Quantitation of phagocytic cells in phenytoin-induced connective tissue proliferation in the rat

This study demonstrates that, in rats, systemically administered phenytoin produces a statistically significant increase in accumulation of phagocytic and esterase positive cells in areas of phenytoin-induced connective tissue proliferation. Many of these cells are perceived to be macrophages. Since macrophages have been shown to produce chemoattractant and mitogens for fibroblasts, they may very well play a major role in the gingival hyperplasia seen in patients taking phenytoin. The results of the study show that the effects of phenytoin on fibroblasts may be more complex than previously thought.