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 of 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 supplemented with 17 mg of lead acetate per kilogram of feed for 50 days. On Day 50 all rats were killed and their right femurs were dissected. The femurs were cleaned of soft tissue and femoral lengths were measured with a Vernier caliper and thickness of growth cartilage (GPC-Th micron) by histomorphometry. Final body weights were significantly (P < 0.05) lower in the control group than in the rats given the lead-supplemented diet. Femur length did not differ between groups. Histomorphometry of the femur showed that the thickness of growth cartilage was higher (P < 0.05) in the control group. These findings suggested lead-induced inhibition of growth plate development. The growth plate may be one of the key target tissues accounting for the adverse effects of chronic lead exposure on skeletal development.