18号染色体三体NMRI小鼠发育畸形的实验研究

An experimental study on the developmental malformations of the trisomy 18 NMRI mice

目的 通过对 18三体在 NMRI小鼠发生率的研究及 18三体胚鼠和正常胚鼠的大体形态学对照观察 ,进一步认识 18三体 NMRI小鼠的生长发育畸形。方法 6 0只 Han- NMRI母鼠及 11只具有 Rb(2 .18) 6 Rma/ Rb(1.18) 10 Rma染色体结构的雄鼠 ,分别在妊娠第 16和 17天随机分两组断颈处死母鼠 ,6 0只母鼠共有 82 3只子代胚胎着床 ,其中 5 6 9只为活胚。并对所获得的子代活胚进行染色体分析和大体形态学观察。结果 染色体分析发现 5 6 9只活胚中 95只为三体 ,其中 6 8只 18三体小鼠伴有先天性腭裂。 18三体 NMRI小鼠伴有明显的脊柱弯曲 ,此外尚有脐疝、四肢短缩和短颈畸形等少见畸形 ,极个别伴脑外露畸形。结论 18三体 NMRI小鼠的生长发育畸形是一种先天性的发育畸形综合征 ,不仅有体重的发育不足 。

Objective To study the incidence of trisomy 18 in NMRI mice and its developmental malformations. Methods Sixty female NMRI mice and 11 male mice with the Rb(2.18) 6 Rma and Rb (1 18) 10 Rma chromosomes were used. On the gestational days 16 and 17, the pregnant mice were randomly killed by cervical dislocation. A total of 823 implants were gained from 60 litters; they comprised 569 living foetuses, and chromosomal examination was performed in the generated living foetuses. Gross morphological study was performed in all living foetuses. Results Ninety five foetuses were identified as trisomic foetuses in all of 569 living foetuses. Among them, there were 68 trisomy 18 NMRI mice with cleft palate. Gross morphological study showed that trisomy 18 foetuses had significant body flexion. Some cases of trisomy 18 showed shortened limbs, oedematous body or exencephaly as additional symptoms. Conclusion Developmental malformations in trisomy 18 NMRI mice showed a series of abnormalities; they had not only the underdeveloped body weight, but also the higher incidence of congenital cleft palate.