Evaluation of the Effects of Photobiomodulation on Partial Osteotomy in Streptozotocin-Induced Diabetes in Rats.

OBJECTIVE: We examined the effects of photobiomodulation (PBM) on stereological parameters, and gene expression of Runt-related transcription factor 2 (RUNX2), osteocalcin, and receptor activator of nuclear factor kappa-B ligand (RANKL) in repairing tissue of tibial bone defect in streptozotocin (STZ)-induced type 1 diabetes mellitus (TIDM) in rats during catabolic response of fracture healing. BACKGROUND DATA: There were conflicting results regarding the efficacy of PBM on bone healing process in healthy and diabetic animals. MATERIALS AND METHODS: Forty-eight rats have been distributed into four groups: group 1 (healthy control, no TIDM and no PBM), group 2 (healthy test, no TIDM and PBM), group 3 (diabetic control, TIDM and no PBM), and group 4 (diabetic test, no TIDM and PBM). TIDM was induced in the groups 3 and 4. A partial bone defect in tibia was made in all groups. The bone defects of groups second and fourth were irradiated by a laser (890 nm, 80 Hz, 1.5 J/cm2). Thirty days after the surgery, all bone defects were extracted and were submitted to stereological examination and real-time polymerase chain reaction (RT-PCR). RESULTS: PBM significantly increased volumes of total callus, total bone, bone marrow, trabecular bone, and cortical bone, and the numbers of osteocytes and osteoblasts of callus in TIDM rats compared to those of callus in diabetic control. In addition, TIDM increased RUNX2, and osteocalcin in callus of tibial bone defect compared to healthy group. PBM significantly decreased osteocalcin gene expression in TIDM rats. CONCLUSIONS: PBM significantly increased many stereological parameters of bone repair in an STZ-induced TIDM during catabolic response of fracture healing. Further RT-PCR test demonstrated that bone repair was modulated in diabetic rats during catabolic response of fracture healing by significant increase in mRNA expression of RUNX2, and osteocalcin compared to healthy control rats. PBM also decreased osteocalcin mRNA expression in TIDM rats.

Effect of in vivo low-level laser therapy on bone marrow-derived mesenchymal stem cells in ovariectomy-induced osteoporosis of rats.

Postmenopausal osteoporosis (PMOP) is considered by decreased bone strength that escalates the threat of fractures. Positive effects of photobiomodulation (PBM) with pulse wave have been demonstrated in cell culture and animal models. The aim of this study was to assess the in vivo effects of PBM on viability and calcium ion release of ovariectomy induced osteoporosis (OVX) - bone marrow derived mesenchymal stem cells (BMMSCs). MATERIAL AND METHODS: 18 female rats were distributed into the following groups: 1) control healthy, 2) LASER-healthy (890nm, 80Hz, 1.5J/cm2, three days weekly, 60days), 3) control OVX, 4) LASER-OVX, 5) Alendronate (Alen.)-OVX [0.5mg/kg, 5days per week, 60days], and 6) Alen.+LASER-OVX. Ovariectomy was done on rats of groups 3, 4, 5 and 6. After that all rats were euthanized and their MSC harvested and cultured in complete osteogenic medium. In all groups, BMMSC viability, and calcium colorimetric assay were performed. RESULTS: We observed a significant increase in optical density (OD) of BMMSCs viability in LASER healthy group compared to control-OVX, Alen.-OVX, LASER-OVX, LASER+Alen.-OVX, groups. LASER+Alen.-OVX group displayed a significant escalation in OD of BMMSCs viability compared to LASER-OVX, Alen.-OVX, and control-OVX groups. There were a significant increase in calcium ion release of LASER-healthy group compared to control healthy, control-OVX, Alen.-OVX, LASER-OVX, and LASER+Alen.-OVX groups. LASER+Alen.-OVX group displayed a significant escalation in calcium ion release compared to LASER-OVX, Alen.-OVX, and control-OVX groups. CONCLUSION: Pulse wave (PW) PBM significantly stimulated viability and cell proliferation of healthy BMMSCs compared to those of control-OVX, OVX-alendronate, OVX-LASER, and LASER+alendronate-OVX. In addition stimulatory effect of LASER+alendronate on viability and cell proliferation of OVX-BMMSCs compared to those of control-OVX, alendronate-OVX, and LASER-OVX groups were found.

Evaluation of the Effects of Photobiomodulation on Biomechanical Properties and Hounsfield Unit of Partial Osteotomy Healing in an Experimental Rat Model of Type I Diabetes and Osteoporosis.

BACKGROUND: Pulsed wave (PW) lasers exhibit biostimulatory effects on fractures in healthy and diabetic animals. OBJECTIVE: This study aims to assess the effects of photobiomodulation on bone strength and Hounsfield unit (HU) for repair of a bone defect in an experimental rat model of type I diabetes mellitus (TIDM) and osteoporosis (OP). METHODS: We divided 30 female rats into six groups of n = 5 per group: (1) ovariectomy (OVX) control, (2) OVX + PW laser and no TIDM, (3) OVX control + TIDM, (4) OVX + TIDM + PW laser, (5) OVX + TIDM + alendronate, and (6) OVX + TIDM + PW laser + alendronate. TIDM was induced in rats by streptozotocin (STZ). A partial osteotomy was made in the right tibia of each rat. We used an infrared laser (890 nm, 80 Hz, 1.5 J/cm2) 3 times per week. At 30 days after surgery, the callus areas within the rats' tibias were submitted to computed tomography scanning followed by the three-point bending test. RESULTS: The PW laser + alendronate group had significantly increased HU and biomechanical properties of repairing bone defect in STZ + OVX rats compared with the control groups. CONCLUSIONS: Combined treatment of PW laser and alendronate significantly enhanced bone repair in an experimental model rat of TIDM and OP.

Evaluation of the Effects of Photobiomodulation on Bone Healing in Healthy and Streptozotocin-Induced Diabetes in Rats.

OBJECTIVE: This study aimed to assess the effects of Photobiomodulation (PBM) with pulsed wave laser on Hounsfield unit (HU) and bone strength at a catabolic response (bone resorption) of a callus bone defect in healthy and streptozotocin (STZ)- induced type I diabetes mellitus (TI DM) in rats. BACKGROUND DATA: Conflicting results exist regarding the effect of PBM on bone healing in healthy and diabetic animals. MATERIALS AND METHODS: We randomly divided 20 adult female rats into the following groups: (1) control, no TI DM, and no PBM; (2) no TI DM and PBM; (3) TI DM and no PBM; and (4) TI DM and PBM. TI DM was induced by STZ. All rats underwent partial transversal standardized osteotomies in their right tibias. The rats received PBM (890 nm, 80 Hz, 1.5 J/cm2) thrice per week during 30 days. At 4 weeks after the surgery, the rats were sacrificed and their tibias submitted to computed tomography scanning to measure HU. The samples underwent a three-point bending test to evaluate bone strength. RESULTS: Analysis of variance (ANOVA) (p = 0.013) results showed that treatment by PBM significantly increased the biomechanical property (stress high load) of the callus defect from the partial tibia osteotomy in healthy rats compared to the control groups. However, we observed no significant increase in the biomechanical properties of the laser-treated diabetic bone defect compared to the control diabetic group. The ANOVA for the HU of callus density produced a p value of 0.000. A significant increase existed in the mean callus density in the healthy groups compared to the diabetic groups. CONCLUSIONS: The 80-Hz laser did not significantly enhance bone repair from an osteotomy of the tibia in an experimental model of TI DM rats.

The effect of combined photobiomodulation and metformin on open skin wound healing in a non-genetic model of type II diabetes.

This study intended to examine the combined influences of photobiomodulation (PBM) and metformin on the microbial flora and biomechanical parameters of wounds in a non-genetic model of type II diabetes mellitus (TII DM). We induced a non-genetic model of TII DM in 20 rats by feeding them a 10% fructose solution for 2weeks followed by an injection of streptozotocin (STZ, 40mg/kg). After 21days from the injection of STZ, we induced one full-thickness skin wound in each of the diabetic rats. We randomly divided the rats into four groups: i) placebo; ii) pulsed wave laser (890nm, 80Hz, 0.324J/cm2); iii) metformin; and iv) laser+metformin. Rats received daily intraperitoneal injections of metformin (50mg/kg). On days 7and 15 we inspected the microbial flora of each wound. On day 15 we obtained a standard sample from each healing wound for biomechanical analyses. PBM significantly decreased colony-forming units (CFUs) 7days after wound infliction compared to the placebo group (LSD test, p=0.012). Metformin significantly enhanced the biomechanical property (stress high load) of the wounds compared to the placebo group (LSD test, p=0.028). We observed the same significant result for PBM compared to the placebo group (LSD test, p=0.047). PBM significantly accelerated the wound healing process and significantly reduced CFUs of bacteria in a non-genetic rat model of TII DM.

The Effect of Combined Pulsed Wave Low-Level Laser Therapy and Human Bone Marrow Mesenchymal Stem Cell-Conditioned Medium on Open Skin Wound Healing in Diabetic Rats.

OBJECTIVE: The nobility of this scientific study was to investigate the combined effects of pulsed wave low-level laser therapy (PWLLLT) and human bone marrow mesenchymal stem cell-conditioned medium (hBM-MSC-CM) on the biomechanical parameters of wounds in an experimental model for diabetes mellitus (DM). BACKGROUND DATA: PWLLLT exhibited biostimulatory effects on wounds in diabetic animals. Secretomes can be administered into wounds by the use of BM-MSC-CM. MATERIALS AND METHODS: Type I DM was induced in rats by streptozotocin (STZ). Two wounds were made on proximal and distal parts in the dorsal region of each rat. Rats were divided into four groups. The first group was considered as the control group. The second group received hBM-MSC-CM. The third group received PWLLLT. The fourth group received hBM-MSC-CM+LASER. hBM-MSC-CM was administrated twice intraperitoneally. The proximal wounds in the third and fourth groups were treated with a pulsed laser by 890 nm wavelength, 80 Hz frequency, and 0.2 J/cm(2) energy densities. On the 15th day, a standard sample from each healing wound was submitted for biomechanical examination. The data were analyzed by analysis of variance test. RESULTS: PWLLLT and hBM-MSC-CM, alone or in combination, significantly increased biomechanical parameters within the healing wounds. However, PWLLLT was statistically more effective compared with the hBM-MSC-CM. In the third and fourth groups, the numbers of wound closures were significantly enhanced in proximal part, contrary to the control ones. CONCLUSIONS: It was magnificently attained that PWLLLT significantly accelerated the wound healing process in the experimental model for STZ-induced type I DM rats.