title: Slow-release and injected progesterone treatments enhance acute recovery after traumatic brain injury.
abstract: The benefits of continuous progesterone release via subcutaneous silastic capsule implants were compared to daily subcutaneous injections in a rat model of traumatic brain injury (TBI). Adult male Sprague-Dawley rats received either bilateral frontal cortex contusions or sham surgery. Rats were injected with progesterone or vehicle at 1 and 6 h post-injury, then once every 24 h for six days with tapering of the dose over the final two treatments. Progesterone-packed silastic capsules were implanted post-injury while the animals were anesthetized. Behavioral assays for anxiety and locomotor activity were evaluated pre- and post-TBI. Brains were extracted eight days post-TBI and prepared for molecular assays. Decreased GABAA-4 levels complemented a decrease in anxiety behaviors on the Elevated Plus Maze for capsule compared to progesterone-injected animals prior to daily injections. All groups with implanted capsules increased locomotor activity compared to those given progesterone injections. In conclusion, steady-state progesterone treatment after TBI decreases edema and anxiety and increases activity, thus enhancing behavioral recovery. A continuous mode of pharmacological administration may prove to be more beneficial in translational and clinical testing than bolus injections over the same period of time.
authors.affiliation: Department of Emergency Medicine, Emory University, Atlanta, GA, USA. sarahmelissa@gmail.com
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Cutler
authors.forename: Jacob W
authors.initials: JW
authors.lastname: VanLandingham
authors.forename: Anne Z
authors.initials: AZ
authors.lastname: Murphy
authors.forename: Donald G
authors.initials: DG
authors.lastname: Stein
mesh_terms: D000818:Animals; D001007:Anxiety / Q000188:drug therapy; D017209:Apoptosis; D001522:Behavior, Animal / Q000187:drug effects; D001930:Brain Injuries / Q000188:drug therapy*; D004487:Edema / Q000188:drug therapy; D007249:Inflammation; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D011374:Progesterone / Q000008:administration & dosage* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000096:biosynthesis; D013997:Time Factors
chemical_list: C546262:Gabra4 protein, rat; D011963:Receptors, GABA-A; D011374:Progesterone