Effects of Brain Cautery on Fetal Development in the Rat

The primary purpose of this study is to determine whether the fetus can survive extensive damage to the brain, and the possible effects of brain injury on subsequent growth and development. Previous studies have been almost entirely confined to observations on teratological (anencephalic) human material (Preyer, 1 Bruns et al., 2 Nañagas, 3 Marcus and Nickman 4 ).

Destruction of portions of the fetal brain (rat∗) was accomplished by means of the electric cautery. No repair was found necessary other than suture of the maternal body wall (Nicholas 5 ). Fetuses recovered from the uterus or taken at birth subsequent to such procedure were examined as to behavior, measured, weighed and placed at once in 5% formalin preparatory to microscopic study of the injured area. Unoperated litter-mates served as controls, A series of control experiments involved (a) injection of carbon ink into the ventricles of the brain, and (b) extensive cautery of an extremity. Seventy fetuses from 21 litters comprise the experimental material, and 36 fetuses from 10 litters were used in the control experiments.

Of the 70 operated fetuses ranging between 11 and 37 mm. of crown-rump length at operation, 40 survived until term or were recovered alive from the uterus 1, 2, 3, 4, 5, or 6 days following cautery. The remainder were either aborted (2) or partially resorbed. At term (39 to 42 mm.) 11 fetuses died in utero and none of the animals survived parturition more than 24 hours. The rat fetus may survive brain cautery until term regardless of the stage of development at which the operation is performed.