Meeting Abstract
Injury to the homeotherm brain results in the upregulation of the estrogen-synthesizing enzyme aromatase. While peripheral estrogens have been shown to be neurogenic in birds and mammals, the possible effect of sex steroid hormones on the injured reptilian brain has not been examined. To determine whether or not injury-induced aromatization and or, local estrogen provision can affect neurogenesis following mechanical brain damage, adult male red-sided garter snakes (Thamnophis sirtalis parietalis) were castrated and implanted with either an empty silastic tube (control) or an individual or combination of tubes containing testosterone or estradiol. Fourteen days after implantation, animals were given a unilateral penetrating brain injury. All animals were then injected with the thymidine analog 5-Bromo-2’-deoxyuridine (BrdU) on the following schedule: immediately following surgery, 24 hours after surgery and 24 hours prior to perfusion. Animals were perfused 96 hours after lesions were administered, cryoprotected overnight, snap frozen on dry ice and sectioned on a cryostat in the coronal plane. Tissues were visualized using an antibody against BrdU. Sections containing the injury site and surrounding areas (III ventricle and preoptic area (POA) were examined for neurogenesis. The relative density of BrdU positive cells for each of the treatment groups was assessed and their locations recorded.
