Effect Of Glutathione On The Retina And Optic Nerve In Experimental Optic Neuritis

Objective: To explore the the protective effect of reduced glutathione(GSH) for demyelinating optic neuritis of the optic nerve and retina, SD rats in this experiment were set up experimental allergic encephalomyelitis (EAE) animal model. Using GSH intervention, we observe the morphological changes in rat optic nerve, retinal ganglion cells (RGCs) apoptosis and determinate malondialdehyde (MDA), glutathione peroxidase (GSH-PX), nitric oxide (NO) content in retinal tissue to explore the role of GSH in demyelinating optic neuritis .Methods: 54 female SD rats were randomly divided into normal group (n=6) and experimental group (n=48), The rats of experimental group were inculated intradermal injuction with the emulsion homogenate contained spinal cord of guinea pig and complete Freund's adjuvant (CFA) as the antigen in feet and subcutaneous injection of pertussis vaccine to the hind limbs at the same time. 48 EAE rats also randomly divided into control group (EAE group) of 18 rats and group of reduced glutathione (GSH group) of 30 rats. The rats in GSH groups were given intraperitoneal injection of GSH 100mg?kg-1?d-1 for 14d from the day of immunization, the rats in EAE group were given intraperitoneal injection of normal saline. Put to death in the early period, the peak period and recovery period, observed pathological changes in rat optic nerve, TUNEL assay apoptosis of RGCs, and determinated malondialdehyde (MDA), glutathione peroxidase (GSH-PX), nitric oxide (NO) content of retinal tissue.Results: 1.The incidence rate in EAE group was 100%, with symptom score of 1.5~4.5; the incidence rate in GSH group was 60%, with symptom score of 1~3. 2.In EAE group, the optic nerve fibers showed vacuolar degeneration with disorder, substantial infiltration of inflammatory cells under light microscopy, and showed diffuse demyelination under electron microscopy; in GSH group, the optic nerve fibers showed the relative rules under light microscopy, and relatively light demyelinating changes under electron microscopy. 3.There was almost no apoptotic cells in the retina in Normal group, but RGCs apoptosis were significant in EAE group.the differences of TUNEL-positive cells in early period, the peak period between EAE group and normal group were significantly statistical significance (P<0.01). RGCs apoptosis mitigated relatively in GSH Group, the differences of TUNEL-positive cells in early period, the peak period between GSH Group and EAE group were significantly statistical significance (P<0.01). 4.Compared with normal group, retinal MDA, NO content of the early period, the peak period increased and GSH-PX vitality reduced in EAE group, there was statistically significant difference (P<0.05); in GSH group, MDA, NO were of low content, GSH-PX was of high vitality comparing with EAE group, the difference had statistical significance (P <0.05).Conclusion: 1.Reduced glutathione can reduce the incidence of EAE rats and symptoms score; 2. Reduced glutathione can reduce pathological changes of the optic nerve;3. Reduced glutathione can inhibit apoptosis in rat RGCs, and reduce retinal MDA, NO content, improve GSH-PX vitality.