Abstract: Objective To investigate the protective effect and its mechanism of Qizhen capsule on the retinal ganglion cell （RGCs） of the rat optic nerve crush model. Design Experimental study. Participants 72 healthy adult male SD rats. Methods The 72 rats were divided randomly into two groups: treatment group (36 rats) and control group (36 rats). All the right eyes were selected as the experimental eyes, using a micro optic nerve forceps with the clipping pressure of 40 g to crush the exposed optic nerve for 60 s at 2 mm from the optic disc. The left eyes served as normal controls. The rats were given drug by gastric perfusion 2 h after the crushing, and then once daily. The rats of treatment group were given 20% Qizhen solution with a dose of 2.5 ml/kg; control group rats were given saline with same does for consecutive four weeks. At the 28 days after injury, the rats were sacrificed, HE staining, the expression of Caspase-3 protein and Tunel were detected with 24 rats of each group. The rest 12 rats each group were used to detect the expression of Bax and Bcl-2. Main Outcome Measures The thickness of retina, the expression of Bax and Bcl-2. Results The average thickness of retina in Qizhen treatment group was (109.0±4.4) μm, and (101.8±7.6) μm in the control group（P=0.028）. The difference of the expression of Bax was significant （t=1.089，P=0.028）, but there was no significant difference of Bcl-2 (t=0.553，P=0.692) between the two groups. Conclusion Qizhen plays a protective role for RGCs in rat optic nerve crush model, decreasing the apoptosis of RGCs may through reducing the expression of Bax and Caspase-3.

Key words:  retinal ganglion cell, Qizhen capsule, nerve crush model, optic neuroprotection