The Experimental Study On Estrogen Therapy Of Spinal Cord Injury

Objective:To observe the effects of estrogen on hindlimb movements recovery and the formation changes of neural cells of spinal cord injury in rats. To study the expression and the changes of GAP-43 in spinal cord of the animals. To preliminary study on the mechanism estrogen promotes maintenance of function in neurons after SCI.Methods:144 eight-week male Sprague Dawley rats that from the same batch but different brood were randomly divided into four groups, including the normal control group (group A), sham operation group (group B), normal saline solution group(group C) and estrogen group (group D). The groups A were not treated;The acantha and total vertebral lamina of T13～L5 of the rats in group B were cut off and the Spinal cord were uncovered; Spinal cord injury models of the animals in group C and D were established with Allen's bump equipment.The two groups (groupC and D) were given respectively estrogen 4 mg/kg body weight or equal volume of physiological saline at 30 minutes,1st day,2nd days after the operation. The Recovery of Neural Function of injured spinal cord was evaluated by The Basson Beattle Bresnahan rating scale and Rivlin platform test at 3rd days,1st week,2nd weeks,3rd weeks and 4th weeks after operation in respective group of experiment. The animals were sacrificed and Ti3～L5 spinal cord were achieved at 1st days,3rd days,1st week.2nd weeks.3rd weeks and 4th weeks after SCI. Pathological changes were observed by hematoxylin-eosin staining and GAP-43 positive cells was measured with immune-histochemical staining of SABC method.Results:①To assess the neurological function of spinal cord:The BBB score and Rivlin plateform test was no difference between group A and group B but were significant difference between group C and group D (P<0.01)at 1st week,2nd weeks,3rd weeks and 4th weeks after SCI, group D was superior to group C ②The results of hematoxylin-eosin staining:The structure, nissl bodies and membrane of neuron cell of the rats in group A and group B is normal. Degeneration, necrosis and a decrease in the number of neuron were much serious in group C than those in group D at various time points.③The result of immunohistochemical staining:The numbers of GAP-43 positive neurons in spinal cord of these animals of the group A and B had weak expression. GAP-43 Positive Expressions were detected at the first day after the operation and the amounts of GAP-43 Positive Expressions is the most at 7th day after SCI and then started to drop off and were significantly lower in group C than those in group D.Group D have more the number of GAP-43 positive cells and the cells were more hyperchromatic than that of group C at different time points and there was significant difference between them (P<0.05).Conclusion:Exogenous estrogen can promote the recovery of neural function, hindlimb movements recovery and GAP-43 positive expressions of neurons in rats after SCI;It can alleviate degeneration, necrosis of neuronal cells after SCI.