Increased mortality in female rats after severe diffuse traumatic brain injury is significantly attenuated by magnesium administration

Previous studies using focal models of traumatic brain injury have shown th at female animals have a higher postinjury mortality than male animals, and that this higher mortality may be due to a worsened magnesium homeostasis in the female animals. The present study examined whether a similar differe nce in male and female mortality existed following a more diffuse model of traumatic brain injury and whether any mortality could be attenuated by ova riectomy or posttraumatic magnesium administration. Severe impact-accelerat ion induced diffuse brain trauma resulted in a 20% mortality in male rats a s opposed to a 100% mortality in female animals (p< 0.05). This difference was not apparent at less severe injury levels. Administration of 750 mu mol es/kg magnesium sulphate intramuscularly at 30 min after severe trauma redu ced female mortality to 29% (p< 0.05). Female outcomes were similar in ovar iectomised animals suggesting that the protective effects of magnesium were unrelated to cyclic changes in gonadal hormones. We conclude that the high er mortality observed in female animals following brain trauma is dependent on injury severity and that this mortality can be significantly attenuated with posttraumatic administration of magnesium sulphate.