EFFECT OF LEAD ON BONE AND CARTILAGE IN SEXUALLY MATURE RATS - A MORPHOMETRIC AND HISTOMORPHOMETRY STUDY

The effect of exposure to lead on the longitudinal development of the femur and of its cartilage growth plate was studied in rats. A group o f forty-five 50-day-old female Wistar rats was divided into a control group of 20 rats and an experimental group of 25 rats fed a diet suppl emented with 17 mg of lead acetate per kilogram of feed for 50 days. O n Day 50 all rats were killed and their right femurs were dissected. T he femurs were cleaned of soft tissue and femoral lengths were measure d with a Vernier caliper and thickness of growth cartilage (GPC-Th mu m) by histomorphometry. Final body weights were significantly (P < 0.0 5) lower in the control group than in the rats given the lead-suppleme nted diet. Femur length did not differ between groups. Histomorphometr y of the femur showed that the thickness of growth cartilage was highe r (P < 0.05) in the control group. These findings suggested lead-induc ed inhibition of growth plate development. The growth plate may be one of the key target tissues accounting for the adverse effects of chron ic lead exposure on skeletal development. (C) 1997 Academic Press.