目的 探讨孕期雌鼠摄入超量咖啡因对胎鼠软骨内骨化的影响及其分子机制。  方法  在孕第9～20 天，咖啡因暴露组Wistar孕鼠每天灌胃120 mg/kg咖啡因，对照组灌胃相同体积的蒸馏水。将孕20 d的孕鼠脱颈处死，取出胎鼠，测量两组胎鼠体长；分离胎鼠股骨远端，测量股骨远端软骨长度，并制备原代软骨细胞，分别用咖啡因（0.1、1和10 μmol/L）、胰岛素样生长因子1（IGF-1，100 μg/L）和细胞外调节蛋白激酶（ERK）抑制剂（10 μmol/L）进行处理，收获细胞进行凋亡、mRNA和蛋白质分析。   结果  与对照组相比，咖啡因暴露组胎鼠的体长和股骨长均显著下降（P<0.05），血清皮质酮水平显著提高（P<0.05）。咖啡因暴露组胎鼠软骨细胞肥大区的IGF-1、增殖细胞核抗原（PCNA）和性别决定区Y框蛋白9 (SOX9)表达均较对照组显著降低（P<0.05）。在体外实验中，咖啡因处理以剂量依赖性的方式降低了原代软骨细胞中IGF-1、PCNA、SOX9 mRNA和p-ERK蛋白表达，外源性-IGF-1 则能逆转咖啡因诱导的这些变化，而外源性IGF-1的作用则被ERK抑制剂降低（均P<0.05）。   结论  产前咖啡因暴露通过抑制软骨细胞增殖导致胎鼠股骨远端变短，软骨细胞肥厚区延长。软骨细胞中的IGF-1/MAPK/ERK信号通路可能部分参与咖啡因对软骨细胞增殖的不利影响。

Objective  To investigate the effect of excessive caffeine intake on fetal cartilage ossification in female rats during pregnancy and its mechanism.    Methods  From gestational day(GD) 9 to GD 20, the pregnant Wistar rats in caffeine exposure group were intragastrically administered 120 mg/kg day caffeine, and the control group was administered the same volume of distilled water. The pregnant mice were sacrificed at day 20, and the body length of the fetal mice was measured. The distal femur of fetal rats was isolated, the length of distal femur cartilage was measured, and primary chondrocytes were prepared. The cells were treated with caffeine (0.1, 1 and 10 μmol/L), insulin-like growth factor 1 (IGF-1, 100 μg/L) and extracellular regulated protein kinases（ERK）inhibitor (10 μmol/L), respectively. Then the cells were harvested for apoptosis, gene and protein analysis.    Results  Compared with the control group, the body length and femur length of the fetuses in the caffeine exposed group decreased significantly (P<0.05), and the serum corticosterone levels increased significantly (P<0.05). Immunohistochemical analysis showed that the expressions of IGF-1, proliferating cell nuclear antigen (PCNA) and sex determining region Y box protein 9(SOX9) in mast chondrocyte area of caffeine exposed group were significantly lower than those of control group (P<0.05). In vitro, caffeine treatment reduced the expression of IGF-1, PCNA, SOX9 mRNA and p-ERK protein in primary chondrocytes in a concentration-dependent manner, while exogenous IGF-1 could reversed these changes induced by caffeine, and the effect of exogenous IGF-1 was reduced by ERK inhibitors (all P<0.05).    Conclusion  Prenatal caffeine exposure leads to shortening of the long bones of the fetus and prolongation of the hypertrophy by inhibiting the proliferation of chondrocytes. The IGF-1/MAPK/ERK signaling pathway in chondrocytes may be partially involved in the adverse effects of caffeine on chondrocyte proliferation.