老年和青年SD大鼠外周血及免疫细胞分型测定分析

Differences in peripheral blood and immune cell phenotypes between aged and young Sprague-Dawley rats

目的比较老年SD大鼠和青年SD大鼠外周血和免疫细胞分型指标差异。方法12月龄和8周龄的SD大鼠进行外周血细胞计数、白细胞分类、免疫脏器系数、外周血免疫细胞分型、脾免疫细胞分型和脾T细胞P16表达量的检测。结果与青年大鼠相比,老年大鼠外周血白细胞计数,淋巴细胞百分比下降;红细胞,血红蛋白,中性粒细胞百分比,嗜酸性粒细胞百分比和嗜碱性粒细胞百分比升高;血小板和单核细胞百分比未见差异。胸腺系数、脾系数,老年大鼠与青年大鼠未见差异。外周血免疫细胞分型中,老年大鼠辅助T细胞、调节性T细胞、自然杀伤细胞和单核细胞比例升高,B细胞比例降低;脾淋巴细胞分型检测结果显示,老年组大鼠B细胞(CD45RA)低于青年组大鼠(P<0.01),两组CD3未见差异。老年雄性大鼠脾T细胞P16 mRNA表达量与青年雄性大鼠相比有明显升高(P<0.05)。结论老年大鼠外周血细胞及免疫细胞分型改变。脾T细胞P16表达可能作为免疫衰老的生物学标志。文中对检测结果进行了比较分析,将为研究老年疾病及衰老动物模型提供基础数据。

Objective Differences in peripheral blood and immune cell phenotype were compared between aged and young Sprague-Dawley rats.Methods The peripheral blood cell count,leukocyte classification,immune organ coefficient,immune cell phenotype in peripheral blood and spleen,and p16 expression in spleen T cells were detected in 8-week-and 12-month-old rats.Results Compared with young rats,the peripheral blood leukocyte count and percentage of lymphocytes in aged rats were decreased,and the percentages of erythrocytes,hemoglobin,neutrophils,eosinophils,and basophils were increased.However,there was no difference in the percentages of platelets and monocytes between groups.Additionally,there were no differences in thymus coefficient and spleen coefficient between young and old rats.Peripheral blood immunophenotyping indicated helper T cells,regulatory T cells,natural killer cells,and monocytes were increased,whereas B cells were decreased in aged rats compared with young rats.However,there was no significant difference in cytotoxic T cells.In old rats,markedly lower numbers of B cells(CD45RA)were present in the spleen compared with young rats,and there was no significant difference in CD3 cells between the groups.In addition,the expression of P16 mRNA in spleen T cells of aged male rats was significantly higher than in young male rats.Conclusions In aged rats,the differentiation of peripheral blood cells was deviated,the proportion of neutrophils was increased,and the proportion of lymphocytes was decreased compared with young rats.The proportion of regulatory T cells in the peripheral blood was increased,and the proportion of B lymphocytes was decreased in the peripheral blood and spleen in aged rats compared with young rats.These changes in innate immunity and acquired immunophenotype suggest that the immune function of aged rats was decreased and the regulation of immune function was disordered,similar to changes in the immune system of elderly population.The expression of P16 in spleen T cells was increased in aged rats,and therefore might be used as a biomarker for immune senescence.This study provides primary data for the study of age-related diseases and ageing animal models.