Assessment of Teratogenic Effects of Lidocaine in Rat Embryos Cultured In Vitro

Background Lidocaine has been reported to cause neural tube closure defects in vitro in mice at clinically relevant concentrations. However, no studies have been conducted to further investigate this potentially hazardous effect of lidocaine. This study was aimed to reassess teratogenic effects of lidocaine in vitro in rats. Methods Sprague-Dawley rat embryos were explanted at 8:00 AM on gestational day 9 and were cultured in medium containing various concentrations of lidocaine. (Embryos in the control group were cultured without lidocaine). After 50 h of culture, they were evaluated for growth size and morphology, including the neural tube closure. Results In the presence of 250 microM of lidocaine, embryos showed a increased incidence of situs inversus compared with control group but were otherwise normal. At 375 microM, embryos showed slight growth retardation but no significant morphologic abnormalities. At 500 microM, all viable embryos showed severe morphologic abnormalities. However, morphologic abnormalities were so-called nonspecific types and neural tube closure defects were not observed. Conclusions Results from the current study indicate that lidocaine causes teratogenic effects in vitro in rats only at concentrations much higher than clinically relevant concentrations. Furthermore, lidocaine did not cause neural tube closure defects at any concentrations evaluated.