The effects of low-level laser therapy on bone in diabetic and nondiabetic rats.
OBJECTIVE
The aim of the present study was to examine the effects of low-level laser therapy (LLLT) on the tibia of streptozotocin-induced diabetic (STZ-D) rats.


BACKGROUND
LLLT has been found to accelerate fracture healing in animals. Diabetes mellitus decreases bone volume and its biomechanical parameters.


METHODS
Twenty rats were divided randomly into four groups. Rats in the first two groups were administrated a single injection of STZ to induce diabetes, while animals in groups 3 and 4 were given a sham injection of distilled water. The right tibia in groups 1 and 2 was treated with a He-Ne laser (632.8 nm, 10 mW) of 28.6 and 382.2 J/cm(2), respectively. LLLT was performed daily for 14 consecutive days. The right tibia of rats in group 3 was treated with LLLT the same as group 2. The right tibia of rats in group 4 was used for based line studies. After 14 d, right tibiae and left tibiae (control bone) were extracted and subjected to the three-point bending test and histological study.


RESULTS
Maximum force (N) was significantly greater in laser-treated bones of groups 2 and 3 compared with their relevant control groups (paired Student t test, p = 0.05 and p = 0.007, respectively). Density of the bone lamella meshwork of compact bone in group 2 was significantly greater in comparison with its control group (paired Student t test, p = 0.005).


CONCLUSIONS
LLLT on tibia of STZ-D rats increased the bone lamella meshwork density of compact bone and also increased its strength.
Bayat
Mohammad
M
Cellular and Molecular Biology Research Center, Medical Faculty, Shahid Beheshti University, MC, Tehran, Iran. bayat_m@yahoo.com
Abdi
Shabnam
S
Javadieh
Farshad
F
Mohsenifar
Zhaleh
Z
Rashid
Masood Rafizadeh
MR
D000818:Animals; D015519:Bone Density / Q000528:radiation effects; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D004195:Disease Models, Animal; D017102:Fracture Healing / Q000528:radiation effects*; D054020:Lasers, Gas; D028022:Low-Level Light Therapy; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013977:Tibia / Q000528:radiation effects*; D013978:Tibial Fractures / Q000150:complications / Q000532:radiotherapy*