Localization and changes in superoxide dismutase immunoreactivity in rat pulp after tooth preparation

Objective. To examine the distribution of superoxide in the uninflamed and inflamed dental pulp by characterizing the immunoreactivity of the detoxify ing antioxidant enzymes, manganese and copper-zinc superoxide dismutases (M nSOD and CuZnSOD, respectively). Study design. In 12 rats, mesial cavity preparations were made on the maxil lary right first molar; left molars were unoperated controls. After 5 days, the rats were killed, and histologic sections were processed by using MnSO D and CuZnSOD immunoreactivity, and the extent of inflammation was evaluate d on alternate sections stained with hematoxylin and eosin. Results. In the hematoxylin and eosin-stained sections, inflammation was co nsistent with : macrophages, lymphocytes, and plasma cells that coalesced i nto a distinct leukocytic "lesion," which obliterated portions of the under lying pulp. Both MnSOD and CuZnSOD immunoreactivity increased dramatically in inflammatory cells within the leukocytic lesion and in the tissue surrou nding the lesion. Conclusions. The findings suggest that the protective role of SOD increases within pulp cells that are undergoing inflammatory stimulation. SOD immuno reactivity may be an early indicator of stress in pulp.