Effect Of MiR-125a-5p On Histopathology Of Experimental Optic Neuritis

Objective To study the effect of overexpression or inhibition of miR-125a-5p in vivo on the weight,clinical score,optic nerve and retinal pathology of experimental optic neuritis,and to explore the effect of miR-125a-5p on optic neuropathology in EAE mice and its role in optic neuritis.Methods The mice were randomly divided into 6 groups: normal group,EAE group,125 a group,125a-CON group,125a-RNAi group and 125a-RNAi-CON group.Except for the normal group and the EAE group,the remaining 4 groups were injected with the corresponding adeno-associated virus 2 weeks before immunization.On the day of immunization,we established EAE models induced by MOG35-55 in experimental groups except the normal group.Weight and clinical score were recorded daily.On day 19 after immunization,we extracted the optic nerve to verify the successful transfection of viruses that overexpress or inhibit miR-125a-5p.At the same time,HE stained slices of the optic nerve and eyeball were made to evaluate the infiltration of inflammatory cells in the optic nerve and retina.Luxol fast blue stained slices of the optic nerve were made to evaluate nerve demyelination.Results The results of real-time PCR showed that the overexpression of miR-125a-5p adeno-associated virus was successfully transfected in vivo,and the miR-125a-5p adeno-associated virus transfection effect was not satisfactory.Weights of mice in the normal group showed a normal growth trend,and weights of mice in experimental groups decreased during the onset of the disease,and then returned to the normal growth trend.The 125 a group had the smallest weight loss.The mice in experimental groups got sick on day 10 to 11 after immunization.Clinical score reached the highest value within a few days after onset,and gradually decreased after being maintained for a few days.The average onset time of group 125 a was the latest,and the peak of the average score appeared the latest.In HE staining,optic nerves of the normal group showed a linear formation of nuclei in a bead-like manner and had a moderate cell density.The structure of each layer of the retina is clear.In each experimental group,there was infiltration of inflammatory cells in the optic nerve and optic nerve sheath,the density of cells in the optic nerve was large.The arrangement of cells in the inner and outer nuclear layers of the retina is disordered.According to the inflammatory cell infiltration score,the cell infiltration score in the 125 a group was significantly lower than that in the EAE group(P <0.05)and 125a-CON group(P <0.01).miR-125a-5p can significantly reduce the infiltration of inflammatory cells into the optic nerve.In LFB staining,the optic nerve of the normal group was stained uniform blue,and the nerve fibers were arranged compactly and orderly.In experimental groups,the optic nerve fibers were arranged in disorder,and demyelination occurred.The demyelination degree of 125 a group was lower than that of the EAE group and the 125a-CON group.Conclusion Overexpression of miR-125a-5p can reduce the clinical severity of EAE mice,reduce inflammation cell infiltration in the optic nerve,and prevent demyelination of the optic nerve.