The effect of early magnesium treatment after spinal cord trauma on secondary spinal cord edema in rabbits

Objective:To study the effect of postinjury treatment with Mg 2+ on spinal cord edema after traumatic spinal cord injury.Method:Forty rabbits were randomly assigned to five experimental groups on the basis of the administration of magnesium and the harvest time of spinal cord tissue specimens:Sham(Group A);Spinal cord injury(SCI) 24 hours(Group B);SCI with administration of Mg 2+ half an hour postinjury 24 hours(Group C);SCI 48 hours(Group D);SCI with administration of Mg 2+ half an hour postinjury 48 hours(Group E).The SCI animal models were made by using an improved Allen′s weight drop device.The content of H 2O、Mg 2+ 、Ca 2+ in the injured spinal cord tissue of each rabbit and the spinal cord histopathology were examined at 24 hours and 48 hours after spinal cord injury.Result:The H 2O content of injuried spinal cord tissue in each SCI group was significantly increased compared to the baseline level( P 0 01).The H 2O content in Group E was significant less than that in Group D ( P 0 05).The Ca 2+ content in each SCI group was significantly increased ( P 0 01) and Mg 2+ content was significantly decreased( P 0 05) in the injuried spinal cord tissue compared to the baseline level.Edema and hemorrhage in group C and E was less serious than those in group B and D.Conclusion:①These results suggest that the increase of tissue Ca 2+ content and the decrease of tissue Mg 2+ content in the injured spinal cord may relate to the secondary edema of spinal cord.②Early postinjury treatment with Mg 2+ can attenuate secondary spinal cord edema and hemorrhage. Author′s address Department of Orthopaedic,the Fisrt Affiliated Hospital of Sun Yat sen University of Medical Science,Guangzhou,Guangdong,510080