Morphology-Based Whole Embryo Culture for Developmental Toxicity of Drugs

Assessment of embryo morphology following perinatal exposure to aspirin, ibuprofen and paracetamol using whole embryo culture system

BACKGROUND

Recent evidence from a meta-analysis indicates that maternal prenatal exposure, single or repeated, to non-steroidal anti-inflammatory drugs (NSAIDs) or non-opioid painkillers, is associated with increased risk of cerebral palsy and cognitive-behavioral disorders in offspring. One potential route of action is interference with the neurulation process and hence early brain development.

OBJECTIVE

To examine the effect of prenatal exposure to common NSAIDs and non-opioid drugs on neurulation using an in vitro whole embryo culture system.

METHODS

Mouse embryos from in-bred Institute of Cancer Research albino strain mice were exteriorized on embryonic day 7.5 and cultured for 48 h in either 1 mL heat-inactivated rat serum + 0.1% dimethyl sulfoxide ("Control") or 1 mL of rat serum supplemented with six increasing concentrations of laboratory-grade aspirin, paracetamol, and ibuprofen ("Experimental"). After culture, embryo morphological and developmental parameters were documented using standardized scoring systems at each dosage concentration. The assessed concentration in rat serum culture ranged from 1.23 to 13.57 mg/mL for aspirin and 0.06-4.93 mg/mL for paracetamol and ibuprofen. The equivalent respective human dosages were 600-6600 mg and 30-2400 mg.

RESULTS

Between-group comparisons ("Control" vs "Experimental") and post-hoc pair-wise tests, adjusted for multiple comparisons, indicating no statistically significant effect on crown-rump length (p > .21), head length (p > .28), somite number (p > .25), incidence of absent hindlimb buds (p > .18), yolk sac circulation score (p > .07) and posterior neuropore closure (p > .35) in the aspirin, paracetamol and ibuprofen experiments. All embryos had forelimb buds, closed anterior neuropores and none had neural tube defects.

CONCLUSION

This study has demonstrated that there are no safety concerns regarding high-dose aspirin, ibuprofen, and paracetamol on mice's embryonic development.

Establishment of an in vitro method of rabbit embryo toxicity with toxicokinetics study

This report introduces a novel method, rabbit whole embryo culture (WEC) combined with toxicokinetics (TK), for toxicity testing. Rodent WEC has been extensively used for in vitro screening of developmental toxicity. To improve the reliability of in vitro data, it is important to consider TK and species specificity. To test the utility and effectiveness of this method, we investigated the toxic effect of thalidomide on rabbit embryos and its behavior in test systems both in vitro and in vivo under the same experimental condition. The data showed that thalidomide induced embryo malformations such as embryonic brain hypoplasia, short limb buds, and declined embryonic growth both in vitro and in vivo. The toxic effect increased with the increasing exposure of the embryo to thalidomide. In addition, we observed similar toxic effects and exposure-effect relationships in vivo and in vitro. Therefore, we preliminarily conclude that this new method can effectively predict and explain thalidomide toxicity. Furthermore, we investigated the behavior of test compounds in the WEC system for the first time, and this method is expected to be an important technique for in vitro toxicity study after extensive verification.