Icariin accelerates bone regeneration by inducing osteogenesis-angiogenesis coupling in rats with type 1 diabetes mellitus.

BACKGROUND: Icariin (ICA), a natural flavonoid compound monomer, has multiple pharmacological activities. However, its effect on bone defect in the context of type 1 diabetes mellitus (T1DM) has not yet been examined. AIM: To explore the role and potential mechanism of ICA on bone defect in the context of T1DM. METHODS: The effects of ICA on osteogenesis and angiogenesis were evaluated by alkaline phosphatase staining, alizarin red S staining, quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence. Angiogenesis-related assays were conducted to investigate the relationship between osteogenesis and angiogenesis. A bone defect model was established in T1DM rats. The model rats were then treated with ICA or placebo and micron-scale computed tomography, histomorphometry, histology, and sequential fluorescent labeling were used to evaluate the effect of ICA on bone formation in the defect area. RESULTS: ICA promoted bone marrow mesenchymal stem cell (BMSC) proliferation and osteogenic differentiation. The ICA treated-BMSCs showed higher expression levels of osteogenesis-related markers (alkaline phosphatase and osteocalcin) and angiogenesis-related markers (vascular endothelial growth factor A and platelet endothelial cell adhesion molecule 1) compared to the untreated group. ICA was also found to induce osteogenesis-angiogenesis coupling of BMSCs. In the bone defect model T1DM rats, ICA facilitated bone formation and CD31hiEMCNhi type H-positive capillary formation. Lastly, ICA effectively accelerated the rate of bone formation in the defect area. CONCLUSION: ICA was able to accelerate bone regeneration in a T1DM rat model by inducing osteogenesis-angiogenesis coupling of BMSCs.

[Change of CD4(+) CD25(+) regulatory T cells and NK Cells in peripheral blood of children with acute leukemia and its possible significance in tumor immunity].

This study was purposed to investigate the changes of CD4(+) CD25(+) regulatory T cells and NK cells in peripheral blood of acute leukemia children at different stages, the function of immune system and the possible roles of the CD4(+) CD25(+) regulatory T cells as well as NK cells in leukemia immunity. The number and proportion of CD4(+) CD25(+) regulatory T cells and NK cells were detected by flow cytometry in the peripheral blood of 53 acute leukemia children, including 25 patients in new diagnosis and 28 patients in continuous complete remission (CCR), and were compared with that of 20 normal children. The results indicated that the mean proportion of CD4(+) CD25(+) CD127(+) in CD4(+) T cells of peripheral blood in newly diagnosed patients, patients with CCR and normal children were (9.55 +/- 2.41)%, (8.54 +/- 2.51)% and (6.25 +/- 0.85)% respectively, the mean proportions of CD4(+)CD25(+)CD127(+) in newly diagnosed patients and patients with CCR were higher than that in normal children, the mean proportion of CD4(+)CD25(+)CD127(+) in newly diagnosed patients were higher than that in patients with CCR (p < 0.05). At the same time, the NK cell count in patients with acute leukaemia decreased as compared with normal control, while after achieving CCR, the NK cell count in patients were also less than that in normal control (4.11 +/- 3.87% and 10.41 +/- 7.20% vs 14.06 +/- 5.95%, p < 0.05). It is concluded that the application of CD4(+), CD25(+) and CD127(+) to detect regulatory T cells is a simple, reproductive and accurate method, and the CD4(+) CD25(+) CD127(+) T cells can better reflect the proportion of CD4(+)CD25(+) regulatory T cells. The increase of regulatory T cells and decrease of NK cells in pediatric patients with acute leukemia indicate that the function of NK cells may be depressed. Treg T cells play a role in occurrence and development of leukemia, and are involved in down-regulating NK cell function.