Photobiomodulation therapy (PBMt) has been used to increase muscle performance and improve recovery when applied
before exercise. We aimed to evaluate the effects of PBMt using LASER on muscle oxygenation and performance. The
study was a randomized, participant and assessor-blinded, within-subject crossover trial with placebo control to test the
viability of the methods. Five physically active young women were randomly assigned to either placebo, or active PBMt
(12 diode cluster probe; 904 nm; 60 mW; 250 Hz; 43.2 J per site, 129.6 J total) in contact over rectus femoris (RF)
muscle of the dominant limb immediately before an isokinetic fatigue protocol. A one-week wash-out period preceded
cross-over. Electromyography and isokinetic performance measures were evaluated. Absolute concentrations of
deoxygenated haemoglobin and myoglobin (deoxy[Hb + Mb]) of the RF, an index of local microvascular fractional O2
extraction, was monitored continuously by near-infrared spectroscopy (NIRS). Total haemoglobin concentration as an
indicator of microvascular haematocrit was calculated as the sum of the deoxy[Hb + Mb] and oxy[Hb + Mb] signals.
PBMt pre-conditioning reduced time to peak torque when compared to placebo (P<0.05). PBMt resulted in a noticeably
reduced trend in deoxy[Hb + Mb] during exercise compared to placebo (P>0.05). PBMt before exercise improves
indicators of muscle performance, potentially by increasing local matching of bulk and microvascular O2 delivery
relative to skeletal muscle O2 utilisation. Further work is required to understand the effect of PBMt on haemodynamic
and metabolic characteristics of muscle.
We investigate the effects of a novel bioactive material (Biosilicate®) and low-level laser therapy (LLLT), at 60 J/cm2, on bone-fracture consolidation in osteoporotic rats. Forty female Wistar rats are submitted to the ovariectomy, to induce osteopenia. Eight weeks after the ovariectomy, the animals are randomly divided into four groups, with 10 animals each: bone defect control group; bone defect filled with Biosilicate group; bone defect irradiated with laser at 60 J/cm2 group; bone defect filled with Biosilicate and irradiated with LLLT, at 60 J/cm2 group. Laser irradiation is initiated immediately after surgery and performed every 48 h for 14 days. Histopathological analysis points out that bone defects are predominantly filled with the biomaterial in specimens treated with Biosilicate. In the 60-J/cm2 laser plus Biosilicate group, the biomaterial fills all bone defects, which also contained woven bone and granulation tissue. Also, the biomechanical properties are increased in the animals treated with Biosilicate associated to lasertherapy. Our results indicate that laser therapy improves bone repair process in contact with Biosilicate as a result of increasing bone formation as well as indentation biomechanical properties.
Muscle tissue is one of the most frequently affected by injury, whether during sports activities, or
work activities. In this context, biochemical and biophysical resources have been studied to minimize the
time of muscle regeneration. Among these, low intensity pulsed ultrasound (US) and low level laser
therapy (LLLT) may be highlighted. Despite a series of evidences about the positive effects of these
resources in the process of tissue regeneration, the cellular and morphological changes triggered by LLLT
and U.S. are still largely unknown. Thus, the aim of this study was to investigate the effects of US and
LLLT on muscle repair after cryolesion by means of histopathological analysis and immunohistochemistry
for COX-2. A total of thirty five male Wistar rats were randomly distributed into 4 groups: intact control group; injured control group: muscle injured animals without any treatment; laser treated group: muscle
injured animals treated with 830 nm laser and ultra-sound treated group: muscle injured animals treated
with US. The treatments started 24 hours post-surgery and were performed during 6 sessions. The animals
exposed to lasertherapy pointed out minor degenerative changes of muscle tissue. In the same way,
exposure to ultrasound was able to reduce tissue injuries induced by cryolesion, but less intense than laser
therapy. Strong COX-2 positive cells were found in rats submitted to cryolesion only, whereas COX-2
immunoexpression was lower in laser treated or ultrasound treated groups. In summary, this study reveals
that both lasertherapy and ultrasound have positive effects on muscle repair in rats.
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