c-myc反义寡核苷酸抑制半乳糖性白内障晶状体上皮细胞凋亡的机制

Inhibition of apoptosis induced by galactose by c-myc antisense oligodeoxynucleotide in lens epithelial cells

目的研究c-myc反义寡核苷酸(ASODN)对半乳糖性白内障晶状体上皮细胞(LECs)凋亡的影响。方法将Wistar大鼠按随机数字表法分为生理盐水组、半乳糖组和半乳糖+c-myc ASODN组,每组36只。半乳糖组及半乳糖+c-myc ASODN组每日球后注射0.2mL20%半乳糖,制作大鼠半乳糖性白内障模型,半乳糖+c-mycASODN组球后注射半乳糖4h后加注Lipo-c-myc ASODN复合液0.2mL,隔日1次。分别于给药后7、14、24d处死动物,取出晶状体,检测LECs的凋亡情况,采用TUNEL法检测c-myc ASODN对半乳糖诱导LECs凋亡的影响,透射电镜下观察LECs超微结构的改变。结果各组在7、14、24d的LECs凋亡率比较,差异均有统计学意义(F7days=3418.495,P<0.01;F14days=1137.555,P<0.01;F24days=2198.871,P<0.01);24d时半乳糖组LECs的凋亡率为56.57±3.20,生理盐水组为0.37±0.11,差异有统计学意义(P<0.01);半乳糖+c-myc ASODN组细胞凋亡率为29.35±1.63,较半乳糖组明显降低(P<0.05)。透射电镜下观察发现,半乳糖组可见LECs呈凋亡细胞的早期改变;随着高糖诱导时间的延长,凋亡细胞逐渐增多;生理盐水组几乎未见到凋亡细胞;半乳糖+c-myc ASODN组凋亡细胞数量较同期半乳糖组少。结论在白内障形成过程中半乳糖能诱导LECs凋亡,c-myc ASODN能够抑制半乳糖诱导的LECs凋亡。

Background Various studies demonstrated that the apoptosis of lens epithelial cells（LECs） is associated with the overexpression of the c-myc gene in LECs induced by galactose. Inhibiting the abnormal expression of the c-myc gene in LECs is an effective approach to mitigate the pathogenesis and development of cataract. Objective The goal of this study is to investigate the inhibitory effects of c-myc antisense oligodeoxynueleotide （c-myc ASODN） on the apoptosis of LECs in the eye with galaetose-induced cataract. Methods Galaetose-induced cataract models were established by the retrobulbar injection of 0. 2 mL of 20% galaetose once per day. Lipo-antisense oligodeoxynucleotide（ Lipo-ASODN,0. 2 mL） was retrobulbarly injected 4 hours after the injection of galactose at one-day intervals. The animals were sacrificed and lenses were obtained to evaluate the apoptosis of LECs and the effect of c-myc ASODN on LECs apoptosis induced by galactose was examined by TUNEL assay after 7, 14 and 24 days. The ultrastructural changes of LECs were examined under the transmission electron microscopy（ TEM）. Results A significant difference in the apoptotic rate of LECs was found among the 7 day,14 day and 24 day groups（F7 days =3 418. 495, P 〈0. 01 ;F14 days = 1 137. 555,P 〈 0.01;F24 days= 2 198. 871,P 〈 0.01 ）. The apoptotie rate of LECs in the galactose group was markedly higher than that in the normal saline solution group 7 days, 14 days and 24 days after the experiment（ P 〈 0.01 ）. The apoptotie rate of LECs in the galaetose ＋ lipo ＋ ASODN group significantly declined in comparison to the galaetose group after 7 days, 14 days and 24 days （ P 〈 0.05 ）. TUNEL assay showed the condensation, breakage and irregularity of the nuclei of apoptotic cells in the galactose group. The destruction of the ultrastructure of the cells and organelles were observed under the transmission electron microscope. Conclusion Gatactose induces apoptosis of LECs in cataractogenesis. C-myc ASODN inhibits apoptosis of LECs induced by galactose.