Effects of the duration of progesterone treatment on the resolution of cerebral edema induced by cortical contusions in rats.
PURPOSE. The aim of the present study was to assess the effect of different durations of administration of progesterone (4 mg/kg) on the resolution of edema 6 days after medial frontal cortex contusions (MFC) in male adult rats.


METHODS
Animals sustaining injury were injected with progesterone or its vehicle for 3 days or for 5 days beginning the first hour after surgery. On the 6th day the rats were killed and their brain water content was measured.


RESULTS
We confirmed the presence of edema six days after MFC. However, both 3 and 5 days of treatment with progesterone significantly reduced edema in the injured brains but the five days of treatment were more effective. The effects of progesterone depend upon the duration of the treatment because there are two waves of edema. The first phase begins within a few hours of the injury and the second starts several days later.


CONCLUSIONS
Our data are consistent with earlier findings showing that longer durations of progesterone administration lead to more complete behavioral recovery as well as to an increased number of surviving neurons.
Galani
R
R
Brain Research Laboratory, Department of Psychology and Department of Emergency Medicine, Emory University, Atlanta, Georgia 30322, USA.
Hoffman
S W
SW
Stein
D G
DG
D000208:Acute Disease; D000818:Animals; D001929:Brain Edema / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D001930:Brain Injuries / Q000150:complications*; D005625:Frontal Lobe / Q000293:injuries*; D008297:Male; D009929:Organ Size; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014867:Water / Q000032:analysis
D014867:Water; D011374:Progesterone