Previous studies have shown that blood-ionized magnesium levels decline, associated with the development of histological changes(apoptosis), after traumatic brain injury. Therefore, we have a hypothesis that early magnesium salt treatment may be improving posttraumatic apoptotic change.

Thirty two anesthetized adult Sprague-Dawley rats were injured with a Marmarou's weight-drop device and bloodionized magnesium was checked, prior to and following magnesium administration(MgSO₄ 750µmol/kg. IM). The temporal pattern of apoptosis in rat brain after moderate diffuse axonal injury(mDAI) was characterized using TUNEL histochemistry.

After MgSO₄ injection at 30 min. posttrauma, animals demonstrated an elevated blood-ionized magnesium concentration reaching a maximum of 2.57±0.03mg/dL at 2.5 hours after drug administration and apoptotic index was significantly declined by about 45%(54.8±1.7, 51.5±3.2 at 12, 24 h in control group, 24.8±2.6, 20.5±1.4 at 12, 24 h in treated group, p<0.05).

These findings suggest that early treatment with MgSO₄ is very effective in histological findings following experimental traumatic brain injury in the rat. Clinically, we suspect that an increase in blood-ionized magnesium concentration with administration of magnesium salt may be associated with improvement in neurological and functional outcome.