Potential prophylactic role of nitric oxide synthase inhibitors on experimentally induced cataract in rats

Nitric oxide [NO] has been related to numerous eye diseases such as cataract. In the present study, we investigated and compared the prophylactic role of selective and nonselective nitric oxide synthase [NOS] inhibitors on the development of selenite induced cataract in rats. The study comprised seven groups; of which four groups served as controls. Cataract was induced in three groups by a single subcutaneous injection of sodium selenite [4mg/kg] in 13-days old Lewis rats. One group was left untreated. The other two groups were treated with aminoguanidine or L-NAME [N G-nitro-L-arginine methyl ester] in a dose of 60mg/kg/day orally for nine days and treatment started two days before selenite injection. Slit lamp examination was done daily to detect lens opacity. Biochemical analysis of lenses was done seven days after selenite injection and included concentrations of nitrite, glutathione, calcium and soluble proteins, in addition to, Cellogel electrophoresis of soluble lens proteins. Ophthalmologic and biochemical results revealed a noticeable prophylactic role of both drugs on selenite cataract development after seven days of selenite injection. In addition, it was observed that aminoguanidine had a better protective role than L-NAME. It can be concluded that NO had an important role in the development of selenite induced cataract in rats since inhibitors of NOS could prevent the development of selenite cataract

Combination of a cyclooxygenase inhibitor and a nitric oxide synthase inhibitor in the treatment of experimental uveitis

Multiple factors and mediators interact to modulate the inflammatory process. In the present study, roles of nitric oxide [NO] and prostagl and in E[2] [PGE[2]] together with their simultaneous inhibition are investigated in a model of induced anterior uveitis in rabbits. Six groups of animals served as controls. Anterior uveitis was induced in 4 groups by intravitreal injection of 10 micro l complete Freund's adjuvant. One group was left untreated and the other three groups were treated three times daily for 14 days with N[G]-nitro-L-arginine methyl ester [L-NAME] 0.1% eye drops or with diclofenac 0.1% eye drops or with both drugs. Severity of uveitis was evaluated by clinical scoring at days 2, 7 and 14. On day 14, biochemical analysis of aqueous humor samples was performed for total proteins, albumin, nitrite and PGE[2]- Histopathological examination for iris and ciliary body was also done. Induction of uveitis caused elevation of clinical scores, elevation of the biochemically analyzed parameters and severe inflammatory signs by pathological examination. On day 14, both individual drugs and combination treatment produced significant decrease in intensity of uveitis compared to untreated animal model by all methods of evaluation. Combination treatment produced more reduction in clinical scores, more reduction in levels of total proteins, albumin and PGE[2] and also better histopathological picture compared to individual drug treatment. It can be concluded that both NO and PGE[2] are involved in the pathogenesis of Freund's adjuvant induced uveitis. Inhibition of production of both of them can improve the management of uveitis