Effects of Bu-Shen-Ning-Xin Decoction on immune cells of the spleen and bone marrow in ovariectomized mice.

Osteoimmunology is a new discipline that focuses on the interaction between the bones and the immune system. Immune cells play an important role in bone metabolism. The aim of this study was to illustrate the effect of Bu-Shen-Ning-Xin Decoction (BSNXD) on lymphocytes in the spleen and bone marrow to explore the potential role on the bone. C57BL/6 mice were divided into four groups: sham, ovariectomized (OVX), OVX+BSNXD, and OVX+ estrogen. The sham and OVX groups were treated with saline, the OVX+BSNXD group was treated with BSNXD, and the OVX+ estrogen group was treated with estrogen. After mice were sacrificed, the spleens and bones were collected, and the lymphocytes in the spleen and bone marrow were analyzed. We found that BSNXD lessened the extent of the increase of CD4(+) and bone marrow. In contrast, these numbers were both increased in the OVX group. BSNXD had no influence on the percentage of γδ T cells. However, it increased the proportion of NK cells in the spleen and bone marrow. BSNXD lessened the extent of the increase of monocytes by ovariectomy. In vitro experiment, we found Tregs can decrease osteoclastogenesis when co-cultured with osteoclast precursor cells. This study suggests that BSNXD changes the immune environment and immune cells have a role in bone metabolism in OVX mice.