The effects of epidermal growth factor, hyperbaric oxygen and tetanus toxin treatment on the amelioration of rats with spinal cord injury model

Spinal cord injury, is a major social problems in terms of its consequences, causes the loss of many functions of cord. The most effective treatment in spinal cord injuries is the prevention of secondary injury that commences with the crush The regeneration mechanisms and the prevention of apoptotic cell death are the most important aims of treatment in this injury. In this study, the effects of hyperbaric oxygen therapy (HBO), tetanus toxin (TT) and epidermal growth factor (EGF) on the prevention of apoptotic cascades and motor neuron protective effects of these treatments through their antioxidant mechanisms were evaluated. For the purpose of the comparison of three treatments, Sprague Dawley rats were divided into six groups (HBO, TT, EGF, Metilprednizolon as positive control, trauma and sham). Spinal cord injury was examined in all rats except for sham group, after the extradural compression was performed at T4-T10 vertebra by Yasargil aneurysm clip. TT and EGF treatment were applied just after the trauma, while HBO therapy was given in the first hour of trauma and it continued during 7 days. Functional evaluation of rats were assessed daily by using Basso-Beattie-Bresnahan (BBB) locomotor scale. Superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase enzymes activities were measured in the spinal cord samples of rats that were sacrified at the end of acute and subacute period which was the 8th day of trauma. The measurement of bax, bcl-2 and caspase-3 were conducted by western blot method in order to reveal apoptosis. The increase in the activities of SOD, GPx and scores of functional evaluation by HBO was significant (p<0.05). Besides, HBO led to upregulate the level of caspase-3 and bax; therefore it increased apoptosis through mitochondrial pathway (p<0.05). EGF caused significant increase in antioxidant enzyme levels (p<0.05), while it is not sufficiently effective with regard to apoptosis and functional evaluation compared to other treatment groups (p>0.05). TT also significantly increased both the level of enzyme activities and functional scores (p< 0.05). In contrast to HBO, TT significantly increased the level of bcl-2, but it decreased apoptotic proteins of bax and caspase-3 (p<0.05). As a conclusion, HBO treatment was found to be beneficial in the removal of reactive oxygen species and neurologic recovery. However, HBO-induced apoptosis mechanism needs to be revealed by future studies. Neuro-protective and healing effects of TT have been demonstrated by all evaluations and TT is expected to be an effective agent in the treatment of spinal cord injury.