An evaluation of the effect of pulsed wave low-level laser therapy on the biomechanical properties of the vertebral body in two experimental osteoporosis rat models.

Osteoporosis (OP) increases vertebral fragility as a result of the biomechanical effects of diminished bone structure and composition. This study has aimed to assess the effects of pulsed wave low-level laser therapy (PW LLLT) on cancellous bone strength of an ovariectomized (OVX-d) experimental rat model and a glucocorticoid-induced OP (GIOP) experimental rat model. There were four OVX-d groups and four dexamethasone-treated groups. A group of healthy rats was used for baseline evaluations. The OVX-d rats were further subdivided into the following groups: control rats with OP, OVX-d rats that received alendronate, OVX-d rats treated with PW LLLT, and OVX-d rats treated with alendronate and PW LLLT. The remaining rats received dexamethasone and were divided into four groups: control, alendronate-treated rats, laser-treated rats, and laser-treated rats with concomitant administration of alendronate. PW LLLT (890 nm, 80 Hz, 0.972 J/cm(2)) was performed on the spinal processes of the T12, L1, L2, and L3 vertebras. We extracted the L1 vertebrae and submitted them to a mechanical compression test. Biomechanical test findings showed positive effects of the PW LLLT and alendronate administration on increasing bending stiffness and maximum force of the osteoporotic bones compared to the healthy group. However, laser treatment of OVA-d rats significantly increased stress high load compared to OVA-d control rats. PW LLLT preserved the cancellous (trabecular) bone of vertebra against the detrimental effects of OV-induced OP on bone strength in rats compared to control OV rats.

Effects of pentoxifylline administration on histomorphological parameters of streptozotocin-induced diabetic rat testes.

The effect of pentoxifylline (PTX) administration on histomorphological parameters of streptozotocin (STZ)-induced type 1 diabetes mellitus (DM) in male rat testes were evaluated. We randomly divided 40 male rats into the following four groups: group 1: control or normal glycemic (NG) rats; group 2 or NG rats that received only normal saline (NS), (NG+NS); group 3 or diabetic rats which were not treated by PTX (DM+vehicle solution (NS)); and group 4 which comprised diabetic rats treated with 50 mg/kg of PTX (DM+PTX). Type 1 DM was induced by intraperitoneal injection of STZ (55 mg/kg). Rats were held for 30 days after which the experimental group received PTX twice daily (25 mg/kg) or NS. After 14 days of treatment by PTX or NS, the left testes from all rats were extracted and prpared for histological study. Apoptotic cells, blood vessel density, and spermatogenesis were evaluated. Data were analyzed by ANOVA test. PTX-treated-diabetic rats showed a significant decrease in number of apoptotic cells and decrease in blood vessel density compared to the DM+NS rats. A significant increase in spermatogenesis was observed in the PTX-treated diabetic group, compared to the DM+NS groups. It was concluded that PTX administration to STZ-induced type 1 DM rats affected apoptotic cell number positively. Moreover, blood vessel density significantly decreased and improvements were observed in spermatogenesis.

Supraphysiologic glucocorticoid administration increased biomechanical bone strength of rats' vertebral body.

The aim of this study is to assess the effects of different glucocorticoid administration protocols on biomechanical properties of the first lumbar vertebral body in rats. We divided 40 male rats into the following groups: control, dexamethasone (7 mg/week), dexamethasone (0.7 mg/week), methylprednisolone (7 mg/kg/week), methylprednisolone (5 mg/kg twice weekly), dexamethasone (7 mg/kg three times per week), dexamethasone (0.7 mg/kg three times per week, and low-level laser treated rats. Lumbar vertebrae in rats were exposed to the pulsed laser. We conducted a biomechanical test to examine the mechanical properties of vertebral body in rats' lumbar bone. Supraphysiologic glucocorticoid administration protocols did not impair the biomechanical properties of rats' vertebral bodies compared to control and laser-treated rats. Supraphysiologic glucocorticoid administration caused an anabolic effect on the vertebral bodies.