Objective To investigate the effects of tannic acid (TA) doping on the physicochemical properties, biocompatibility, in vitro osteogenic performance, and antibacterial activity of Brushite bone cement, and to evaluate its feasibility for bone defect repair. MethodsTA was incorporated into Brushite bone cement at concentrations of 0, 1.0, 3.0, 5.0, and 10.0 mg/g of solid powder, designated as Brushite, Brushite/TA-1, Brushite/TA-2, Brushite/TA-3, and Brushite/TA-4, respectively. The compressive strength and microstructure of each group were evaluated. The extracts of the bone cements were prepared and co-cultured with MC3T3-E1 cells. Cell proliferation was assessed using the cell counting kit 8 (CCK-8) assay. The cytotoxicity was observed by Calcein/propidium iodide live/dead cell staining. Cell adhesion was observed via scanning electron microscopy. After osteogenic induction, alkaline phosphatase (ALP) activity was measured and ALP staining was performed. The expression levels of osteogenic-related genes, including runt-related transcription factor 2 (Runx2), osteocalcin (OCN), osteopontin (OPN), collagen type Ⅰ (Col-Ⅰ), and integrin-binding sialoprotein (IBSP), were detected by real-time fluorescent quantitative PCR (qRT-PCR). The antibacterial activity of the bone cement against Escherichia coli was assessed using the inhibition zone method. ResultsCompared with the Brushite group, the Brushite/TA-3 and Brushite/TA-4 groups exhibited significantly increased compressive strength (P<0.05). TA doping resulted in a higher crystal content and a more regular and dense crystal arrangement. Regarding cytocompatibility, the Brushite/TA-3 group demonstrated the most pronounced enhancement of cell proliferation (P<0.05), whereas the Brushite/TA-4 group showed relatively lower cell proliferative activity (P<0.05). All groups exhibited low cytotoxicity with good cell viability. Cell adhesion density and pseudopodia extension were superior in all TA-doped groups compared with the Brushite group. Regarding osteogenic activity, after 14 days of osteogenic induction, ALP activity was higher in all TA-doped groups than in the Brushite group (P<0.05) in a dose-dependent manner. The relative expression of Runx2, OCN, OPN, Col-Ⅰ, and IBSP mRNA also increased to varying degrees in a dose-dependent manner compared with the Brushite group. Regarding antibacterial performance, only the Brushite/TA-4 group exhibited inhibitory effects against Escherichia coli, with an inhibition zone diameter of approximately 7 mm. ConclusionDoping with an appropriate concentration of TA (3.0-5.0 mg/g) improves the mechanical properties, cytocompatibility, and osteogenic activity of Brushite bone cement. A higher concentration (10.0 mg/g) confers antibacterial properties but may partially inhibit cell proliferation. TA-doped Brushite bone cement demonstrates good application potential in the field of bone defect repair.
Objective To study the therapeutic effect of Roux-en-Y gastric bypass （RYGB） on type 2 diabetes mellitus （T2DM） rats and explore the possible mechanism of vaspin in RYGB on T2DM. Methods Twenty SD rats with T2DM and 20 age- and sex-matched normal SD rats were randomly divided into 4 groups according to the random digits table：T2DM-RYGB group， T2DM-sham operation （SO） group，RYGB group，and SO group，10 rats in each group. Fasting plasma glucose （FPG） level，serum insulin （INS） level，vaspin level，and homeostasis model of insulin resistance （HOMA-IR） were determined before operation and on week 4，8 after operation，respectively．At the same time，the correlation between vaspin and the indicators （FPG，INS，or HOMA-IR） was analyzed．Results Compared the indicators after operation with before operation，the FPG level，INS level，vaspin level，and HOMA-IR were not significantly different between the T2DM-RYGB group and T2DM-SO group （P＞0.05） or between the RYGB group and SO group （P＞0.05），but the FPG level，INS level，vaspin level，and HOMA-IR in the T2DM-RYGB group and T2DM-SO group were significantly higher than those in the RYGB group （P＜0.05） and SO group （P＜0.05），respectively. On week 4 after operation，the FPG level，INS level，vaspin level，and HOMA-IR decreased in the T2DM-RYGB group，except for the FPG level，the other indexes had no significant differences as compared with the values before operation. On week 8 after operation，the FPG level，INS level，vaspin level，and HOMA-IR further decreased in the T2DM-RYGB group，there were significant differences of these indicators between before operation and on week 8 after operation. Compared the indicators after operation with before operation，the FPG level，INS level，vaspin level，and HOMA-IR were not statistically significant （P＞0.05） in the T2DM-SO group，RYGB group，or SO group. The changes in serum vaspin level correlated positively with those in INS and HOMA-IR before operaion and on week 4，8 after operaion in the T2DM-RYGB group and T2DM SO group rats （P＜0.05），respectively. Conclusions RYGB surgery has a therapeutic effect on T2DM rats，and serum vaspin level decreases and insulin resistance is improved after RYGB surgery，which may be one of the mechanisms of the treatment for T2DM.
