Effect of minocycline on the expression of glial cell-derived neurotrophic factor in retina of rats after optic nerve injury

Abstract

Objective To explore the neuroprotective mechanism of minocycline on retinal ganglion cells (RGC) by investigating the effect of minocycline on the expression of glial cell-derived neurotrophic factor (GDNF) in retina of rats after optic nerve injury.Methods Fifty-three SD rats were randomly divided into three groups:control group (3 rats),saline group (25 rats) and experimental group (25 rats).The left eyes in the saline and experimental group were made into the model of optic nerve injury.45 mg/kg minocycline or the same dose of normal saline was injected intraperitoneally in the rats of experimental group or saline group,respectively.The rats were euthanized at 1 d,3 d,7 d,14 d and 28 d postoperatively and the retina was collected.The morphological changes and the counting results of RGC were shown by hematoxylineosin staining.The concentration of active GDNF in retina was tested by semi-quantitative immunohistochemistry.Results The RGCs in the experimental group were more tidy with less degree of cytoplasmic vacuole formation than that in the saline group.The average number of RGC was higher in the experimental group than the saline group at all time points except 1 d.The differences were statistically significant (P ＜ 0.05).The concentrations of GDNF were higher in the experimental group than the saline group at all time points (P＜ 0.05).Conclusion Minocycline protects RGC through enhancing the expression of GDNF in the early stage after injury. Key words: Minocycline; Injury, nerve optic; Factor, neurotrophic, glial cell-derived