[ effect of sex steroid hormones on brain edema and intracranial pressure after experimental traumatic brain injury in rats]

ABSTRACT

We investigated the role of sex hormones on changes in brain edema intracranial pressure [ICP], cerebral perfusion pressure [CCP] after trauma brain injury [TBI] in ovarectomized female [OVX] rats. In this study female rats are divided into five groups. Control group [Intact] sham group and other groups include vehicle, estrogen group [1mg/kg] and progesterone group [8 mg/kg] which on all groups TBI was induced by Marmarou method. 30 minutes after TBI, drugs were injected i.p. ICP was measured in spinal cord using a standard procedure. CPP was calculated by the mean arterial pressure [MAP] - ICP. Neurologic scores were measured by motor, eye and respiratory reflex. The results showed after TBI, water content was significantly lower in estrogen and progesterone groups [P<0.001] compared with vehicle group. Analysis showed a stable ICP up to 24 hours. The ICP in estrogen and progesterone groups was significantly decreased at 4 and 24 hours as compared to vehicle group [P<0.001in both cases]. The CPP at 24 hours after TBI, significantly increased in estrogen and progesterone groups compared with vehicle [P<0.001]. Also after TBI, neurologic scores was significantly higher in estrogen and progesterone groups as compared with vehicle [at 1 hours P<0.05, and at 24hours P<0.001 for estrogen], [at 1 hours P<0.01 for progesterone]. Our findings indicated an improvement of ICP, CPP and neurologic scores produced by pharmacologic doses of estrogen and progesterone after TBI in OVX rat. These effects may be contribute to neuroprotective effects of these hormones