Effect of Nitric Oxide on the Proliferation of Cultured Human Tenon Capsule Fibroblasts Exposed to Benzalkonium Chloride

PURPOSE: To investigate whether the effect of benzalkonium chloride (BAK) on the proliferation of human Tenon capsule fibroblasts (HTCF) is mediated by nitric oxide (NO) in tissue culture . METHODS: HTCF were exposed to various concentrations of BAK for 24 hr and the cellular proliferation and production of NO were assessed by MTT and Griess assays, respectively. A non-specific nitric oxide synthase inhibitor, 0, 5 mM N(omega)-Nitro-L-arginine methyl ester (L-NAME), or NO donor, 100 micro M sodium nitroprusside (SNP), was co-administered with BAK to assess the effect of NO on the proliferation of cells. RESULTS: BAK decreased cellular proliferation in a dose-dependent manner and this effect was accompanied with decreased nitrite production. The cellular proliferation was increased significantly with BAK/SNP co-administration but decreased with BAK/L-NAME co-administration. CONCLUSIONS: NO donor increased the proliferation of HTCF which was decreased by BAK. The effect of BAK on the proliferation of HTCF may be possibly mediated by NO.

Effect of Mitomycin C on the Proliferation and Nitric Oxide Production in the Cultured Trabecular Meshwork Cells

PURPOSE: To investigate the effect of mitomycin C on the proliferation of cultured trabecular cells and its relation to nitric oxide (NO) production. METHODS: The effect of NO donor, SIN-1, on the proliferation of primarily cultured porcine trabecular meshwork cells was studied with MTT assay. After treatment with mitomycin C at various concentrations for 1 hour, the proliferation was assessed by MTT assay and the production of nitrite was assessed by Griess reaction after 24 hours and 3 days respectively. RESULTS: SIN-1 significantly inhibited proliferation of cultured trabecular meshwork cells (p0.05). CONCLUSIONS: Both NO donor and mitomycin C have an inhibitory effect on the proliferation of trabecular meshwork cells. However, inhibitory effect of mitomycin C was not related to the production of NO.

Effect of Cholinergics on the Survival and Production of Nitric Oxide in Cultured Ciliary Muscle Cells

PURPOSE: To investigate the effect of cholinergics on the survival and production of nitric oxide (NO) in the cultured ciliary muscle cells. METHODS: Primarily cultured porcine ciliary muscle cells were exposed to the pilocarpine and to the atropine at various concentrations for 24 hours. The cellular survival was assessed by rapid colormetric assay (MTT assay) and the production of nitrite was measured by Griess reaction. NO production was measured after co-administration of pilocarpine and atropine. RESULTS: Cultured ciliary muscle cells expressed alpha-smooth muscle actin. Both pilocarpine and atropine did not affect the cellular survival (p>0.05). Pilocarpine decreased the production of NO significantly from 10 micro M (p<0.05). Atropine increased NO production from 1 micro M and inhibited pilocarpine-induced inhibition of NO production. CONCLUSIONS: Pilocarpine decreases the production of NO that abolished by atropine in the ciliary muscle cells. Pilocarpine may constrict the ciliary muscle by inhibiting production of NO and decrease uveoscleral outflow subsequently.