Abstract
Age-related alterations in bone marrow cellularity were ex-amined on SD and Wistar SPF rats. Six rats / strain / sex were sacrificed at 58, 83, 109 and 123 or 135 weeks of age and quantitative assessment and categorization of the bone marrow cells were performed. One male and two female SD rats suffering from leukemia were excluded from statistics. Age-related increases of myeloblasts and plasma cells were observed in rats of either strain and either sex. Age-related decreases in percentages of lymphocytes were noticed in SD, but not in Wistar rats. Age-related alterations in absolute numbers of marrow lymphocytes were equivocal in either strain.
