Proliferation of maxillary and mandibular periodontal squamous cells in mink fed 3,3 ',4,4 ',5-pentachlorobiphenyl (PCB 126)

This report characterizes squamous cell proliferation in young farm mink (M ustela vison) fed a diet supplemented with 0.024 ppm 3,3',4,4',5-pentachlor obiphenyl (polychlorinated biphenyl [PCB] congener 126). One to 2 months of dietary exposure to PCB 126 resulted in gross lesions of the upper and low er jaws consisting df mandibular and maxillary nodular proliferation of the gingiva and loose teeth. The maxilla and mandible of the PCB-treated mink were markedly porous because of loss of alveolar bone. Histologically, this osteoporosis was caused by proliferation of squamous cells that formed inf iltrating cords. This report clearly documents the fact that the environmen tal contaminant PCB 126 can cause osteoinvasive squamous proliferation in y oung mink, although the dose used in the present study was 7 and 36 times h igher than what is typically encountered in contaminated bird eggs and fish , respectively.