Squamous epithelial proliferation in the jaws of mink fed diets containing3,3 ',4,4 ',5-pentachrorobiphenyl (PCB 126) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Previous research has shown that ingestion of 3,3',4,4',5-pentachlorobiphen yl (PCB 126) by juvenile mink (kits) caused a lesion in the mandible and ma xilla that consisted of proliferation of squamous epithelium in the periodo ntal ligament, osteolysis of adjacent alveolar bone, and loose and displace d teeth. Similar, but less severe changes, developed in adult mink Fed 2,3, 7,8-tetrachlorodibenzo-p-dioxin (TCDD). The present study was conducted to compare similarities and differences of the lesion within the jaws of mink Fed these 2 polyhalogenated hydrocarbons. Diets containing 24 ppb PCB 126 o r 2.4 ppb TCDD were fed to 6-w-old kits for 36 d. Similar diets were fed to 12-w-old kits for 35 d. Some of these mink were then Fed untreated feed fo r an additional 50 d. All mink treated with PCB 126 or TCDD had reductions in body weight gains which were more severe in the 6-w-old kits than the 12 -week-old kits. BY 28 days of exposure, many of the 6- and 12-week-old mink treated with PCB 126 or TCDD had loose and displaced incisor teeth. Canine teeth were grossly more prominant. Radiographs showed maxillary and mandib ular osteolysis with lysis of the lamina dura in treated mink. Withdrawal o f the toxicants From the diets of the 12-w-old mink failed to alleviate the lesions, which continued to be progressively more severe.