Expression of adhesion receptors on rat limb bud cells and results of treatment with a thalidomide derivative

The expression of several adhesion surface receptors was studied on cells o f early limb bud development of 58 Wistar rats treated orally with two dail y doses of the thalidomide derivative EM12 (2 x 50 mg/kg body weight) from day 7 to 10 of pregnancy. EM12 is a more potent teratogen than thalidomide. Limb bud cells of 56 untreated animals served as controls. The studies rev ealed that-the integrins CD11a, CD11b, CD18, CD49d, and CD61, as well as th e additional adhesion,receptors CD54, CD62L, and the transferrin receptor C D71 were expressed on day Il of gestation to various degrees on these embry onic cells. In contrast to results of previous studies with a non-human pri mate (Callithrix jacchus) there was no down-regulation of any of these rece ptors on the surface of limb bud cells of the rat embryos after treatment w ith EM12. This result is in accordance with the lack of teratogenicity in t his rodent species.