Tissue and biomechanical analysis of osteopenics bones: experimental study in spinal cord injured rats

Abstract

Spinal cord is a chronic affliction, with high incidence, that causes permanent and irreversible functional consequences in patients. This disease has many complications that reduces life quality and increases morbidly and mortality. The complications affect many organs and systems, as muscle-skeletal system. Osteopenia and osteoporosis are skeletal complications, but its physiopathology is not completely elucidated. Professional use prophylactic techniques to reduce bone mass loss and avoid fractures that may lead patient to death. Physiotherapist with this purpose applies weight bearing and electrical stimulation. However, clinical studies show controversial results related to prophylactic effects of them. So, the purpose of the current study will be to evaluate changes in bones (humeral, L4, L5, femur and tibia) in spinal cord injured rats and, to verify influence of physiotherapeutic techniques (weight bearing and electrical stimulation) in these bone structures, comparing these applications in acute and chronic phase. We will use 100 rats (270-280g), divided into 5 groups (n=20 per group): (1) Sham, (2) SC, spinal cord without treatment, (3) SC-WB, spinal cord with weight bearing as treatment, (4) SC-ES, spinal cord with electrical stimulation as treatment and (5) SC-WB+ES, spinal cord with weight bearing and electrical stimulation as treatment. Groups were divided into 2 subgroups (n=10): A and B. Subgroups A will be killed 35 days after surgery and, those with treatment will start it 3 days post-lesion (acute phase) and subgroups B will be killed 62 days after surgery and, those underwent to treatment will start it 30 days post-lesion (chronic phase). Bones will be submitted to biochemical, densitometric, macroscopic, mechanical and microscopic (histomorphometry by light and electronic microscope). (AU)