Methacrylic acid as a teratogen in rat embryo culture.

Using day 10 rat embryos cultured in vitro, we have shown that methacrylic acid is teratogenic at concentrations ranging from 1.2 to 2.1 mM. At these concentrations, methacrylic acid produced concentration-dependent decreases in growth parameters, i.e., crown-rump length, number of somites, and embryo protein content. In addition, methacrylic acid exposure produced malformed embryos characterized primarily by abnormal neurulation. Less frequent abnormalities included hypoplasia of the prosencephalon, edema, malpositioned heart, abnormal flexion, and dilated otic vesicles. Accompanying these abnormalities was an underlying increase in methacrylic acid-induced cell death.