RESUMO
ObjectiveTo study the effect of Bazi Bushen capsules on delaying the aging process of naturally aging mice and its mechanism. MethodThe mice were randomly divided into four groups according to their body weight， namely， aging group， low-dose Bazi Bushen capsules group （1 g·kg-1）， high-dose Bazi Bushen capsules group （2 g·kg-1）， and rapamycin group （0.002 g·kg-1）. The debilitating signs were detected by behavioral tests and the weakness index was measured. The percentages of spleen T and B lymphocytes， effector T cells （TE）， memory T cells （TM）， naive T cells （TN）， helper T cells （Th）， cytotoxic T cells （Tc） ，Th1 cells， Th2 cells， and regulatory T cells （Treg） were determined by flow cytometry. Cell proliferation and the cell counting kit-8 （CCK-8） assay was used to detect the proliferation of lymphocytes in mice. The hematoxylin-eosin （HE） staining was used to observe the histopathological changes in the mouse spleen. The expression of cyclin-dependent kinase inhibitor 2A （p16） and cyclin-dependent kinase inhibitor 1A （p21） was detected by immunohistochemistry （IHC）. The mRNA expression of senescence-related proteins p16 and p21 was determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the inflammatory cytokines， including tumor necrosis factor-α （TNF-α）， interferon-γ （IFN-γ）， interleukin （IL）-1β， IL-2， IL-4， IL-10， and IL-12 p70， in peripheral blood of mice were detected by Luminex. ResultAs compared with the aging group， mice in the Bazi Bushen capsules and rapamycin groups showed significantly improved debilitating signs and reduced weakness index scores （P<0.05， P<0.01）， increased proportions of T cells， TN cells， Tc cells， Th2 cells， and Treg cells in the spleen， decreased proportions of TE cells， TM cells， Th cells， Th1 cells （P<0.05， P<0.01）， and increased proliferation of splenic lymphocytes （P<0.05， P<0.01）. In the Bazi Bushen capsules and rapamycin groups， clear structure of the red and white marrow marginal zone was observed in the spleen of mice， the area of the white marrow was increased， and the area of the red marrow was correspondingly decreased. The protein and mRNA expression of aging-related proteins p16 and p21 in the spleen was decreased （P<0.01）， the levels of serum pro-inflammatory cytokines IL-1β， IL-2， IL-12 p70， IFN-γ， and TNF-α levels were decreased， and the levels of IL-4 and IL-10 were increased （P<0.05， P<0.01） in the Bazi Bushen capsules and rapamycin groups as compared with the aging group. ConclusionBazi Bushen capsules have the effect of regulating the debilitating signs of natural aging mice， regulating the immune homeostasis and inflammation level of the body， and reducing cell aging.