(a) The effect of progesterone administration at 2 h after TBI on serum ratio of NGF/IL-6 in OVX rats (n = 7). ##P < 0.01, vs. Veh. (b) The effect of capsule form of progesterone on serum ratio of NGF/IL-6 in OVX rats (n = 7). +++P < 0.001, vs. Cveh. (c) Changes in percentage of serum ratio of NGF/IL-6 after TBI compared with vehicle in rats treated with progesterone (n = 7). & P < 0.05, vs. LP. Sh, sham; Veh, vehicle; LP, low progesterone; HP, high progesterone; CP, progesterone capsule; Cveh, capsule vehicle.