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To compare the proliferation and osteogenic differentiation of osteoblasts between newborn rats (1d group) and two-week-old rats (14d group) and to clarify the mechanism underlying these effects.The endogenous expression of osteogenic marker genes was detected by qPCR, including ALP, OCN, Col1a1, and Runx2. The osteoblasts proliferation was evaluated by EdU assay and Western Blotting [PCNA and Cyclin D1]. ALP activities in osteoblasts were detected using a PNPP kit, ALP staining and qPCR. Mineralized nodule formation and intracellular calcium levels were assessed by Alizarin Red staining and calcium colorimetric assay respectively while OCN, Col1a1 and Runx2 levels in osteoblasts were analyzed by immunostaining. Osteogenesis-associated pathways including Wnt/β-Catenin, Akt/PPAR and Smad were analyzed via Western Blotting.Endogenous ALP, OCN, Col1a1, and Runx2 expression levels were significantly higher in osteoblasts from 14d group than those from 1d group. After treatment with osteogenic induction medium, osteoblast proliferation, ALP activity, mineralized nodule formation, and intracellular calcium levels were markedly increased in osteoblasts from 1d group, with similar results also being observed for the expression of OCN, Col1a1, and Runx2. Wnt3a, β-catenin, p-Akt, p-Smad1/5/8, and p-Smad5 protein levels were also higher in osteoblasts from 1d group relative to those from 14d group, while the expression of PPARγ was lower.The superior osteogenic differentiation capacity in osteoblasts was associated with the higher activation levels of Wnt/β-Catenin, Akt/PPAR and Smad signaling pathways, and the enhanced proliferative activity in osteoblasts from 1d group.

To investigate the effects of serum containing Gumibao (Chinese character: see text) on the proliferation and differentiation of osteoblast induced by dexamethasone.Osteoblasts were extracted from skulls in newly born (within 24 hours) SD rats, and digested with collagenase. The first passage of cells were used for experiments. Cells were cultured in the medium containing different concentrations of dexamethasone (0, 10(-8), 10(-7), 10(-6), 10(-5) ,10(-4) mol/L). Alkaline phosphatase staining were carried out after 1 week and numbers of mineralized nodes with alizarin red staining were observed after 3 weeks. Accordingly, following the treatment of 10(-5) mol/L dexamethasone for 1 week, cells were cultured in the medium with serum containing Gumibao (Chinese character: see text). One week after Cumibao (Chinese character: see text) treatment, cells were stained with Alkaline phosphatase and collagen I and PCNA were examined by Western-blot. However, the observation of numbers of mineralized nodes with alizarin red stain required one more week.High concentration of dexamethasone could inhibit the expression of PCNA, collagen I, alkaline phosphatase and reduce the number of mineralized nodes of osteoblast, while serum containing Gumibao (Chinese character: see text) could reverse the inhibition.High concentration of dexamethasone could inhibit the proliferation and differentiation of osteoblastic cells, while serum containing Gumibao (Chinese character: see text) could reverse the inhibition.

To investigate regulation function of anodonta glucan HBP-A on chondrocytes through Wnt pathway in vitro.Rat chondrocytes were cultured and differentiated induced with IL-1beta (10 ng/ml) in vitro. Chondrocytes were divided into five groups:IL-13 group,IL-1beta + IWP-2 (5 microM,Wnt pathway inhibitor) group, IL-1beta + HBP-A (0.3 mg/ml) group and IL-1beta + IWP-2 + HBP-A group. Wnt-3a, beta-catenin (24 h,48 h,72 h) and MMP-13(72 h) genes expression were detected by Rt-PCR, while beta-catenin, MMP-13, Sox-9 and coll-II (48 h) protein expression were measured by Western-blot.After induction of IL-1beta, gene expression of Wnt-3a, beta-catenin and MMP-13 were increased,so were the protein expression of beta-catenin and MMP-13. In contrast,protein expression of Sox-9 and Coll-II were declined. Following addition of HBP-A, Wnt-3a, beta-catenin and MMP-13 were shown as induction of IL-1beta, but protein expression of Sox-9 and Coll-II were upgraded. Combining HBP-A with IWP-2 led to the lowest level in Wnt-3a, beta-catenin gene and beta-catenin protein expression and highest expression of Sox-9 protein.HBP-A could not only delay the differentiation of chondrocytes through downgrading the signal expression of Wnt/beta-catenin,but also adjust the expression of Wnt-3a, beta-catenin and Sox-9 when combinated with the Wnt inhibitor.

To investigate the effects of osthole on proliferation of neonatal rat osteoblast and the mechanism.Ten 24 hours old SD rats were executed by dislocating. The cranium of rats were removed and cut into blocks of 1 mm x 1 mm size. After digested by trypsin for 15 min, the cranium were digested by type I collagenase for one hour two times. The mixed cells were cultured in thermostat incubator with 5% CO2 under the condition of 37 degrees C. To identify the cells, ALP staining and alizarin red staining were performed after cultured 48 h and 28 d. The osteoblasts were randomly divided into five groups. Cells were treated with osthole at concentrations of 100, 50, 25, 12.5, 0 micromol/L. CCK-8 method was used to evaluate the proliferation after 24 h,48 h and 72 h. The expression of PCNA and beta-catenin protein were detected through the method of Western Blot after one week.The cells had irregular shapes and showed typical features of osteoblast. The results of ALP staining and alizarin red staining were both positive. CCK-8 detection showed that the osthole with final concentration of 100 micromol/L inhibited the proliferation of osteoblast after 24 h, while the osthole with final concentrations of 50 micromol/L and 25 micromol/L displayed the inhibition effect after 48 h. The osthole of 12.5 micromol/L had no obvious influence on the proliferation of osteoblast. The result of Western Blot showed that osthole reduced the expression of PCNA and beta-catenin protein in a dose-dependent manner.The osthole with final concentrations of 100, 50, 25 micromol/L inhibited the proliferation of osteoblast (P0.05). The osthole with final concentrations of 12.5 micromol/L had no obvious influence on the proliferation of osteoblast (P0.05). These findings demonstrate that osthole may inhibit the proliferation of osteoblast by regulating the Wnt/beta-catenin signaling in osteoblast.