Low-level laser therapy associated to a resistance training protocol on bone tissue in diabetic rats.
OBJECTIVE
The present study aimed to evaluate the in vivo response of a resistance training and low-level laser therapy (LLLT) on tibias and femurs of rats with diabetes mellitus (DM).


METHODS
Forty male Wistar rats were randomly distributed into four experimental groups: control group (CG), diabetic group (DG), diabetic trained group (TG) and diabetic trained and laser irradiated group (TLG). DM was induced by streptozotocin (STZ) and after two weeks laser and resistance training started, performed for 24 sessions, during eight weeks. At the end of the experiment, animals were euthanized and tibias and femurs were removed for analysis. Histological, histomorphometrical, immunohistochemistry and mechanical analyses were performed.


RESULTS
Trained groups, with or without laser irradiation, showed increased cortical area, bone density and biomechanical properties. The immunohistochemical analysis revealed that TG and TLG demonstrated an increased RUNX2 expression. RANK-L immunoexpression was similar for all experimental groups.


CONCLUSIONS
In conclusion, it can be suggested that the resistance exercise program stimulated bone metabolism, culminating in increased cortical tibial area, bone mineral content, bone mineral density and biomechanical properties. Furthermore, the association of physical exercises and LLLT produced higher values for bone mineral content and stiffness. Consequently, these data highlight the potential of physical exercise in the management of bone loss due to DM and the possible extra osteogenic stimulus offered by lasertherapy. Further long-term studies should be carried out to provide additional information.
Departamento de Biotecnologia, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brasil.
Tatiane Lopes
TL
Patrocínio-Silva
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
André Moreira Fogaça de
AM
Souza
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Raul Loppi
RL
Goulart
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Carolina Fuirini
CF
Pegorari
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Jussan Rodrigues
JR
Oliveira
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Kelly Rossetti
KR
Fernandes
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Angela Maria Paiva
AM
Magri
Departamento de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brasil.
Rosa Maria Rodrigues
RM
Pereira
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Daniel Araki
DA
Ribeiro
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Márcia Regina
MR
Nagaoka
Departamento de Biociências, Universidade Federal de São Paulo (Unifesp), Santos, SP, Brasil.
Ana Claudia Muniz
AC
Rennó
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D015519:Bone Density / Q000502:physiology / Q000528:radiation effects; D001851:Bone Diseases, Metabolic / Q000503:physiopathology / Q000517:prevention & control; D003720:Densitometry / Q000379:methods; D003920:Diabetes Mellitus / Q000503:physiopathology* / Q000517:prevention & control; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology / Q000517:prevention & control; D005269:Femur / Q000502:physiology* / Q000528:radiation effects*; D007150:Immunohistochemistry; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D053245:RANK Ligand / Q000032:analysis; D011897:Random Allocation; D017208:Rats, Wistar; D012016:Reference Values; D015203:Reproducibility of Results; D055070:Resistance Training / Q000379:methods*; D013311:Streptozocin; D013977:Tibia / Q000502:physiology* / Q000528:radiation effects*; D013997:Time Factors; D016896:Treatment Outcome
D001786:Blood Glucose; D053245:RANK Ligand; D013311:Streptozocin