研究小鼠骨髓间充质干细胞（BMSCs）细胞膜上Caveolae/Caveolin-1与膜胆固醇（Chol）对BMSCs成骨分化的影响。

体外培养BMSCs，未处理细胞作为对照，对细胞进行以下干预：用甲基-β-环糊精（MβCD）处理耗竭细胞膜Chol，添加Chol补充细胞膜Chol，转染非特异性小干扰siRNA （si Ctrl）和转染Caveolin-1 siRNA （si CAV-1）。通过Amplex Red法检测各处理组细胞的Chol含量；RT-PCR与Western blot检测各组Caveolin-1表达；碱性磷酸酶活性测定和茜素红染色观察成骨细胞形成情况。多组间比较采用单因素方差分析，组间两两比较采用LSD-t检验。

与对照相比，MβCD处理细胞后Chol含量[（59.33 ± 11.24）比（127.00 ± 12.45）mmol/L]、Caveolin-1 mRNA （0.52 ± 0.05比1.00 ± 0.15）下降，ALP活性[（18.37 ± 0.31）比（10.13 ± 0.41）U/L]增强，添加Chol后细胞Chol含量[（228.21 ± 10.38）比（127.00 ± 12.45 ）mmol/L]、Caveolin-1 mRNA （4.58 ± 0.25比1.00 ± 0.15）和Caveolin-1蛋白表达（184.00 ± 10.25比51.25 ± 8.12）增加，ALP活性[（6.32 ± 0.54）比（10.13 ± 0.41）U/L]减弱（P均< 0.05）。与转染si Ctrl相比，转染si CAV-1的细胞Chol含量[（95.35 ± 14.05）比（136.00 ± 15.52）mmol/L]、Caveolin-1 mRNA （0.10 ± 0.21比1.00 ± 0.45）和Caveolin-1蛋白表达（6.12 ± 0.35比13.06 ± 1.52）下降，ALP活性[（19.28 ± 0.34）比（10.15 ± 0.43）U/L]增强（P均< 0.05）。茜素红染色显示，MβCD处理和转染si CAV-1使BMSCs基质矿化增加，而添加Chol使BMSCs基质矿化减少。

Caveolae/Caveolin-1与膜Chol相互影响并共同调控小鼠BMSCs成骨分化。

To investigate the effect of Caveolae/Caveolin-1 and membrane cholesterol on the osteogenic differentiation of mouse bone marrow mesenchymal stem cells (BMSCs) .

BMSCs were cultured in vitro and untreated cells as the control. The following interventions were performed on the cells: depletion of membrane cholesterol using methyl-β-cyclodextrin (MβCD) , supplementation of membrane cholesterol, transfection with non-specific small interfering RNA (si Ctrl) and Caveolin-1 siRNA (si CAV-1) .The Amplex Red method was used to detect the Chol content in the cells of each treatment group. RT-PCR and Western blot were used to detect the expression of Caveolin-1 in each group. Alkaline phosphatase (ALP) activity assays and alizarin red staining were performed to observe osteoblast formation. One-way analysis of variance was used for multi-group comparisons, and the LSD-t test was used for pairwise comparisons between groups. P < 0.05 was considered statistically significant.

Compared to untreated cells, treatment with MβCD led to a decrease in cholesterol [ (59.33 ± 11.24) vs (127.00 ± 12.45) mmol/L], Caveolin-1 mRNA (0.52 ± 0.05 vs 1.00 ± 0.15) , as well as an increase in ALP activity [ (18.37 ± 0.31) vs (10.13 ± 0.41) U/L] (P < 0.05) . Addition of cholesterol resulted in an increase in cholesterol [ (228.21 ± 10.38) vs (127.00 ± 12.45) mmol/L], Caveolin-1 mRNA (4.58 ± 0.25 vs 1.00 ± 0.15) , and Caveolin-1 protein expression (184.00 ± 10.25 vs 51.25 ± 8.12) , as well as a decrease in ALP activity [ (6.32 ± 0.54) vs (10.13 ± 0.41) U/L] (P < 0.05) . Compared to cells transfected with si Ctrl, cells transfected with si CAV-1 showed a decrease in cholesterol [ (95.35 ± 14.05) vs (136.00 ± 15.52) mmol/L], Caveolin-1 mRNA (0.10 ± 0.21 vs 1.00 ± 0.45) , and Caveolin-1 protein expression (6.12 ± 0.35 vs 13.06 ± 1.52) , as well as an increase in ALP activity [ (19.28 ± 0.34) vs (10.15 ± 0.43) U/L] (P < 0.05) . Alizarin red staining showed that treatment with MβCD and transfection with si CAV-1 increased mineralization of the BMSCs matrix, while the addition of cholesterol decreased mineralization.

Caveolae/Caveolin-1 and membrane cholesterol mutually influence and co-regulate the osteogenic differentiation of mouse BMSCs.