Low-dose chloroquine mediated neuroprotection against n-methyl-d-aspartate induced excitotoxicity in adult mice / 中华眼底病杂志

ABSTRACT

Objective:To investigate the protective effects of different concentrations of chloroquine on RGC in n-methyl-d-aspartate (NMDA) injured mice and its possible mechanisms.Methods:Fifty-four healthy male C57/BL6 mice were randomly divided into three groups, 18 in each group. The mice in low-dose chloroquine group were intraperitoneally injected with chloroquine solution at a dose of 10 mg/kg daily. Mice in high-dose chloroquine group were intraperitoneally injected with chloroquine solution at a dose of 100 mg/kg, and the mice in control group were intraperitoneally injected with the same volume of PBS. NMDA intravitreal injection was performed 2 days after intraperitoneal injection, 5 nmoles NMDA was injected into the left eye, and the same volume of PBS was injected into the right eye as a control. The RGC staining of retinal plaques were performed 7 days after NMDA injection, and the number of alive RGC was calculated. The visual acuity and electroretinogram were used to evaluate the electrophysiological functions of RGC at 9 and 10 days after modeling. Real-time quantitative PCR and retinal frozen sections and glial fibrillary acidic protein (GFAP) immunofluorescence staining were performed 11 days after NMDA injection to evaluate the glial activation of the retina. The density, visual acuity, and the amplitude of PhNR-wave of RGC between groups were compared by one-way analysis of variance.Results:At 7 days after NMDA injection, the density of RGC in retinal patch of low-dose chloroquine group was significantly higher than that of intraperitoneal injection of PBS control group ( F=54.41, P<0.01). The density of RGC in retinal patch of high-dose chloroquine group was lower than that of control group ( F=1.18, P>0.05). The visual acuity was higher than control group, and the difference was statistically significant ( F=9.10, P<0.05). The amplitude of PhNR-wave was significantly higher in low-dose chloroquine group than that of the control group ( F=17.60, P<0.01). The mRNA level of inflammatory factor and GFAP positive signal was also significantly lower than that of the control group ( F=23.66, P<0.05). The amplitude of PhNR-wave, the expression of GFAP ( F=110.20, P<0.01) and the mRNA level of inflammatory factors ( F=167.60, 17.78; P<0.01) in the high-dose chloroquine group were higher than the other two groups, and the differences were statistically significant. Conclusions:In NMDA injury retinal model, low-dose chloroquine significantly increased the survival and physiological function of RGC, and the mechanism may be related to the inhibition of glial activation and inflammatory response. High-dose of chloroquine would aggravate the apoptosis of RGC.