title: Interactive effects of cocaine and gender on thymocytes: a study of in vivo repeated cocaine exposure.
abstract: This study used a mouse model including both sexes to assess the impact of repeat cocaine exposure on the differentiation and function of T cell in thymus. Cocaine hydrochloride in 0.9% saline, 5 mg or 40 mg/kg, was administrated by i.p. injection to C57BL/6 mice for 10 days. Thymocytes were obtained 24 h after the 10th injection. Repeat in vivo cocaine exposure inhibited the proliferation of T lymphocytes in response to Con-A and Con-A plus anti-CD28. The proliferation induced by IL-2 in the Con-A stimulated T blasts was attenuated in cocaine treated mice. These effects were seen at a lower cocaine dose in female mice. The total number of thymocytes was reduced. Although the percentage of mature thymocytes (CD4+ CD8- and CD4- CD8+ cells) was not altered, the absolute cell numbers were attenuated. Both percentage and absolute cell number of immature thymocytes (CD4+ CD8+) decreased and the pre-mature (CD4- CD8-) cells increased. CD28 and CD25 expression were attenuated in Con-A stimulated thymocytes of mice treated with cocaine at 40 mg/kg. Interleukin 2 production was not significantly altered, however, gamma-IFN production was decreased by cocaine exposure at 40 mg/kg. In conclusion, cocaine exerts inhibitory effects on the function of mature thymocytes, and on the differentiation of thymocytes. A gender difference in response to cocaine was noted in that female mice were more sensitive to lower dose of cocaine exposure.
authors.affiliation: Maine Medical Center Research Institute, South Portland 04106, USA.
authors.forename: W
authors.initials: W
authors.lastname: Xu
authors.forename: T
authors.initials: T
authors.lastname: Flick
authors.forename: J
authors.initials: J
authors.lastname: Mitchell
authors.forename: C
authors.initials: C
authors.lastname: Knowles
authors.forename: K
authors.initials: K
authors.lastname: Ault
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D003042:Cocaine / Q000494:pharmacology*; D004334:Drug Administration Schedule; D005260:Female; D008213:Lymphocyte Activation / Q000187:drug effects; D018655:Lymphocyte Count / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012727:Sex Characteristics; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
chemical_list: D003042:Cocaine