Abstract: Objective To examine the protective effects of 17-β estradiol on the experimental model of spinal cord injury (SCI) rats. Methods One hundred and eighty male Sprague Dawley (SD) rats, after Allen’s model, SD rats were divided into three groups: the sham group, the acute spinal cord injury (control groups) and the acute spinal cord injury supplying with 17-β estradiol treatment group. SCI was made by Allen’s weight dropping, impacting on the posteriors of spinal cord T10.The content of malonyldialdehyed (MDA), glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined by chromatometry. The expressions of Caspase-3 and Bcl-2 family in the injured spinal cord were detected by immunohistochemical staining. Results The BBB scores at each time point in 17-β estradiol treatment group were significantly higher than that in SCI group (EM>P/EM><0.05). The contents of GSH, SOD, GSH-Px and the expression of Bcl-2 protein at the majority of time point in 17-β estradiol treatment group were significantly higher than that in SCI group(EM>P/EM><0.05), however, the MDA, Caspase-3 and Bax were markedly decreased (EM>P/EM><0.05). Conclusions This study suggests that 17-β estradiol administration

Key words: 17-β estradiol, Spinal cord injury, Thiol antioxidant, Apoptotic protein, Chromatometry, Immunohistochemistry, Rat