Effect of high dosage of methylprednisolone on rat retinal ganglion cell apoptosis after optic nerve crush.

PURPOSE

To investigate the effect of high dose methylprednisolone (MP) on retinal ganglion cells (RGC) apoptosis.

METHODS

One hundred and twenty six Wistar rats were divided into normal control, crush control and MP treatment groups. High dose MP and 0.9% sodium chloride were injected intravenously at 1 h after injury in the treatment group and crush control group, respectively. Apoptotic cells, Bcl-2 and Bax positive cells were located and calculated by terminal-deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL), immunohistochemical method and retinal whole-mount combined with section technique at day 4, 7, 14 after crush, respectively.

RESULTS

The TUNEL-labeling cells, Bcl-2 and Bax positive cells were detected in the ganglion cell layer of retina. Few apoptotic cells, a few of Bcl-2 and Bax positive cells were observed in normal control groups. The numbers of positive cells increased gradually after crush. The number of apoptotic cells and Bax positive tells in treatment groups was less than that in crush group significantly (P < 0.05), while the number of Bcl-2 positive cells in treatment group was more than that in crush group at day 4, 7 and 14 after crush significantly (P < 0.05).

CONCLUSIONS

These results suggest that high dose MP can inhibit the apoptosis of RGC after optic nerve crush probably through up-regulation of Bcl-2 expression and down-regulation of Bax expression.