Impact of Prepubertal Social Subjugation and Anabolic Androgenic Steroid Exposure on Brain Morphology in Male Rats
Date
2007-08
Authors
Frahm, Krystle
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Abstract
Abused children have a higher propensity to abuse drugs, including anabolic
androgenic steroids (AAS). This research examined the impact of social subjugation (SS), as animal model of childhood abuse, and anabolic androgenic steroids (AAS), on the morphology of the anteroventral periventricular nucleus of the hypothalamus (AVPV) and the medial forebrain bundle (MFB) in pubertal Long-Evans male rats. This design was used to determine if the early experience of social subjugation or pubertal AAS exposure would alter the volume and areal cell density in the AVPV independently or in combination. The AVPV was selected because it is extremely sensitive to alterations by gonadal steroids and the MFB was selected as a control brain area. Four groups of rats received the following treatments: AAS, SS, AAS + SS, and vehicle control. On postnatal day 26 (P26) prepubertal gonadally intact male rats received subjugation, while controls remained in their cage undisturbed. SS consisted of daily exposures to an aggressive adult male conspecific for 10 minutes a day, 5 days a wk for 2 wks. At the onset of puberty (P40) half of the subjugated and non-subjugated male rats received the AAS testosterone propionate at a dose of 5mg/kg body weight. The AAS treatment continued for 5 days a week for 5 weeks. At the conclusion of testing, animals were sacrificed and perfused. Brains were sectioned at 60 µm and Niss1 stained. The volume and cross-sectional cell density was measured unilaterally in anatomically matched sections. All images were collected using an Olympus camera mounted on a microscope. The A VPV and MFB were analyzed with the NIH program Image J version 2.0. The volume in the A VPV was significantly reduced following SS, AAS, and AAS+SS compared to controls. There was no significant difference in MFB volume. There was also no significant difference observed for AVPV and MFB areal cell density. The results suggest that exposing the adolescent brain to either abusive early experiences or high levels of androgens, alone or in combination, can alter certain components of brain morphology. This animal model may provide insight into the impact of early experiences and AAS exposure on altered brain morphology in adolescence.
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Keywords
anabolic steroids, rats, brain, aggressiveness, morphology
Citation
Frahm, K. A. (2007). Impact of prepubertal social subjugation and anabolic androgenic steroid exposure on brain morphology in male rats (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.