Experimental study of protective effect of magnesium sulfate on secondary spinal cord injury

Objective: To investigate the possible mechanism of protective effects of magnesium sulfate on theinjuried spinal cord in rabbit model.Method: Thirty- six Newzealand white rabbits were randomly assigned intothree groups: Sham (Group A); Spinal cord injury (SCI) (Group B); SCI with magnesium sulfate treatment(Group C).The SCI animal model was made by using an improved Allen′s weight- drop device.After thirtyminutes the animals of group B were injected with 600mg/kg distilled water through intraperitoneum and groupC were injected with 600mg/kg magnesium sulfate.The contents of H2O, Mg2+, Ca2+ in the injuried spinal cordtissues were examined.The histopathology and ultrastructure of injuried spinal cord tissues were observedthrough light and electron microscopes.The apoptosis cells were assayed through TUNEL(TdT mediated dUTP-biotin nick end labeling).The positive cells were quantitated by a computer image analysis system.Result: Thecontents of H2O and Ca2+ in injuried spinal cord tissues in each SCI group were significantly increasedcompared to those in the Sham (P0.01), and those in group C was less than those in group B (P0.05).Thecontents of Mg2+ significantly decreased(P0.01) in the injuried spinal cord tissues.The damage of structure ingroup C was less serious than that in group B.The number of apoptosis cell in group B was more than thatin group C(P0.01).Conclussion: Earlly intervention with magnesium sulfate can decrease the secondary spinalcord injury.