AIM: To investigate the safety of tissue plasminogen activator (tPA) intra optic nerve injection in rabbits. METHODS: Group 1 and 2 (6 eyes in each group) received injection of tPA 25μg and 12.5μg in 0.1mL balanced saline solution (BSS). Group 3 (6 eyes) received injection of 0 1mL BSS. Six eyes in group four as a normal control received no injection. The eyes were examined with slit lamp biomicroscope, indirect ophthalmoscope, visual evoked potentials (VEP) and electroretinography (ERG) at 1, 3, 7, 14 and 28 days after injection. RESULTS: No evidence of optic nerve or retinal toxicity or physical damage were revealed by ophthalmoscopy, VEP, and ERGs after the injection of tPA into the optic nerve. The means of the latency of the first peak of the VEP were 24.6±1.5, 24.1±1.9, 24.0±2.0 and 24.6±1.3mS respectively for the above specified groups (P=0.4112). The means of the amplitude of the first peak of the VEPs were 124±42, 145±41, 132±48 and 117±29μV respectively (P=0.0649). The means of the latency of a-waves were 6.0±0.4, 5.9±0.4, 5.9±0.5 and 5.8±0.3 mS respectively (P=0.6279). The means of the amplitude of a-waves were 110±14, 112±15, 110±16 and 108±11μV respectively (P=0.7248). The means of the amplitude of b-waves were 151±12, 148±14, 144±16 and 141±20μV respectively (P =0.0957).CONCLUSION: Injection of tPA upto 25μg in 0.1mL into optic nerve is well tolerated.%目的:探讨视盘内注射组织凝血酶原激活剂的电生理学安全性.方法:首先将记录VEP的电极植入兔颅骨内.经兔睫状体扁平部将25μg tPA,12.5μg tPA及BSS注入视神经内0.1mL,并与第四组正常眼作比较(n=6).注入后1,3,7,14和24d行裂隙灯及间接眼底镜检查,记录VEP及ERG.结果:检查未发现视神经内注射tPA对视神经和视网膜有明显的毒性作用和其它损伤.各组VEP第1个波峰的潜伏期分别是24.6±1.5, 24.1±1.9, 24.0±2.0和24.6±1.3mS( P= 0.4112);振幅分别是124±42, 145±41, 132±48和117±29μV(P= 0.0649).各组ERG的a波的潜伏期分别是6.0±0.4, 5.9±0.4, 5.9±0.5和5.8±0.3mS(P= 0.6279);振幅分别是110±14, 112±15, 110±16和108±11μV(P= 0.7248).b波的振幅分别是151±12, 148±14, 144±16和141±20μV(P= 0.0957).结论:经睫状体扁平部向兔视神经内注射tPA,安全可行.
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