RESUMO
ABSTRACT The development of DBA/2J mouse strain embryos is nearly 12 h - or 6 somite pairs - delayed as compared to the outbred NMRI mouse embryos of the same age on gestation days (GD) 8-12. To evaluate inter-strain differences in susceptibility to teratogens, dams were treated with methylnitrosourea (MNU, 5 mg/kg body weight i.p.) on defined gestation days (NMRI: GD 9, 91/2 or 10; DBA/2J: GD 10 or 101/2). Skeletal anomalies produced by MNU on both mouse strains varied with the GD of treatment. The pattern of anomalies produced by MNU on a given GD markedly differed between the two mouse strains, yet they were similar -with a few exceptions- when exposures at equivalent embryonic stages are compared. Findings from this study indicated that strain-dependent differences in the developmental stage of mouse embryos of the same gestational age occur, a possibility that has been often neglected when inter-strain differences in susceptibility to developmental toxicants are interpreted.
Assuntos
Animais , Feminino , Gravidez , Ratos , Esqueleto/anormalidades , Teratogênicos/toxicidade , Somitos/anormalidades , Desenvolvimento Embrionário/efeitos dos fármacos , Embrião de Mamíferos/anormalidades , Metilnitrosoureia/toxicidade , Esqueleto/efeitos dos fármacos , Esqueleto/embriologia , Somitos/efeitos dos fármacos , Somitos/embriologia , Embrião de Mamíferos/efeitos dos fármacos , Camundongos Endogâmicos DBARESUMO
Introduction: The present study was carried out to evaluate the effect of the beta-lactam antibiotic amoxicillin on the fetuses of albino mice from the morphological and skeletal points of view
Material and methods: Twenty four adult pregnant mice were used in the present study. They were allocated into 3 groups [8 mice each]. The first group served as a control and were injected intraperitoneally [i.p.] with the solvent of the drug and the second and third groups were treated with 205 and 820 mg/kg body weight of amoxicillin for 8 days [gestation days 7-14], respectively
Results: The morphological examination of the fetuses of treated groups showed growth retardation of mice fetuses as represented by the conspicuous decrease in the average body weight and body length in the two treated groups. No external malformations were recorded among fetuses maternally treated with the low dose of the drug. On the other hand, the fetuses maternally treated with the high dose showed mild external morphological malformations. In addition, the skeleton of the two treated groups exhibited incomplete ossification in most skeletal elements
Conclusion: The beta-lactam antibiotic amoxicillin had exerted mild morphological malformations and skeletal abnormalities in mice fetuses maternally treated during organogenesis period of gestation