Lycium barbarum polysaccharide fraction associated with photobiomodulation protects from epithelium thickness and collagen fragmentation in a model of cutaneous photodamage

Lasers in Medical Science - Ultraviolet radiation (UVR) is the major etiologic agent of cutaneous photoaging, and different strategies are used to prevent and treat this condition. The...     

The effects of low-level laser irradiation on bone tissue in diabetic rats

Diabetes mellitus (DM) leads to a decrease in bone mass and increase the risk of osteoporosis and in this context, many treatments have shown to accelerate bone metabolism. It seems that low-level laser therapy (LLLT) is able of stimulating osteoblast activity and produced increased biomechanical properties. However, its effects on bone in diabetic rats are not fully elucidated. The aim of this study was to evaluate the effects of LLLT on bone formation, immunoexpression of osteogenic factors, biomechanical properties and densitometric parameters in diabetic rats. Thirty male Wistar rats were randomly distributed into three experimental groups: control group, diabetic group, and laser-treated diabetic group. DM was induced by streptozotocin (STZ) and after 1 week laser treatment started. An 830-nm laser was used, performed for 18 sessions, during 6 weeks. At the end of the experiment, animals were euthanized and tibias and femurs were defleshed for analysis. Extensive resorptive areas as a result of osteoclasts activity were noticed in DG when compared to control. Laser-treated animals showed an increased cortical area. The immunohistochemical analysis revealed that LLLT produced an increased RUNX-2 expression compared to other groups. Similar RANK-L immunoexpression was observed for all experimental groups. In addition, laser irradiation produced a statistically increase in fracture force, bone mineral content (BMC) and bone mineral density compared to DG. The results of this study indicate that the STZ model was efficient in inducing DM 1 and producing a decrease in cortical diameter, biomechanical properties and in densitometric variables. In addition, it seems that LLLT stimulated bone metabolism, decreased resorptive areas, increased RUNX-2 expression, cortical area, fracture force, BMD, and BMC. Further studies should be developed to provide additional information concerning the mechanisms of action of laser therapy in diabetic bone in experimental and clinical trials.     

Low level laser therapy (830nm) improves bone repair in osteoporotic rats: similar outcomes at two different dosages

Background and objective

The goal of this study was to investigate the effects of low level laser therapy (LLLT) in osteoporotic rats by means of subjective histopathological analysis, deposition of collagen at the site of fracture, biomechanical properties and immunohistochemistry for COX-2, Cbfa-1 and VEGF.

Material and methods

A total of 30 female Wistar rats (12 weeks-old, ± 250 g) were submitted to ovariectomy (OVX). Eight weeks after the OVX, a tibial bone defect was created in all animals and they were randomly divided into 3 groups (n = 10): control bone defect group (CG): bone defects without any treatment; laser 60 J/cm² group (L60): animals irradiated with LLLT, at 60 J/cm² and laser 120 J/cm² group (L120): animals irradiated with LLLT, at 120 J/cm².

Results

In the laser treated groups, at both fluences, a higher amount of newly formed bone was evidenced as well as granulation tissue compared to control. Picrosirius analysis demonstrated that irradiated animals presented a higher deposition of collagen fibers and a better organization of these fibers when compared to other groups, mainly at 120 J/cm². COX-2, Cbfa-1 or VEGF immunoreactivity was detected in a similar manner either 60 J/cm² or 120 J/cm² fluences. However, no differences were shown in the biomechanical analysis.

Conclusion

Taken together, our results support the notion that LLLT improves bone repair in the tibia of osteoporotic rats as a result of stimulation of the newly formed bone, fibrovascularization and angiogenesis.     

Subarachnoid hemorrhage and COVID-19: Association or coincidence?

Some evidences suggest the involvement of the central nervous system in patients infected with SARS-CoV-2. We aim to analyze possible associations between coronavirus disease 2019 (COVID-19) pandemic and spontaneous subarachnoid hemorrhage (SAH), in a comprehensive neurological center.We conducted a retrospective case series of 4 patients infected by COVID-19, who developed spontaneous SAH. Clinical data were extracted from electronic medical records.Between March 24, 2020, and May 22, 2020, 4 cases (3 females; 1 male) of SAH were identified in patients infected with SARS-CoV-2, in a comprehensive neurological center in Brazil. The median age was 55.25 years (range 36 -71). COVID-19-related pneumonia was severe in 3 out of 4 cases, and all patients required critical care support during hospitalization. The patients developed Fisher grade III and IV SAH. Digital subtraction angiography (DSA) was performed in 3 of the 4 patients. However, in only 1 case, an aneurysm was identified. Inflammatory blood tests were elevated in all cases, with an average D-dimer of 2336 μg/L and mean C-reactive protein (CRP) of 3835 mg/dl The outcome was poor in the majority of the patients, with 1 death (25%); 2 (50%) remained severely neurologically affected (mRS:4); and 1 (25%) had slight disability (mRS:2).This study shows a series of 4 rare cases of SHA associated with COVID-19. The possible mechanisms underlying the involvement of SARSCoV-2 and SHA is yet to be fully understood. Therefore, SHA should be included in severe neurological manifestations in patients infected by this virus.     

Photobiomodulation increases mitochondrial citrate synthase activity in rats submitted to aerobic training

This study investigated the effects of photobiomodulation by low-laser laser therapy (LLLT) on the activities of citrate synthase (CS) and lactate dehydrogenase (LDH) and the anaerobic threshold (AT) in rats submitted to treadmill exercise. Fifty-four rats were allocated into four groups: rest control (RCG), rest laser (RLG), exercise control (ECG), and exercise laser (ELG). The infrared LLLT was applied daily on the quadriceps, gluteus maximum, soleus, and tibialis anterior muscles. Muscle samples (soleus, tibialis anterior, and cardiac muscles) were removed 48 h after the last exercise session for spectrophotometric analysis of the CS and LDH. The CS activity (μmol/protein) in ELG (16.02 and 0.49) was significantly greater (P?<?0.05) than RCG (2.34 and 0.24), RLG (6.25 and 0.17), and ECG (6.76 and 0.26) in the cardiac and soleus muscles, respectively. The LDH activity (in 1 Mm/protein) in soleus muscle was smaller (P?<?0.05) for ELG (0.33) compared to ECG (0.97), RLG (0.79), and RCG (1.07). For cardiac muscle, the LDH activity was smaller (P?<?0.05) in ELG (1.38) compared to ECG (1.91) and RCG (2.55). The ECG and ELG showed increases in the maximum speed and a shift of the AT to higher effort levels after the training period, but no differences occurred between the exercised groups. In conclusion, the aerobic treadmill training combined with LLLT promotes an increase of oxidative capacity in this rat model, mainly in muscles with greater aerobic capacity.