The Effect of Antimetabolites for Inhibiting the Proliferation of Rabbit Lens Epithelial Cells in Vitro

The most common cause of blurred vision after extracapsular cataract extraction is known to be an opacification of the posterior lens capsule. The pathogenesis of posterior lens capsule opacification is primarily caused by residual lens epithelial cells. For the prevention of posterior capsular opacification, several kinds of anti-mitotic drugs is being actively investigated. But the antimitotic drugs are not clinically used due to toxicity towards the intraocular tissues. The objectives of this study is to evaluate the effect of mitomycin C and tirilazad mesylate(FREEDOX(TM)) respectively for inhibiting the proliferation of rabbit lens epithelial cells when it is administered in a short period. Lens epithelial cells from white rabbits were harvested andcultured for 4 passages. Mitomycin C was applied for 3 minutes with 0.025mg/ml and 0.05mg/ml in concentration respectively. The proliferation assay was performed by [(3)H]-thymidine uptake test. Significant decrease of lens epithelial cell proliferation appeared in both drugs.When Mitomycin-C was applied with 0.025mg/ml for 3 minutes, cell proliferation was reduced to 31.5% compared with control and in 0.05mg/ml concentration, to 12.5%. When tirilazad mesylate was applied 0.15mg/ml for 3 minutes, cell proliferation was reduced to 46.5% compared with control and in 1.5mg/ml concentration, to 7.5%. If futher investigation would show the effectives and safety of these drugs, these agents could be applied into the lens capsular bad at the time of surgery to prevent the posterior capsular opacification after cataract surgery.

Lipocortin 1 mediates the suppressive effects of dexamethasone on CoNinduced proliferative response and nitric oxide production in rat splenic leukocytes

Lipocortin 1 has been proposed as a putative mediator of anti-inflammatory actions of glucocorticoids. We investigated the role of lipocortin 1 in the effect of dexamethasone using rat splenic leukocytes. Concanavalin A(ConA; 1-microgram/ml) increased the leukocyte proliferation and nitric oxide(NO) generation, which were measured as (3H)-thymidine uptake by the cells and nitrite accumulation in the culture media, respectively. Dexamethasone suppressed CoNinduced cell proliferation, in a concentration-dependent manner with EC-50 around 50nM. The addition of anti-lipocortin 1 (Anti-LC1) reversed dexamethasone effects: 0.24, 1.2, 6 microgram/ml of Anti-LC1 reversed dexamethasone(50nM)-induced suppression of thymidine uptake by 9+/-3%, 16+/-3%, 36+/-5%, respectively; 0.24, 1.2, and 6-microgram/ml of Anti-LC1 reversed dexamethasone-induced decrease of nitrite concentration by 49 +/- 16%, 61 +/- 20%, 77 +/- 19 %, respectively. The present data indicate that lipocortin 1 mediates, at least in part, glucocorticoids-induced suppression of leukocyte proliferation and blockade of NO generation.

~3H-THYMIDINE UPTAKE ASSAY OF FRTL5 CELLSI THE INFLUENCE OF CELL FACTORS / 西安交通大学学报(医学版)

The amount of ~3H-TdR incorporation into D?A of FRTL5 cells was expressed as CPM/?gD?A. THe responsibity of FRTL5 cells to stimulators such as TSH was expressed as % against thJ control CPM/?gDNA of the experimental group divided by that of the control. The responsibilities of FRTL5 cells which were recovered after being fr-o zen under-180℃ for a long time, to TSH 200?g/ml were 2741% and 3028% respectively, and the responsibilities of cells cultured in TSH media continuously for a long time, to TSH 200?u/ml and 2000?u/ml were 736% and 719% respectively. There was statistically significant differences between the two groups of the cells mentioned above. This showed that freezing FRTL5 Cells for a long time Such as 2 months was able to recover the decreased responsibility of the Cells due to a long continuous TSH culture.