Progesterone decreases cortical and sub-cortical edema in young and aged ovariectomized rats with brain injury

Traumatic brain injury (TBI) -induced brain edema can be reduced by acute progesterone (PROG) treatment in young adult males and females, and in aged males. To extend these findings we tested these hypotheses: 1. Acute PROG treatment post-TBI will reduce cortical edema in aged females as much as in young adults. 2. TBI will induce edema in sub-cortical structures (SCS): the thalamus (TH), hypothalamus (HT), brain stem (BS) and anterior pituitary (AP). 3. Acute, systemic PROG treatment post-TBI will reduce edema in SCS.

Young adult (n = 42) and aged (n = 40), bilaterally ovariectomized rats were given medial frontal cortical (MFC) contusion injury, treated with PROG (16 mg/kg body weight) or vehicle at 1, 6 and 24 hours post-injury and killed at 6, 24 and 48 hours post-injury. Their brains were removed and the target areas isolated and measured for water content.

TBI induced cortical and delayed sub-cortical edema. Acute PROG treatment decreased this edema. At 6 hours post-TBI serum PROG levels were substantially elevated in both young and aged, PROG-treated, groups, but were higher in the latter.

Acute PROG treatment post-TBI could prove an effective intervention to prevent or attenuate systemic, post-injury cortical and sub-cortical edema in young and aged females.