Comparison of the Effects of Electrical Field Stimulation and Low-Level Laser Therapy on Bone Loss in Spinal Cord-Injured Rats

Objective: This study investigated the effects of low-level laser therapy (LLLT) and electrical stimulation (ES) on bone loss in spinal cord-injured rats. Materials and Methods: Thirty-seven male Wistar rats were divided into four groups: standard control group (CG); spinal cord-injured control (SC); spinal cord-injured treated with laser (SCL; GaAlAs, 830 nm, CW, 30mW/cm, 250 J/cm(2)); and spinal cord-injured treated with electrical field stimulation (SCE; 1.5 MHz, 1: 4 duty cycles, 30 mW, 20 min). Biomechanical, densitometric, and morphometric analyses were performed. Results: SC rats showed a significant decrease in bone mass, biomechanical properties, and morphometric parameters (versus CG). SCE rats showed significantly higher values of inner diameter and internal and external areas of tibia diaphyses; and the SCL group showed a trend toward the same result (versus SC). No increase was found in either mechanical or densitometric parameters. Conclusion: We conclude that the mentioned treatments were able to initiate a positive bone-tissue response, maybe through stimulation of osteoblasts, which was able to determine the observed morphometric modifications. However, the evoked tissue response could not determine either biomechanical or densitometric modifications.Universidade Federal de São Paulo UNIFESP, Dept Biosci, Santos, SP, BrazilUniv Fed Sao Carlos UFSCar, Dept Physiotherapy, Sao Carlos, SP, BrazilUniv São Paulo, Sch Med, Div Rheumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiotherapy, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Med, Div Endocrinol, São Paulo, BrazilUniv São Paulo, Bioengn Div, Sao Carlos, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Biosci, Santos, SP, BrazilUniversidade Federal de São Paulo, Dept Physiotherapy, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Med, Div Endocrinol, São Paulo, BrazilWeb of Scienc