The Effects Of Pioglitazone On Proliferation,apoptosis And Expressions Of Functional Protein OCN,ALP,BMP2 In MC3T3-E1 Preosteoblasts Exposed To High Glucose State

Objective:The aims of this study were to assess the effects of pioglitazone (PIO) on proliferation, apoptosis, secretion and expressions of functional protein of MC3T3-E1 preosteoblasts which were exposed to constant high glucose condition, and try to explore the possible mechanisms.Methods:The mouse preosteoblasts MC3T3-E1 cultured in vitro were divided into four groups (0, 2.5, 5.0 and 10.0μmol/L separately), and intervened with different concentrations of PIO for 24 and 48 hours. CCK-8 was taken to test the cell proliferation inhibiting rate. Annexin V-FITC/PI double staining flow cytometry was used to detect the cells apoptosis quantitatively. The levels of osteocalcin (OCN) and alkaline phosphase (ALP) in supernatant were measured by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (Elisa) separately. The transcription of peroxisome proliferator-activated receptor gamma (PPARγ),runt related gene 2 (Runx2) and bone morphogenetic protein 2 (BMP2) mRNA was detected by semi-quantity reverse transcription polymerase chain reaction (RT-PCR).Results:1. The treatment groups showed an obvious decrease in proliferation inhibiting rate at the same intervening time (P<0.05). The effect of proliferation inhibition was significantly correlated with the concentration of drug (2.5~10.0μmol/L) and intervening time (P<0.05).2. The early apoptosis rates of the treatment groups compared with the control group were significantly higher (P<0.05). The early apoptosis rate of each group were respectively(12.37±1.19)%,(39.33±0.67)%,(59.97±0.81)%,(81.87±0.15)%. Groups test showed a significant difference between them (P<0.05).3. Within the treatment groups, increasing concentrations of PIO increased the expression of PPARγin a dose-dependent manner. While for osteoblast-specific transcription factor Runx2, the situation is just the reverse(P<0.05).4. At the same intervening time point,the expression and secretion of cell function protein OCN, ALP, BMP2 were significantly lower in treatment groups than control group (P<0.05). Increasing concentrations of PIO decreased the expression of them in a dose-dependent manner, while groups test showed an significantly difference between each other (P<0.05).Conclusions:1. Suitable concentration of PIO suppressed the proliferation and induced the apoptosis of MC3T3-E1 preosteoblasts which exposed to high glucose condition, and inhibited the expression and secretion of functional protein OCN, ALP and BMP2 in a dose-dependent manner.2. PIO may via up regulating PPARγexpression, suppressing osteoblast-specific transcription factor Runx2 expression and related bone formation signaling pathways to exert its functions that mention above.3. In the condition of high glucose, low concentrations of PIO (2.5μmol/L) can be toxic to cells. TZD may increase the risk of osteoporosis suffering or aggravating from diabetes.