洛美利嗪对糖尿病早期大鼠视网膜神经节细胞的保护作用

目的： 探讨洛美利嗪(lomerizine，LOM)对糖尿病早期大鼠视网膜神经节细胞(retinal ganglion cells，RGCs)凋亡的保护作用及其机制。

方法： SD大鼠随机分为对照组(CON)、糖尿病组(DM)及洛美利嗪组(LOM)，每组40只大鼠。DM和LOM组链脲佐菌素(STZ)按60mg/kg一次性腹腔注射诱导糖尿病模型，CON组给予等量无菌柠檬酸钠溶液腹腔注射。LOM组于糖尿病鼠模型成模后，每日予LOM 60mg/kg灌胃，CON组和DM组采用等量生理盐水灌胃。于第4，8，12wk分别行HE、透射电镜、TUNEL检测RGCs的凋亡情况，同时采用激光共聚焦显微镜检测RGCs内钙离子的浓度。

结果：(1)形态学观察：随病程延长，逐渐出现RGCs数量减少、细胞排列紊乱的病理改变。透射电镜下可见DM组RGCs出现不同阶段的凋亡征象，且随病程延长逐渐加重。LOM组与同期DM组对比，在第8，12wk时RGCs凋亡征象减弱。(2)TUNEL检测：CON组大鼠视网膜神经节细胞层未见凋亡细胞。DM组4wk时视网膜神经节细胞层偶见TUNEL 阳性细胞，并随病程延长逐渐增多，凋亡指数与同期CON组比较明显升高，差异有统计学意义(P<0.01)。LOM 组8，12wk时，与同期DM组比较，染色阳性的RGCs明显减少，凋亡指数明显下降，差异显著(P<0.01)。(3)激光共聚焦显微镜钙离子浓度检测：DM组与同期CON组比较：DM组8，12wk 的RGCs内钙离子荧光染色强度明显升高，有显著差异(P<0.01)。LOM组与同期DM组比较：LOM 组8，12wk的RGCs内钙离子荧光染色强度明显下降，差异有统计学意义(P<0.01)。

结论：LOM对糖尿病大鼠早期RGCs的凋亡具有保护作用。

Protective effects of lomerizine on retinal ganglion cells in early diabetic rats

AIM: To investigate the neuroprotection of lomerizine(LOM)on retinal ganglion cells(RGCs)in early diabetic rats and their mechanism.

METHODS: Adult male Spraque - Dawley(SD)rats were randomly divided into control(CON), diabetes mellitus(DM), lomerizine(LOM)group, and each group had 40 rats. Diabetes rat model was induced by Streptozotocin(STZ)of intraperitoneal injection of 60 mg/kg of disposable. In LOM group, after model was established, rats were lavaged LOM by the dosage of 60mg/kg daily, the CON group and DM group were given the same dosage sodium chloride. In 4^th, 8^th, 12^th wk, RGCs' apoptosis were detected by HE, TUNEL, transmission electron microscope, and TUNEL and laser confocal microscope detection was used to test the calcium ion concentration.

RESULTS: Morphological observation: with the extension of the DM, RGCs decreased gradually and appeared disordered arrangement of cells. In DM group, different stages of apoptosis were observed by transmission electron microscope and got worse gradually with its extension. In LOM group, compared with DM group in the same period, RGCs apoptosis signs diminished gradually at 8^th and 12^th wk. TUNEL detection: no apoptotic RGCs was observed in CON group. In DM group, few TUNEL positive RGCs were seen at 4^th wk, and became more and more gradually. The apoptosis index was significantly higher in DM group compared with CON group in same time and there was statistical significance(P<0.01). In LOM group at 8^th and 12^th wk, compared with DM group in the same period, the numbers of TUNEL positive RGCs decreased. The apoptosis index was significantly lower in LOM group compared with DM group in the same period(P<0.01). Calcium ion concentration detection by laser confocal microscope: compared with CON group in same time points, at 8^th and 12^th week, DM group's calcium fluorescent staining intensity of RGCs markedly elevated and had significant differences.(P<0.01). In LOM group, at 8^th and 12^th wk, calcium fluorescent staining intensity of RGCs markedly decreased and had statistical significance(P<0.01).

CONCLUSION: The LOM played a protective role for RGCs in early stage of diabetic rats.