Alterations in thymopoiesis in intact and peripubertally orchidectomized adult rats of different age.
In adult rats 3, 6 and 9 months post-orchidectomy performed at the age of 30 days the thymus weight, thymocyte yield and relative proportions of thymocyte subsets (delineated by expression of CD4/CD8 molecules and TCRalphabeta) were analyzed in order to elucidate a putative role of male gonadal hormones in the shaping of thymus size and intrathymic T cell maturation. In 4-month-old control rats the thymus size and cellularity returned to the corresponding levels in 1-month-old rats. These levels were sustained during the following 6 months. In spite of that, the distribution of the main thymocyte subsets in these rats was subjected to significant changes, probably due to an age-associated diminishing thymus ability to provide efficient T cell differentiation. The results added further weight to a potential feedback regulatory role of CD4+8- cells in thymopoiesis. Furthermore, they revealed that the orchidectomy-induced (i) enlargement of the thymus size and enrichment of the thymic lymphoid cell content are of a limited duration; and (ii) alterations in the relative proportion of thymocytes become quantitatively more pronounced with duration of the gonadal deprivation. Thus, the study also indicates that the age-associated changes in gonadal hormones may be, at least partly, responsible for the age-related reshaping of the T cell maturation sequence, and hence for remodeling T cell dependent immune functions.
Leposavic
Gordana
G
Institute for Immunology and Virusology Torlak, 458 Vojvode Stepe, 11221, Belgrade, Yugoslavia. leposa@afrodita.rcub.bg.ac.yu
Pejcić-Karapetrović
Branka
B
Kosec
Dusko
D
D000375:Aging / Q000502:physiology*; D000818:Animals; D015704:CD4 Antigens / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D002455:Cell Division; D006411:Hematopoiesis, Extramedullary / Q000502:physiology*; D008297:Male; D009919:Orchiectomy; D009929:Organ Size; D051381:Rats; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis; D013950:Thymus Gland / Q000166:cytology* / Q000502:physiology
D015704:CD4 Antigens; D016827:CD8 Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta