The application of the reproductive engineering to study the genetic effect and maternal one on the occurrence of a spontaneous cleft lip and palate in CL/Fr mouse fetuses

通过胚胎移植实验，研究了胎重、胎株、胎重和产仔数对CL/Fr小鼠胎儿宫内颅面形态发生的影响。在妊娠第18天，对每只接受过CLP /Fr小鼠胚胎的妊娠鼠坝进行剖腹手术，取出在CLP敏感的CLP /Fr菌株坝和抗CLP的C57BL菌株坝子宫内发育的移植胎儿。随后对每个胎儿的颅面形态进行了头部测量观察。经多元回归分析，患病胎重、胎重和窝产仔数对患病CL/Fr胎儿上颌尺寸的标准化偏回归系数分别为0.71 （P< 0.01）、0.03和-0.07。最小二乘方差分析表明，除患胎体重影响外，坝体应变效应对患胎上颌尺寸和颅骨尺寸影响显著（颅骨尺寸P= 0.01，上颌尺寸P= 0.05），对患胎下颌骨尺寸影响接近显著水平（P= 0.09）。在统计消除患胎体重、胎体体重和产仔数对CL/Fr坝系发育的患胎各原始颅面尺寸的影响后，调整后的上颌尺寸和颅面尺寸也显著小于C57BL坝系发育的患胎。本研究结果表明，CLP影响的CL/Fr小鼠胎儿颅面生长与胎儿体重成正比。此外，在检查自发性CLP的病因时，除了患胎体重的影响外，大坝应变效应也不可忽视，而由CL/Fr应变坝提供的子宫环境阻碍了患胎的宫内颅面发育。由此可见，坝体应变效应和患胎体重的影响对两种坝体发育的CL/Fr型患胎颅面形态发生均有重要影响。少

Embryo transfer experiments were performed to determine the effect of the fetus weight, dam strain, dam weight and litter size on the intrauterine craniofacial morphogenesis of CL/Fr mouse fetuses. On the 18th gestational day, each pregnant dam that had received CL/Fr mouse embryos was laparotomized to remove the transferred fetuses that had developed in the uteri of the cleft lip and palate (CLP)-susceptible CL/Fr strain dam and the CLP-resistant C57BL strain dam. A cephalometric observation of the craniofacial morphology of each fetus was subsequently performed. Based on a multiple regression analysis, the standardized partial regression coefficients of the affected fetus weight, the dam weight and the litter size on the maxillary size of the affected CL/Fr fetus were 0.71 (P<.01), 0.03 and -0.07. According to a least-squares analysis of variance, the dam strain effect in addition to the effect of the affected fetus weight on the maxillary size and the cranial size of the affected fe … More tuses was significant (P=.01 for cranial size, P=.05 for maxillary size) and close to a significant level (P=.09) for the mandibular size of the affected fetuses. The adjusted maxillary size and cranial size after statistically eliminating the effects of the affected fetus weight, dam weight and the litter size on each original craniofacial size of the affected fetuses that had developed in the CL/Fr dam strain were also significantly smaller than those of the affected fetuses that had developed in the C57BL dam strain. The present results indicated that the craniofacial growth of the CL/Fr mouse fetus affected with CLP increased in proportion to the fetus weight. In addition, the dam strain effect, in addition to the effect of the affected fetus weight, could thus not be ignored when the etiology of the spontaneous CLP was examined, while the uterine environment, provided by the CL/Fr strain dam, retarded the intrauterine craniofacial growth of the affected fetuses. It was therefore concluded that the dam strain effect as well as the effect of the affected fetus weight thus both play an important role on the craniofacial morphogenesis of the CL/Fr strain of the affected fetuses that developed in both strain dams. Less