Visible 532 nm laser irradiation of human adipose tissue-derived stem cells: effect on proliferation rates, mitochondria membrane potential and autofluorescence

Photobiomodulation: a novel approach to promote trans-differentiation of adipose-derived stem cells into neuronal-like cells

JOURNAL/nrgr/04.03/01300535-202502000-00035/figure1/v/2024-05-28T214302Z/r/image-tiff Photobiomodulation, originally used red and near-infrared lasers, can alter cellular metabolism. It has been demonstrated that the visible spectrum at 451-540 nm does not necessarily increase cell proliferation, near-infrared light promotes adipose stem cell proliferation and affects adipose stem cell migration, which is necessary for the cells homing to the site of injury. In this in vitro study, we explored the potential of adipose-derived stem cells to differentiate into neurons for future translational regenerative treatments in neurodegenerative disorders and brain injuries. We investigated the effects of various biological and chemical inducers on trans-differentiation and evaluated the impact of photobiomodulation using 825 nm near-infrared and 525 nm green laser light at 5 J/cm2. As adipose-derived stem cells can be used in autologous grafting and photobiomodulation has been shown to have biostimulatory effects. Our findings reveal that adipose-derived stem cells can indeed trans-differentiate into neuronal cells when exposed to inducers, with pre-induced cells exhibiting higher rates of proliferation and trans-differentiation compared with the control group. Interestingly, green laser light stimulation led to notable morphological changes indicative of enhanced trans-differentiation, while near-infrared photobiomodulation notably increased the expression of neuronal markers. Through biochemical analysis and enzyme-linked immunosorbent assays, we observed marked improvements in viability, proliferation, membrane permeability, and mitochondrial membrane potential, as well as increased protein levels of neuron-specific enolase and ciliary neurotrophic factor. Overall, our results demonstrate the efficacy of photobiomodulation in enhancing the trans-differentiation ability of adipose-derived stem cells, offering promising prospects for their use in regenerative medicine for neurodegenerative disorders and brain injuries.

Assessing the Impact of High Photon Energy Wavelengths on the Treatment of Chronic Neck and Shoulder Pain

The effect of low-level laser therapy with high photon energy wavelengths, green and violet, for treating chronic musculoskeletal pain was examined in the first-ever clinical trial of its kind. Participants (n = 43) underwent a single 13-minute laser session. The primary measure of effectiveness was the change in initial visual analog pain (VAS) scores observed three minutes posttreatment. The success of a participant was defined in advance as a reduction of ≥30% in VAS scores, while the success of the study was predetermined as achieving a 65 ± 5% success rate among individual participants. Results demonstrated subjects' VAS pain scores decreased from 71.79 to 34.02 (p < 0.0001), while most participants in the study (81.4%) achieved a ≥30% decrease in pain scores. The findings from this clinical investigation provided substantial support for the first Food and Drug Administration clearance (K221987) for the combined application of green and violet lasers.

Enhancing therapeutic efficacy of human adipose-derived stem cells by modulating photoreceptor expression for advanced wound healing

Background

Human adipose-derived stem cells (hADSCs) have been widely used for regenerative medicine because of their therapeutic efficacy and differentiation capacity. However, there are still limitations to use them intactly due to some difficulties such as poor cell engraftment and viability after cell transplantation. Therefore, techniques such as photobiomodulation (PBM) are required to overcome these limitations. This study probed improved preclinical efficacy of irradiated hADSCs and its underlying molecular mechanism.

Methods

hADSCs were irradiated with green organic light-emitting diodes (OLEDs). Treated cells were analyzed for mechanism identification and tissue regeneration ability verification. Expression levels of genes and proteins associated with photoreceptor, cell proliferation, migration, adhesion, and wound healing were evaluated by performing multiple assays and immunostaining. Excision wound models were employed to test in vivo therapeutic effects.

Results

In vitro assessments showed that Opsin3 (OPN3) and OPN4 are both expressed in hADSCs. However, only OPN4 was stimulated by green OLED irradiation. Cell proliferation, migration, adhesion, and growth factor expression in treated hADSCs were enhanced compared to control group. Conditioned medium containing paracrine factors secreted from irradiated hADSCs increased proliferation of human dermal fibroblasts and normal human epidermal keratinocytes. Irradiated hADSCs exerted better wound healing efficacy in vivo than hADSCs without OLED irradiation.

Conclusions

Our study introduces an intracellular mechanism of PBM in hADSCs. Our results revealed that photoreceptor OPN4 known to activate G_q-protein and consequently lead to reactive oxygen species production responded to OLED irradiation with a wavelength peak of 532 nm. In conclusion, green OLED irradiation can promote wound healing capability of hADSCs, suggesting that green OLED has potential preclinical applications.

Single and consecutive application of near-infrared and green irradiation modulates adipose derived stem cell proliferation and affect differentiation factors

Regenerative medicine uses undifferentiated adipose-derived mesenchymal stem cells (ADMSCs) to differentiate into multiple cell types. Photobiomodulation (PBM) is a rapidly growing treatment for pain and inflammation reduction, as well as tissue healing. PBM's efficacy is dependent on wavelength and energy dosage. Red (600-700 nm) and near-infrared (780-1100 nm) wavelengths have been shown to promote cell proliferation. Light wavelengths such as green (495 nm-570 nm) have been found to influence ADMSC differentiation. The initiation of ADMSC proliferation and differentiation requires physiologically relevant levels of reactive oxygen species (ROS), while increased levels inhibit self-renewal. Stem cell differentiation is guided by mitochondrial metabolism, where an increased mitochondrial membrane potential (MMP) is associated with higher in vitro differentiation capacity. ADMSCs must home to and accumulate at the sites of injury in regenerative medicine, so cell homing is critical. The aim of this in vitro study was to compare consecutive NIR (825 nm) and green (525 nm) applications on ADMSC morphology and physiology with the possibility that multiple wavelengths could lead to a combination of the two effects. The results showed that concurrent use of NIR-green irradiation significantly stimulated ADMSC proliferation, increasing population density and cellular ATP. Furthermore, NIR-green showed a time dependent increase in ROS production and was significantly higher at 7 days. Consecutive NIR-green irradiation significantly increased MMP and was most effective at facilitating ADMSC migration over time. Findings suggest that with consecutive NIR and green irradiation, the ADMSCs can rapidly proliferate, but can also be modulated for regenerative purposes.

Biological Responses of Stem Cells to Photobiomodulation Therapy

BACKGROUND

Stem cells have attracted the researchers interest, due to their applications in regenerative medicine. Their self-renewal capacity for multipotent differentiation, and immunomodulatory properties make them unique to significantly contribute to tissue repair and regeneration applications. Recently, stem cells have shown increased proliferation when irradiated with low-level laser therapy or Photobiomodulation Therapy (PBMT), which induces the activation of intracellular and extracellular chromophores and the initiation of cellular signaling. The purpose of this study was to evaluate this phenomenon in the literature.

METHODS

The literature investigated the articles written in English in four electronic databases of PubMed, Scopus, Google Scholar and Cochrane up to April 2019. Stem cell was searched by combining the search keyword of "low-level laser therapy" OR "low power laser therapy" OR "low-intensity laser therapy" OR "photobiomodulation therapy" OR "photo biostimulation therapy" OR "LED". In total, 46 articles were eligible for evaluation.

RESULTS

Studies demonstrated that red to near-infrared light is absorbed by the mitochondrial respiratory chain. Mitochondria are significant sources of reactive oxygen species (ROS). Mitochondria play an important role in metabolism, energy generation, and are also involved in mediating the effects induced by PBMT. PBMT may result in the increased production of (ROS), nitric oxide (NO), adenosine triphosphate (ATP), and cyclic adenosine monophosphate (cAMP). These changes, in turn, initiate cell proliferation and induce the signal cascade effect.

CONCLUSION

The findings of this review suggest that PBMT-based regenerative medicine could be a useful tool for future advances in tissue engineering and cell therapy.

Phenotypical Characterization and Neurogenic Differentiation of Rabbit Adipose Tissue-Derived Mesenchymal Stem Cells

Although the rabbit is a frequently used biological model, the phenotype of rabbit adipose-derived mesenchymal stem cells (rAT-MSCs) is not well characterized. One of the reasons is the absence of specific anti-rabbit antibodies. The study aimed to characterize rAT-MSCs using flow cytometry and PCR methods, especially digital droplet PCR, which confirmed the expression of selected markers at the mRNA level. A combination of these methods validated the expression of MSCs markers (CD29, CD44, CD73, CD90 and CD105). In addition, cells were also positive for CD49f, vimentin, desmin, α-SMA, ALDH and also for the pluripotent markers: NANOG, OCT4 and SOX2. Moreover, the present study proved the ability of rAT-MSCs to differentiate into a neurogenic lineage based on the confirmed expression of neuronal markers ENO2 and MAP2. Obtained results suggest that rAT-MSCs have, despite the slight differences in marker expression, the similar phenotype as human AT-MSCs and possess the neurodifferentiation ability. Accordingly, rAT-MSCs should be subjected to further studies with potential application in veterinary medicine but also, in case of their cryopreservation, as a source of genetic information of endangered species stored in the gene bank.

[Current review of factors in the stem cell donor that influence the regenerative potential of adipose tissue-derived stem cells]

BACKGROUND

Regenerative therapies like cell-assisted lipotransfer or preclinical experimental studies use adipose tissue-derived stem cells (ASCs) as the main therapeutic agent. But there are also factors depending on the clinical donor that influence the cell yield and regenerative potential of human ASCs and stromal vascular fraction (SVF). Therefore, the aim of this review was to identify and evaluate these factors according to current literature.

METHODS

For this purpose, a systematic literature review was performed with focus on factors affecting the regenerative potential of ASCs and SVF using the National Library of Medicine.

RESULTS

Currently, there is an abundance of studies regarding clinical donor factors influencing ASCs properties. But there is some contradiction and need for further investigation. Nevertheless, we identified several recurrent factors: age, sex, weight, diabetes, lipoedema, use of antidepressants, anti-hormonal therapy and chemotherapy.

CONCLUSION

We recommend characterisation of the ASC donor cohort in all publications, regardless of whether they are experimental studies or clinical trials. By these means, donor factors that influence experimental or clinical findings can be made transparent and results are more comparable. Moreover, this knowledge can be used for study design to form a homogenous donor cohort by precise clinical history and physical examination.

In Vitro Cytological Responses against Laser Photobiomodulation for Periodontal Regeneration

Periodontal disease is a chronic inflammatory disease caused by periodontal bacteria. Recently, periodontal phototherapy, treatment using various types of lasers, has attracted attention. Photobiomodulation, the biological effect of low-power laser irradiation, has been widely studied. Although many types of lasers are applied in periodontal phototherapy, molecular biological effects of laser irradiation on cells in periodontal tissues are unclear. Here, we have summarized the molecular biological effects of diode, Nd:YAG, Er:YAG, Er,Cr:YSGG, and CO₂ lasers irradiation on cells in periodontal tissues. Photobiomodulation by laser irradiation enhanced cell proliferation and calcification in osteoblasts with altering gene expression. Positive effects were observed in fibroblasts on the proliferation, migration, and secretion of chemokines/cytokines. Laser irradiation suppressed gene expression related to inflammation in osteoblasts, fibroblasts, human periodontal ligament cells (hPDLCs), and endothelial cells. Furthermore, recent studies have revealed that laser irradiation affects cell differentiation in hPDLCs and stem cells. Additionally, some studies have also investigated the effects of laser irradiation on endothelial cells, cementoblasts, epithelial cells, osteoclasts, and osteocytes. The appropriate irradiation power was different for each laser apparatus and targeted cells. Thus, through this review, we tried to shed light on basic research that would ultimately lead to clinical application of periodontal phototherapy in the future.

Biostimulative effect of laser on growth of mesenchymal stem/stromal cells in vitro

Introduction

Human adipose tissue-derived mesenchymal stem/stromal cells (hAT-MSCs) are multipotent stromal cells with a high potential application in tissue engineering and regenerative medicine. Laser irradiation of the place where the cells were implanted can stimulate their proliferation, increase the secretion of growth factors and thus increase the therapeutic effect.

Aim

To evaluate the influence of two lasers: Er:YAG and diode on the growth of hAT-MSCs in vitro.

Material and methods

hAT-MSCs were isolated from human subcutaneous adipose tissue. Immunophenotype of hAT-MSCs was confirmed by flow cytometry. Multipotency of hAT-MSCs was confirmed by differentiation into adipogenic, osteogenic and chondrogenic lineages. hAT-MSCs were irradiated with Er:YAG laser (wavelength 2940 nm, frequency 5, 10 Hz, doses: 0.1–1.2 J/cm²) for 2 s and 4 s and diode laser (wavelength 635 nm and doses: 1–8 J/cm²) for 5, 10, 20, 30 and 40 s. Cell viability was analysed 24 h after the exposure using MTT assay.

Results

Growth stimulation of hAT-MSCs after 5 Hz Er:YAG laser exposure, 0.1 J/cm² dose for 4 s and 0.3 J/cm² dose for 4 s was shown in comparison with the control group. Significant growth stimulation of hAT-MSCs after diode laser irradiation in doses of 1–4 J/cm² was demonstrated compared to the control group.

Conclusions

The presented results indicate that both lasers, Er:YAG and diode can be used to stimulate stem/stromal cell growth in vitro. The biostimulative effect of laser therapy on stromal cells may be used in the future in aesthetic dermatology in combined laser and cell therapy.

Cytotoxicity studies of an optoacoustic stimulation strategy for the development of laser-based hearing aids

SIGNIFICANCE

Worldwide, ∼460  million people suffer from disabling hearing impairment. Many of these patients are still not sufficiently supplied with currently available auditory technologies. Optical stimulation of the hearing organ offers a promising alternative for a new generation of auditory prostheses.

AIM

To assess the biocompatibility margins of our laser pulse amplitude strategy in vitro, we designed a protocol and present the effects on normal human dermal fibroblasts, human chondrocytes, and human osteoblasts.

APPROACH

Laser pulses of 532 nm were applied over 120 s using our laser pulse amplitude modulation strategy. We then assessed cell viability and cytotoxicity through fluorescence staining and quantitative polymerase chain reaction-analysis regarding 84 key player-genes for cytotoxicity and stress response.

RESULTS

The first in vitro biocompatibility margins for our stimulation parameters applied to cells of the peripheral hearing organ were between 200 and 223 mW (3348  J/cm2). After irradiation with a subphototoxic laser power of 199 mW (2988  J/cm2), only the fibroblasts showed a significant upregulation of GADD45G.

CONCLUSION

Further studies are underway to optimize parameters for the optoacoustic stimulation of the auditory system. Our protocol and results on laser-tissue interactions can be useful for translational laser applications in various other irradiated biological tissues.

Photobiomodulation effects on osteogenic differentiation of adipose-derived stem cells

Increasing interest has been observed in the use of photobiomodulation (PBM) to enhance the proliferation of stem cells and induce their differentiation. The effects of PBM at two different wavelengths (635 and 809 nm) with three different energy densities (0.5, 1 and 2 J/cm²) on the osteogenic differentiation of adipose-derived stem cells (ADSC) were investigated. Cell viability and proliferation were evaluated by MTT and Alamar Blue assays. Osteoblast differentiation were assessed by alkaline phosphatase (ALP) activity, Alizarin red staining and reverse-transcription polymerase chain reaction (RT-PCR) for the expression of collagen type I (COL1A), ALP and osteocalcin. 635 nm and 809 nm laser irradiation had no effect on the cell viability on days 7 and 14, except for 0.5 J/cm² group at 14th day after 635 nm irradiation (p < 0.05). Cell proliferation was not changed significantly. Mineralization was increased significantly in 809 nm laser groups but no enhancement was detected in the osteogenic differentiation by ALP activity and gene expression results. In 0.5 and 1 J/cm² groups, ALP and COL1A expressions were down regulated at day 7 after 809 nm laser exposure. These results suggest that PBM may alter osteogenic differentiation of ADSC and increase mineralization but further investigation is needed to define adequate parameters.

Effect of Laser Therapy on the Osseointegration of Immediately Loaded Dental Implants in Patients under Vitamin C, Omega-3 and Calcium Therapy

BACKGROUND:

The use of laser therapy in the biostimulation of bone repair has been growing steadily.

AIM:

This study aimed to evaluate the radio-densitometric effect of low-intensity laser therapy on the osseointegration of immediately loaded dental implants in patients under vitamin C, omega-3 and calcium therapy.

PATIENTS AND METHODS:

A single implant was placed in the mandibular first molar region of twenty patients which were equally divided into two groups. In the non-laser group, the healing phase was left to progress spontaneously without any intervention, while in the laser group it was augmented with low-level laser therapy of wavelength 904 nm in contact mode, continuous wave, 20 mW output power and exposure time 30 sec with a dose 4.7 J/cm². Patients in both groups were given vitamin C, calcium and omega-3 starting one month preoperatively. Postoperative digital panoramas were taken immediately after surgery, 1.5 months and 6 months postoperatively. Changes in bone density along the bone-implant interface at the mesial, distal and apical sides were assessed using the Digora software.

RESULTS:

Independent student t-test was used to compare means of variables between the laser and the non-laser group while repeated measures ANOVA was used to compare bone densities at different times for the same group. Significant increased differences were observed at the mesial, distal and apical sides surrounding the implants of both groups per time. However, the rate of increase was significantly higher in the laser group. The mean difference at the mesial side after 6 months was 21.99 ± 5.48 in the laser group and 14.21 ± 4.95 in the non-laser group, while it read 21.74 ± 3.56 in the laser group and 10.78 ± 3.90 in non-laser group at the distal side and was 18.90 ± 5.91 in the laser group and 10.39 ± 3.49 in non-laser group at the apical side. Significance was recorded at P = 0.004, P = 0.0001, and 0.001 at the mesial, distal and apical sides respectively.

CONCLUSION:

The low-intensity laser irradiation significantly promoted bone healing and speeded up the osseointegration process emphasising the laser’s biostimulatory effect.

Combination of chemotherapy and Au-nanoparticle photothermy in the visible light to tackle doxorubicin resistance in cancer cells

Despite great advances in the fight against cancer, traditional chemotherapy has been hindered by the dose dependent adverse side effects that reduce the usable doses for effective therapy. This has been associated to drug resistance in tumor cells that often cause relapse and therapy failure. These drawbacks have been tackled by combining different therapeutic regiments that prevent drug resistance while decreasing the chemotherapy dose required for efficacious ablation of cancer. In fact, new metallic compounds have been in a continuous development to extend the existing chemotherapy arsenal for these combined regimens. Here, we demonstrate that combination of a metallic compound (TS265), previously characterized by our group, with photothermy circumvents cells resistant to Doxorubicin (DOX). We first engendered a colorectal carcinoma cell line (HCT116) highly resistant to DOX, whose viability was diminished after administration of TS265. Cancer cell death was potentiated by challenging these cells with 14 nm spherical gold nanoparticles followed by laser irradiation at 532 nm. The combination of TS265 with photothermy lead to 65% cell death of the DOX resistant cells without impacting healthy cells. These results support the use of combined chemotherapy and photothermy in the visible spectrum as an efficient tool for drug resistant tumors.

Comparative study on the effect of low intensity laser and growth factors on stem cells used in experimentally-induced liver fibrosis in mice

BACKGROUND AND STUDY AIMS

The therapeutic effects of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) exposed to diode laser and/or hepatocyte growth factor (HGF) were compared in mice with experimental liver fibrosis induced by carbon tetra chloride (CCl₄).

MATERIAL AND METHODS

Animal model of liver cirrhosis was induced by intraperitoneal injection of CCl₄ in a dose of 0.4ml/kg, twice a week for 6weeks. UC-MSCs were obtained from normal full term placentas and were exposed to diode laser and/or HGF. Before treatment, UC-MSCs were labelled with red fluorescent PKH26. Fifty four male mice weighing 25-35g were randomly divided into four groups control, stem cells, CCl₄, and treated groups. After the experimental period, body and liver weights were recorded, and the liver specimens were processed for histological examination using haematoxylin and eosin, Periodic Acid-Schiff (PAS), and Masson's Trichrome staining (MT).

RESULTS

Results showed that administration of UC-MSCs stimulated by diode laser and/or HGF improved body and liver weights, reduced vascular dilatation and congestion, reduced mononuclear cellular infiltration, reduced hepatocyte vacuolation, eosinophilia, and pyknosis. Furthermore, periportal fibrosis was minimized and PAS reaction was increased. These effects were maximum when UC-MSCs were exposed to both diode laser and HGF.

CONCLUSION

UC-MSCs stimulated by both diode laser and HGF proved to be an effective therapeutic option in experimental liver fibrosis induced by CCl₄ in mice.

Effect of low-level laser therapy on angiogenesis and matrix metalloproteinase-2 immunoexpression in wound repair

Low-level laser therapy (LLLT) induces anti-inflammatory and angiogenic activities in wound healing. However, the mechanism of action and optimal parameters require further clarification. In this study, we investigated the effects of LLLT on wound healing matrix metalloproteinase (MMP)-2 immunoexpression and angiogenic processes. Twenty female Wistar rats were randomly divided into four groups (n = 5) according to the treatments as follows. CG7 and CG14 were control groups at days 7 and 14, respectively, which received physiological saline (0.9 % NaCl daily). LG7 and LG14 were laser therapy groups at days 7 and 14, respectively, which received two (LG7) or four (LG14) LLLT applications (40 mW; 660 nm; 4 J/cm²). A dorsal skin sample in the wound area (measuring 2 cm²) was removed after the experimental period, and then the animals were euthanized. The specimens were processed for qualitative and quantitative histological analyses and measurement of MMP-2 expression in the dermis and epidermis. A persistent crust and moderate number of inflammatory cells were found in CG7 and CG14 groups. In the LG14 group, wounds demonstrated complete re-epithelization at the remodeling phase. Angiogenesis and MMP-2 expression were higher in LLLT-treated groups, particularly the LG14 group, which correlated according to the Spearman correlation test. LLLT improves wound healing by enhancing neocollagenesis, increasing the amount of new vessels formed in the tissue (neoangiogenesis), and modulating MMP-2 expression. Epidermal overexpression of MMP-2 was correlated to angiogenic processes.

[The influence of continuous low-intensity laser radiation at the red (635 nm) and green (525 nm) wavelengths on the human mesenchymal stem cells in vitro: a review of the literature and original investigations]

Low-intensity laser radiation can be used as one of the methods for the non-specific regulation of the human mesenchymal stem cell (MSC) activity at the preliminary stage of their in vitro cultivation. The objective of the present study was to estimate the influence of the limiting regimes of continuous low-intensity laser radiation (CLIR) of red (635 nm) and green (525 nm) spectra.

MATERIAL AND METHODS

The adhesive culture of human mesenchymal stem cells obtained from a donor's umbilical cord tissue was used in the experiments (following 4 passages). They were irradiated using a Lazmik-VLOK laser therapeutic device equipped with the KLO-635-40 (635 nm, 4,9 mW/cm(2)) and KLO-525-50 (525 nm, 5,4 mW/cm(2)) laser diode emitting heads operating in a continuous mode. A special nozzle (jar) for laser and vacuum massage (KB-5, 35 cm in diameter) was employed to fix the heads. The exposure time in all the irradiation regimes was 5 minutes.

CONCLUSION

The study has demonstrated that neither the morphological features nor the viability of mesenchymal stem cells was altered under the influence of laser irradiation at the aforementioned energy and time parameters. The data obtained indicate that laser irradiation with the limiting levels of the chosen energy parameters produces no positive effect on the cell proliferative activity; more than that, it may cause its inhibition.

Effect of Photobiomodulation on Mesenchymal Stem Cells

OBJECTIVE

The purpose of this study was to review available literature about the effect of photobiomodulation (PBM) on mesenchymal stem cells (MSCs).

BACKGROUND DATA

The effects of coherent and noncoherent light sources such as low-level lasers and light-emitting diodes (LEDs) on cells and tissues, known as PBM, form the basis of photomedicine. This treatment technique effects cell function, proliferation, and migration, and plays an important role in tissue regeneration. Stem cells have been found to be helpful elements in tissue regeneration, and the combination of stem cell therapy and laser therapy appears to positively affect treatment results.

MATERIALS AND METHODS

An electronic search in PubMed was conducted of publications from the previous 12 years. English language articles related to the subject were found using selected key words. The full texts of potentially suitable articles were assessed according to inclusion and exclusion criteria.

RESULTS

After evaluation, 30 articles were deemed relevant according to the inclusion criteria. The energy density of the laser was 0.7-9 J/cm². The power used for visible light was 30-110 mW and that used for infrared light was 50-800 mW. Nearly all studies showed that low-level laser therapy had a positive effect on cell proliferation. Similar outcomes were found for LED; however, some studies suggest that the laser alone is not effective, and should be used as an adjunct tool.

CONCLUSIONS

PBM has positive effects on MSCs. This review concluded that doses of 0.7-4 J/cm² and wavelengths of 600-700 nm are appropriate for light therapy. The results were dependent upon different parameters; therefore, optimization of parameters used in light therapy to obtain favorable results is required to provide more accurate comparison.

532 nm Low-Power Laser Irradiation Facilitates the Migration of GABAergic Neural Stem/Progenitor Cells in Mouse Neocortex

BACKGROUND AND OBJECTIVE

Accumulating evidence has shown that low-power laser irradiation (LLI) affects cell proliferation and survival, but little is known about LLI effects on neural stem/progenitor cells (NSPCs). Here we investigate whether transcranial 532 nm LLI affects NSPCs in adult murine neocortex and in neurospheres from embryonic mice.

STUDY DESIGN/MATERIALS AND METHODS

We applied 532 nm LLI (Nd:YVO4, CW, 60 mW) on neocortical surface via cranium in adult mice and on cultured cells from embryonic mouse brains in vitro to investigate the proliferation and migration of NSPCs and Akt expression using immunohistochemical assays and Western blotting techniques.

RESULTS

In vivo experiments demonstrated that 532 nm LLI significantly facilitated the migration of GABAergic NSPCs that were induced to proliferate in layer 1 by mild ischemia. In vitro experiments using GABAergic NSPCs derived from embryonic day 14 ganglionic eminence demonstrated that 532 nm LLI for 60 min promoted the migration of GAD67-immunopositive NSPCs with a significant increase of Akt expression. Meanwhile, the LLI induced proliferation, but not migration, of NSPCs that give rise to excitatory neurons.

CONCLUSION

It is concluded that 532 nm LLI promoted the migration of GABAergic NSPCs into deeper layers of the neocortex in vivo by elevating Akt expression.

Effects of low level laser therapy on attachment, proliferation, and gene expression of VEGF and VEGF receptor 2 of adipocyte-derived mesenchymal stem cells cultivated under nutritional deficiency

Low-level laser therapy (LLLT) has been shown to increase the proliferation of several cell types. We evaluated the effects of LLLT on adhesion, proliferation, and gene expression of vascular endothelial growth factor (VEGF) and type 2 receptor of VEGF (VEGFR2) at mesenchymal stem cells (MSCs) from human (hMSCs) and rat (rMSCs) adipose tissues on nutritional deficiencies. A dose-response curve was performed with cells treated with laser Ga-Al-As (660 nm, 30 mW) at energy of 0.7 to 9 J. Cell adhesion and proliferation were quantified 20, 40, and 60 min after LLLT and 24, 72, and 120 h after cultivation. Gene expression was verified by RT-PCR after 2 h of LLLT. A minor nutritional support caused a significant decrease in proliferation and adhesion of hMSCs and rMSCs. However, at the lowest LLLT dose (0.7 J), we observed a higher proliferation in hMSCs at standard condition shortly after irradiation (24 h). Adhesion was higher in hMSCs cultivated in controlled conditions at higher LLLT doses (3 and 9 J), and rMSCs show a reduction in the adhesion on 1.5 to 9 J. On nutritional deprivation, a 9 J dose was shown to reduce proliferation with 24 h and adhesion to all culture times in rMSCs. VEGF and VEGFR2 were increased after LLLT in both cell types. However, hMSCs under nutritional deprivation showed higher expression of VEGF and its receptor after irradiation with other laser doses. In conclusion, LLLT on human and rat MSCs might upregulate VEGF messenger RNA (mRNA) expression and modulate cell adhesion and proliferation distinctively.

A nonsense mutation in TMEM95 encoding a nondescript transmembrane protein causes idiopathic male subfertility in cattle

Genetic variants underlying reduced male reproductive performance have been identified in humans and model organisms, most of them compromising semen quality. Occasionally, male fertility is severely compromised although semen analysis remains without any apparent pathological findings (i.e., idiopathic subfertility). Artificial insemination (AI) in most cattle populations requires close examination of all ejaculates before insemination. Although anomalous ejaculates are rejected, insemination success varies considerably among AI bulls. In an attempt to identify genetic causes of such variation, we undertook a genome-wide association study (GWAS). Imputed genotypes of 652,856 SNPs were available for 7962 AI bulls of the Fleckvieh (FV) population. Male reproductive ability (MRA) was assessed based on 15.3 million artificial inseminations. The GWAS uncovered a strong association signal on bovine chromosome 19 (P = 4.08×10⁻⁵⁹). Subsequent autozygosity mapping revealed a common 1386 kb segment of extended homozygosity in 40 bulls with exceptionally poor reproductive performance. Only 1.7% of 35,671 inseminations with semen samples of those bulls were successful. None of the bulls with normal reproductive performance was homozygous, indicating recessive inheritance. Exploiting whole-genome re-sequencing data of 43 animals revealed a candidate causal nonsense mutation (rs378652941, c.483C>A, p.Cys161X) in the transmembrane protein 95 encoding gene TMEM95 which was subsequently validated in 1990 AI bulls. Immunohistochemical investigations evidenced that TMEM95 is located at the surface of spermatozoa of fertile animals whereas it is absent in spermatozoa of subfertile animals. These findings imply that integrity of TMEM95 is required for an undisturbed fertilisation. Our results demonstrate that deficiency of TMEM95 severely compromises male reproductive performance in cattle and reveal for the first time a phenotypic effect associated with genomic variation in TMEM95.

Impaired male fertility is a prevalent condition in many species and is often explained by aberrant semen quality. In some cases, male fertility is severely compromised although semen quality is without any apparent pathological findings (i.e., idiopathic male subfertility). The genetic mechanisms underlying idiopathic male subfertility often remain unexplained. In the present paper, we report a recessively inherited variant of idiopathic male subfertility in a cattle population. We use 650,000 genome-wide SNP markers genotyped in >7900 artificial insemination bulls to pinpoint the underlying genomic region. We take advantage of whole-genome re-sequencing data of 43 animals to identify a causal loss-of-function mutation in TMEM95 encoding a nondescript transmembrane protein. We demonstrate that transmembrane protein 95 is located at the plasma membrane of spermatozoa of fertile animals whereas it is absent in spermatozoa of subfertile animals. Our results indicate that integrity of transmembrane protein 95 is required for an undisturbed fertilisation. This is the first report to reveal a phenotypic effect associated with genomic variation in TMEM95 in any organism.