Efeitos do cloreto mercuroso sobre o desenvolvimento do tecido ósseo : propriedades físicas, químicas e biomecânicas do fêmur de ratos.

Abstract

Because of the lack of data about the mercury influence on bone metabolism it is important to investigate the bone parameters that can be affected by its effects. The aim of this study was to evaluate the physical and biomechanical bone alterations in adult rats contaminated with mercurous chloride during their development. The animals were separated in experimental and control groups: 9 male rats treated with saline 0.9% (0.1 ml/100g BW) and 16 male rats treated with mercurous chloride (1.25mg/kg BW) during 60 days, 5 days/week, by the stomacal gavage. After that, the animals were sacrificed and the right femur was dissected. The body weight, femoral length and thickness of femoral diaphysis were measured. The mechanical properties (maximum and failure forces, stiffness and yield) of femurs were evaluated by the tree-point bending test using the universal machine Instron model 4444. The bone volume was estimated by the Archimedes Principle. The wet and ash weight were also determined. The weight, length and major and minor diameters of the femurs were not different between the groups; however the length and the major diameter showed tendency to decrease. There was an increase (p=0,0460) of bone density of the contaminated animals. The mineral density and the mechanical properties were not different between the both groups. The dose of mercurous chloride used had little effect on bone development. It was observed a tendency of higher values of bone biomechanical properties and a decrease of the biometric values of the contaminated group. This would characterize a more resistant bone in spite of a lower mineral content.