Wound healing in the fetal period: the resistance of the scar to rupture.

Wound healing in the fetal period is fundamentally different from that of the adult. In order to better understand this difference, we have studied wound healing in three types of wounds which are the most common in surgical practice, and have paid special attention to tensile strength in the scar. A sutured wound, a nonsutured wound, and an electrocautery burn were performed on a group of 30 rabbit fetuses with a gestational age of 23 days. Seven days later, the resulting scars were examined using histological, mechanical, and biochemical studies. The results were compared with those obtained in a group of 30 newborn rabbits and in a group of 30 adult rabbits who had had the same type of wounds performed on them. The body weight of operated fetuses was smaller than their control siblings. The sutured wound in the fetuses showed a more perfect macroscopic repair than in older subjects. However, the nonsutured wounds and the burns of the fetal group did not close. In the fetuses, the tensile strength of the sutured wound was 20% of the tensile strength of healthy skin. A similar relationship occurred in the group of adult rabbits. In the sutured wound of the fetal group, the synthesis of collagen was significantly less than in the adult group. The ratio between hydroxyproline (HYP) concentration in the sutured wound and HYP concentration in healthy skin was also significantly less in the fetal group than in the adult group.(ABSTRACT TRUNCATED AT 250 WORDS)