方法：用不同浓度噻吗心安处理体外培养的HCE细胞，在倒置显微镜下观察细胞的生长、增殖和形态变化，利用吖啶橙/溴化乙锭荧光双染色法检测质膜的通透性，利用琼脂糖凝胶电泳法检测DNA的断片化，利用透射电镜观察细胞的超微结构。

结果：噻吗心安在0.15625～5g/L的浓度范围内均能不同程度地引起HCE细胞出现不同程度的生长缓慢、数量减少、胞质皱缩、胞内空泡化、变圆脱落、质膜通透性增大、染色质凝缩、DNA断片化和出现凋亡小体等典型的细胞凋亡特征，并具有浓度和时间依赖性。临床使用浓度2.5～5g/L的噻吗心安对HCE细胞的凋亡诱导作用最大，处理28h的凋亡率高达83.23%～96.71%。

结论：噻吗心安在0.15625～5g/L的浓度范围内能显著诱导HCE细胞凋亡，临床使用浓度时对HCE细胞的毒性作用极大，在眼科临床中应谨慎使用。

METHODS: After in vitro cultured HCE cells treated with timolol maleate at different concentrations, the situation of cellular growth, proliferation, and morphology was checked under an inverted light microscope. And plasma membrane permeability, DNA fragmentations, and ultra-structure of HCE cells were detected by acridine orange/ethidium bromide(AO/EB)double fluorescent staining, DNA agarose gel electrophoresis, and transmission electron microscopy(TEM), respectively.

RESULTS: After treated with timolol maleate at concentrations from 0.15625g/L to 5g/L, in vitro cultured HCE cells showed typical characteristics of apoptosis, including growth retarding, number decreasing, cytoplasmic shrinking, vacuolation, falling off from well bottom of culture plate, plasma membrane permeability increasing, chromatin condensation, DNA fragmentation, appearance of apoptotic body, and so on. The apoptosis-inducing effect of timolol maleate was in dose- and time-dependent manners. The greatest apoptosis-inducing effect of timolol maleate on HCE cells was found at the clinic medication concentration of 2.5-5g/L, and their induced apoptotic rate of HCE cells at 28 hours reached 83.23%-96.71%, respectively.

CONCLUSION: Timolol maleate within the concentration of 0.15625-5g/L has an obvious apoptosis-inducing effect on HCE cells, and has tremendous toxicity to HCE cells at clinic medication dosage. Timolol maleate should be carefully utilized in ophthalmic clinic.