地塞米松体外抑制人眼小梁细胞生长及表皮生长因子mRNA的表达

摘要

Objective To investigate the effect of dexamethasone on culturedtrabecular meshwork cell growth and the cell expression of epidermal growth factor (EGF) mRNA in vitro. Methods Human trabecular meshwork cells were cultured in vitro. The third passage cells were used in this experiment; with the addition of 300 μg/ml dexamethasone in the culture medium in the test group, the culture was carried out as routine. After 5 days, the cell growth conditions were observed. After 7 days, the cells in the test and the control group were collected, and mRNA was drawn from them in both groups. EGFcDNA probe with α-32P isotope labeling was used to proceed dot blot hybridization and autoradiography to detect EGFmRNA of the cells. A computerized laser instrument was used to scan the size of dot blot hybridization, the relative value of the optical density was measured in the autoradiographs, and the inter-group comparison was made. Results Trabecular meshwork cells were inhibited by dexamethasone in the test group. The cells in the control group had been confluent at the 5th day, but the cells in the test group still grew like tribes. The total RNA was 14 μg in the test group, while 22.5 μg in the control group. In both groups, 14 μg RNA was used for dot blot hybridization test with EGFcDNA probe. Autoradiographic image was positive in the two groups. The results of the scanning and the measurement of the autoradiograph density showed that dexamethasone obviously decreased the EGFmRNA expression of trabecular meshwork cells. Conclusions Dexamethasone can inhibit trabecular meshwork cell growth in vitro. At first it affects the cell total RNA transcription and the second affects the EGFmRMA expression. It is suggested that steroid glaucoma be caused by the inhibition of various physiological and metabolic functions of trabecular meshwork cells induced by dexamethasone.%目的 探讨地塞米松对培养的人眼小梁细胞生长的影响及抑制小梁细胞表达表皮生长因子(epidermalgrowthfactorEGF)mRNA的情况。方法 取人眼小梁组织进行小梁细胞体外培养，对传3代的小梁细胞进行地塞米松处理实验。实验组在传代后的培养液中按300μg/ml加入地塞米松，另一组作为对照组进行常规培养，观察生长5d后的细胞情况，取培养7d的两组小梁细胞分别提取RNA,用EGFcDNA探针，α-32P同位素标记进行斑点杂交，放射自显影。对显影片用计算机激光密度扫描，测定吸光度A值相对值进行组间比较。结果 加入地塞米松300μg/ml实验组，小梁细胞生长明显受到抑制，5d时对照组细胞已经融合，地塞米松组的细胞仍呈集落状态。从对照组小梁细胞提取RNA22.5μg，地塞米松组提取RNA14μg，取14μg两组等量RNA，用EGFcDNA探针进行斑点杂交，结果阳性。激光密度扫描值地塞米松组明显低于对照组。结论 地塞米松对培养的人眼小梁细胞有明显的生长抑制作用，通过抑制总RNA转录及EGFmRNA表达而抑制小梁细胞生长。提示糖皮质激素性青光眼是因抑制了小梁细胞的多种代谢和生理功能所致。