Table 1. Rescue of E10.25 Raldh2-/- embryos by various retinoids.
| Retinoid | Dose, mg/kg | Total no. of embryos | No. of +/+ or -/+ | No. of -/- unrescued | No. of -/- rescued | Teratogenesis* |
|---|---|---|---|---|---|---|
| All-trans-RA | 1.0 | 19 | 12 | 7 | 0 | 0 |
| All-trans-RA | 2.5 | 41 | 27 | 1 | 13 | 0 |
| 9-cis-RA | 2.5 | 30 | 20 | 8 | 2(partial) | 0 |
| 9-cis-RA | 10 | 30 | 23 | 1 | 6 | 0 |
| SHet100 | 0.025 | 11 | 9 | 2 | 0 | 0 |
| SHet100 | 0.25 | 10 | 8 | 0 | 2(partial) | 0 |
| SHet100 | 0.5 | 20 | 13 | 1 | 6 | 0 |
| SHet100 | 2.5 | 11 | — | — | — | 11 |
| OHet72 | 2.5 | 8 | 4 | 4 | 0 | 0 |
| OHet72 | 10 | 19 | 16 | 3 | 0 | 0 |
| OHet72 | 25 | 17 | 12 | 5 | 0 | 0 |
| SHetA2 | 2.5 | 8 | 7 | 1 | 0 | 0 |
| SHetA2 | 10 | 18 | 13 | 5 | 0 | 0 |
| SHetA2 | 25 | 7 | 6 | 1 | 0 | 0 |
Embryos indicated as +/+ (wild-type) or -/+ (Raldh2-heterozygous) were normal in appearance with RARE-lacZ expression throughout trunk mesoderm, whereas -/- (Raldh2-homozygous) unrescued embryos were much smaller and failed to undergo axial rotation, and -/- rescued embryos were normal in size but with growth-retarded forelimb buds and no RARE-lacZ expression in somites or lateral plate mesoderm
*
Teratogenesis was reported as positive after observation of an obvious growth defect or malformation in +/+ or -/+ embryos. In the single instance where teratogenesis is indicated, all embryos in that litter failed to undergo axial rotation and were stalled between stages E8.5 and E9.0