伤(retina ischemi—a/reperfusion injury;RIRI)中治疗作用及机制。方法采用升高眼内压的方法建立大鼠视网膜缺血-再灌注模型,并将48只大鼠随机分为正常组、缺血组、治疗组。在再灌注后1、6、12、24、72h时段分别应用末端脱氧核酸转移酶介导的脱氧三磷酸尿苷缺口末端标记法(TUNEL)检测视网膜组织中凋亡细胞的表达,采用过氧化物酶标记的链酶卵白素(streptavidin perox—idase,SP)免疫组化方法检测caspase-3的表达,使用原子吸收光度计测定细胞内钙离子的变化。结果在大鼠RIRI中,缺血组凋亡细胞在再灌注6h组开始出现,以后时段依次递增,至24h达到高峰,于72h已无明显表达。Caspase-3表达改变与凋亡细胞表达相似。钙离子于再灌注后1h开始升高,至24h达到高峰,72h出现下降。而在bFGF治疗组各观察指标变化规律基本同上,但各指标与缺血组相比较均下降,于再灌注6、12、24h时段两者差别具有统计学意义。结论细胞凋亡可能在视网膜缺血再灌注损伤中起到重要作用,bFGF可通过对细胞内钙离子、自由基以及凋亡蛋白表达的调控而达到对细胞凋亡的抑制,并进而达到对视网膜缺血再灌注损伤的治疗作用。

Mechanisms of retina/reperfusion injury and interference of bFGF in it

Aim To investigate the therapeutical effect and mechanisms of basic fibric growth factor (bFGF) on retina ischemia/ reperfusion injury. Methods Experimental retinal ischemia/ reperfusion injury was induced by increasing intraocular pressure in the eyes of rats. 48 rats were randomly divided into groups of normal control, ischemia/ reperfusion and bFGF-treated. Apoptotic cells were detected using the TdT-dUTP terminal nick-end labeling (TUNEL) method at 1, 6, 12, 24, 72h after reperfusion. The expression of cas-pase-3 of different time courses was determined by Streptavidin Peroxidase (SP) immunohistochemistry. Atomic absorption spectrum method was taken to evaluate the inner cellular calcium changes of retina tissues. Results In ischemia group apoptotic cells began to appear at 6th hour after reperfusion and increased progressively as the time courses prolonged. The number of apoptotic cells reached the peak at 24h after reperfusion, and at 72h no apoptotic cells could be found. The change trend of caspase-3 expression was similar: the intracellular calcium level of rat retina began to increase at Ih after reperfusion, and went on increasing with the reperfusion time prolonged. At 24h after reperfusion the intracellular calcium level reached the peak, and began to decease at 72h. The change trends of the three markers of treatment group were similar to the above, but they were all relatively less. There were statistical significance (P<0. 05) between the ischemia group and treatment group at 6, 12, and 24h after reperfusion. Conclusion Apoptosis may play a vital role in retina ischemia-reperfusion injury. bFGF may has a therapeutical effect on retina ischemia-reperfusion injury by inhibiting the increase of retina intracellular calciums and caspase-3 protein expression.