title: Tapered progesterone withdrawal promotes long-term recovery following brain trauma.
abstract: We previously demonstrated that after traumatic brain injury (TBI), acute progesterone withdrawal (AW) causes an increase in anxiety behaviors and cerebro-cellular inflammation compared to tapered progesterone withdrawal (TW). Our current study investigates the behavioral and cellular effects of AW two weeks after termination of treatments to determine the longer-term influence of withdrawal after injury. Adult, male Sprague-Dawley rats received either bilateral frontal cortex contusion (L) or sham (S) surgery. Rats were injected at 1 and 6 h post-injury, then every 24 h for six days. Vehicle (V)-treated rats were given 9 injections of 22.5% cyclodextrin, whereas AW rats received 9 injections of 16 mg/kg progesterone and TW rats received 7 injections of P at 16 mg/kg, followed by one at 8 mg/kg and one at 4 mg/kg. On day 8, sensory neglect and locomotor activity tests were initiated. Animals were killed 22 days post-TBI and the brains prepared for either molecular or histological analysis. Western blotting revealed increased brain-derived neurotrophic factor (BDNF) and heat shock protein 70 (HSP70) in TW vs. AW animals. P53 was increased in VL animals, whereas all progesterone-treated groups were equivalent to shams. TW animals had markedly decreased sensory neglect compared to AW animals and increased center time in locomotor activity assays. In addition, lesion reconstruction revealed a decreased lesion size for TWL over AWL over VL animals. Glial fibrillary acidic protein (GFAP) immunofluorescent staining followed this pattern as well. In conclusion, after TBI, AW affects select behaviors and molecular markers in the chronic recovery period.
authors.affiliation: Department of Emergency Medicine, Emory University, Atlanta, GA, USA. scutler@emory.edu
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Cutler
authors.forename: Jacob W
authors.initials: JW
authors.lastname: Vanlandingham
authors.forename: Donald G
authors.initials: DG
authors.lastname: Stein
mesh_terms: D000777:Anesthetics / Q000008:administration & dosage* / Q000009:adverse effects; D000818:Animals; D001522:Behavior, Animal; D015153:Blotting, Western / Q000379:methods; D001930:Brain Injuries / Q000188:drug therapy; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010456:Peptides, Cyclic; D010468:Perceptual Disorders / Q000209:etiology / Q000503:physiopathology; D011280:Pregnanolone / Q000008:administration & dosage* / Q000009:adverse effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects*; D013375:Substance Withdrawal Syndrome; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D034941:Upper Extremity / Q000503:physiopathology
chemical_list: D000777:Anesthetics; D019208:Brain-Derived Neurotrophic Factor; D005904:Glial Fibrillary Acidic Protein; D018840:HSP70 Heat-Shock Proteins; D010456:Peptides, Cyclic; D016159:Tumor Suppressor Protein p53; C087823:Z 008; D011280:Pregnanolone