[Dexamethasone inhibits trabecular meshwork cell growth and epidermal growth factor mRNA expression in vitro]

To investigate the effect of dexamethasone on cultured trabecular meshwork cell growth and the cell expression of epidermal growth factor (EGF) mRNA in vitro.

Human trabecular meshwork cells were cultured in vitro. The third passage cells were used in this experiment; with the addition of 300 microgram/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 alpha-(32)P 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.

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 microgram in the test group, while 22.5 microgram in the control group. In both groups, 14 microgram 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.

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.