碱性成纤维细胞生长因子对谷氨酸毒性损伤豚鼠视网膜内生长抑素表达的影响

为了探讨过量谷氨酸毒性损伤豚鼠视网膜内生长抑素(SOM)的表达及碱性成纤维细胞生长因子(bFGF)对其表达的影响,本实验将豚鼠随机分成三组。损伤组:腹膜腔内给予谷氨酸钠3g/kg,隔天给药,连续7d;对照组:采用相同方法注射等量生理盐水;治疗组(bFGF+谷氨酸钠):在注射谷氨酸钠之前1~2h,给予bFGF800U/kg,隔天给药,连续7d。各组动物分别在存活10d后取材。采用免疫组织化学和图像分析技术,对各组豚鼠视网膜内SOM样免疫反应产物的表达进行检测。结果显示:(1)正常豚鼠视网膜内可观察到许多SOM样免疫阳性神经元,这些神经元主要分布于视网膜节细胞层(GCL)和内核层(INL);(2)损伤组相应区域内可观察到SOM样阳性细胞数较对照组明显减少(P<0.05或P<0.01),其染色强度亦明显减弱;(3)治疗组经预先给予bFGF后,在GCL和INL内可检测到SOM样阳性细胞数较损伤组明显增加(P<0.05或P<0.01),其染色强度有所增强。以上结果提示:过量谷氨酸钠可导致视网膜内SOM的表达显著降低,而bFGF则可以上调由于过量谷氨酸毒性损伤所引起的SOM的表达。

THE EFFECTS OF BASIC FIBROBLAST GROWTH FACTOR ON EXPRESSION OF SOMATOSTATIN IN THE GUINEA PIG RETINA AFTER SUPERABUNDANT GLUTAMATE INJURY

To investigate the effects of basic fibroblast growth factor (bFGF) on expression of somatostatin (SOM) in the guinea pig retina after superabundant glutamate injury, the guinea pigs were randomly divided into three groups in the present study. Model group was given the glutamate (3 g/kg) by intraperitoneal injection (i.p) and every other day, for 7 days; normal control group accepted equivalent saline using same methods as the model group; treatment groups received bFGF (800 U/kg, i.p) before 1~2 hours of glutamate injection, for 7 days. At 10 days after injection, all guinea pig were killed and the expression of SOM-like immunoreactivity in retina was detected by using immunohistochemical method and image analysis system. The results showed: (1) SOM-like immunoreactive neurons were observed in retina of normal control group. Those SOM-positive cells distributed mainly in the ganglion cell layer (GCL) and inner nucleus layer (INL) of retina; (2)The number of SOM-positive cells was checked to obviously reduce in retina of model animals comparing with normal control group(P<0.05 or P<0.01)and the density of SOM-immunostaining declined; (3)Number of SOM-positive cells was obviously increased in GCL and INL of retina in treatment groups received bFGF injection beforehand comparing with the model animals(P<0.05 or P<0.01)and the density of SOM-immunostaining elevated. The present results suggest that superabundant glutamate give rise to reduced expression of SOM, bFGF can up-regulate the expression of SOM in retina after injury by the superabundant glutamate.