Granulocyte colony-stimulating factor induced reduction in pulpal necrosis

To examine the effect of recombinant granulocyte colony-stimulating factor (G-CSF) on the number and function of neutrophils and on the histopathology of pulpal inflammation in normal and neutropenic rats.

The effect of G-CSF on changes in pulpal tissue was investigated at 2, 4, 7, and 10 days after pulpal exposure of the mandibular first molar of normal rats and of those with methotrexate-induced neutropenia. The area of pulpal necrosis was measured. The neutrophil count in peripheral blood was determined, and their phagocytosis and chemotactic reaction were also examined. Statistical significance was examined by use of the two way analysis of variance.

In untreated rats, G-CSF significantly (P < 0.05) increased the number of peripheral neutrophils and their chemotactic reaction, but did not affect pulpal inflammation. In methotrexate-induced neutropenic rats, the phagocytosis and migration of neutrophils reduced, and the area of pulpal necrosis enlarged. After the G-CSF injection, the decreases in neutrophil count and their functions significantly (P < 0.05) reversed, and the enlargement of pulpal necrosis inhibited.

These findings indicate that G-CSF prevented the reduction in neutrophil function and reduced the pulpal necrosis observed in the neutropenic rats, and suggest that neutrophils defend against bacterial invasion in pulpal tissue.