Polarization microscopy of picrosirius red-stained collagen from oxodipine-induced hyperplastic gingiva of beagle dogs.

Using the model of oxodipine-induced gingival hyperplasia in beagle dogs, we investigated the collagen fibres of the hyperplastic gingiva by measuring the polarization colours from Picrosirius-red stained sections. The predominant polarization colours of the thick collagen fibres (1.6-2.4 microns diameter) of male oxodipine-treated dogs were greenish-yellow to yellow, while in controls and in female oxodipine-treated dogs, the same size fibres mostly appeared orange and red. These differences may be indicative of gender variation in the genesis of hyperplastic gingiva in calcium channel blocker treated dogs.