RESUMO
Wnt signaling has been shown to inhibit adipogenic differentiation while inducing the osteogenic pathway of bone marrow stromal cells (BMSC). Patients with aplastic anemia (AA) often show excess fat accumulation in the bone marrow, possibly due to overactivation of the adipogenic pathway. Therefore, an activator of the Wnt signaling may alleviate the symptoms by enhancing the inhibition on the differentiation of BMSC towards adipocytes. To judge this hypothesis, the therapeutic effects of Wnt signaling activator lithium chloride (LiCl) combined with the currently used immunosuppressor cyclosporine A (CsA) on mice with AA in vivo was investigated. Mouse model with AA was established and the disease was confirmed by increased fat cell counts and decreased hematopoietic cell counts in the bone marrow of these animals. These mice treated with CsA 50 mg/(kg·d) alone or together with LiCl 20 mg/(kg·d), once daily for 5 d, then at day 14, 21 and 28 after establishment of mouse model with AA, the treatment effects were observed, including peripheral blood cells, bone marrow mononuclear cells (BMMNC) count and bone marrow biopsy examination in each group. The results showed that compared with the AA group, Hb content, WBC and BMMNC counts of CsA group and the combination group significantly increased. HE staining of bone marrow biopsy sample showed that the fat cells were significantly reduced in the bone marrow cavity (P < 0.05). Compared with the CsA group, Hb content, WBC and BMMNC counts of the combination group significantly increased (P < 0.05); HE staining of bone marrow biopsy sample showed that fat cells were reduced, the hematopoiesis of bone marrow was close to the normal. It is concluded that Wnt signal activator (LiCl) combined with CsA displayed a better treatment effect on AA in mouse models than the effect of using CsA only. They can promote the hematopoietic function of bone marrow, which may correlate with inhibiting differentiation of bone marrow mesenchymal stem cells into the fat cells by Wnt signaling.