Red Light Group Research Articles

Expression patterns of melatonin receptors in chicken ovarian follicles affected by monochromatic light.

Artificial illumination is an important exogenous factor in the control of many physiological and behavioral processes as well as an important environmental factor in the management of laying hens. Melatonin receptors are members of the G protein-coupled receptor family. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. The aim of this study was to examine the effect of monochromatic light on chicken egg reproduction and expression of melatonin receptors in chicken ovarian follicles. A total of 552 19-week-old hens were randomly divided into 4 groups with 138 birds in each group. Each group was randomly divided into 3 replicates with 46 birds in each replicate. Feed and water were provided for ad libitum. Light treatments were: control cool white (400-760 nm), blue (480 nm), green (560 nm), and red (660 nm). The short wavelength (blue light) group produced a greater total number of eggs at 300 days of age than did the long wavelength (red light) group, and the red light group showed higher melatonin receptor type 1A and melatonin receptor type 1C mRNA and protein expression. These results suggest that the wavelength of light is closely related to chicken egg number at 300 days of age; there is no effect of monochromatic light on melatonin receptor type 1B.

A clinical study of photodynamic therapy for chronic skin ulcers in lower limbs infected with Pseudomonas aeruginosa.

The objective of this study is to evaluate the antimicrobial activity and healing-promoting effect of topical photodynamic therapy (ALA-PDT) on chronic skin ulcers infected with Pseudomonas aeruginosa (PA). A total of 26 patients with chronic skin ulcers in lower limbs infected with PA were enrolled. The surface areas of the ulcers were treated with either δ-aminolevulinic acid (ALA)-mediated PDT (20% ALA solution, 1.5 h incubation, 630 nm red light, 80 J/cm(2)) or red light alone, both once a week for two weeks. Before treatment, the wound areas and the bacteria levels in these two groups were comparable (p > 0.05). Results indicated that the bacteria levels in the skin ulcers of the light only group of 24 h post-treatment (3.4 × 10(7) ± 7.1 × 10(7) CFU/cm(2)) and pre-treatment (5.5 × 10(7) ± 1.6 × 10(8) CFU/cm(2)) were not significantly different. In contrast, the bacteria levels on the surfaces of the ulcers in the PDT group of 24 h post-treatment (6.3 × 10(5) ± 1.7 × 10(6) CFU/cm(2)) and pre-treatment (8.9 × 10(7) ± 1.7 × 10(8) CFU/cm(2)) were significantly different (p < 0.01). At seven days post treatment, the mean ulcer area in the red light group was reduced from 11.85 ± 6.83 to 7.8 ± 4.9 cm(2) (p < 0.01), that of PDT group from 12.72 ± 8.58 to 3.4 ± 3.4 cm(2) (p < 0.01). Better healing was seen in PDT group (p < 0.01). In conclusion, ALA-PDT is a potential modality to control PA infection and promote healing of chronic skin ulcers in lower limbs.

Evaluation of 5-aminolevulinic acid-mediated photorejuvenation of neck skin

To evaluate the outcomes of the combination of red light or intense pulsed laser (IPL) with 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) in the treatment of photodamaged neck skin. The anterior of the neck was divided into four 2 cm × 2 cm sections and randomly assigned to red-light, red-light-PDT, IPL or IPL-PDT group. ALA cream of 5% was applied to PDT regions for 2h prior to light irradiation. Treatment was repeated once. The stratum corneum (SC) hydration, transepidermal water loss (TEWL), L(*), a(*), b(*) values, melanin index (MI), erythema index (EI), skin elasticity and skin thickness were examined by a blinded investigator. The function and volume of thyroid were also measured. After red-light-PDT, IPL-PDT and IPL treatment, the appearance of photoaging lesion was improved. The SC hydration, L(*) value, elasticity and thickness increased, whereas the TEWL and MI value decreased. These changes in red-light-PDT and IPL-PDT group were more obvious than IPL group. The a(*) and EI value increased in red-light-PDT group. No significant change was noticed in red-light group. Partial irradiation of the thyroid did not affect the function and volume of the thyroid. IPL-PDT and red-light-PDT showed better rejuvenation effect than IPL or red light alone on the neck skin.

The effect of monochromatic light-emitting diode light on reproductive traits of laying hens

Artificial illumination is an important exogenous factor in the control of many physiological and behavioral processes in the management of layers. The objective of this study was to examine the effect of monochromatic light on reproductive traits, fertility, and quality of eggs of local mountainous laying hens of China. Five hundred fifty-two19-wk-old hens were randomly divided into 4 groups, with each group consisting of 138 birds. Feed and water were provided ad libitum. Light treatments were control white (mini-incandescent light bulbs), blue (480 nm), green (560 nm), and red (660 nm). Birds maintained under green light produced fewer eggs than other groups. The red light group had a greater egg shape index than other groups and had greater fertility and hatchability than other groups. Egg weight was affected by light wavelength, but the rate of egg production was not. The ratio between egg components can be changed by the light source without changing the egg weight. Egg quality was the best for hens exposed to the green light.

Red light interferes in UVA-induced photoaging of human skin fibroblast cells.

The possible regulation mechanism of red light was determined to discover how to retard UVA-induced skin photoaging. Human skin fibroblasts were cultured and irradiated with different doses of UVA, thus creating a photoaging model. Fibroblasts were also exposed to a subtoxic dose of UVA combined with a red light-emitting diode (LED) for five continuous days. Three groups were examined: control, UVA and UVA plus red light. Cumulative exposure doses of UVA were 25 J cm(-2), and the total doses of red light were 0.18 J cm(-2). Various indicators were measured before and after irradiation, including cell morphology, viability, β-galactosidase staining, apoptosis, cycle phase, the length of telomeres and the protein levels of photoaging-related genes. Red light irradiation retarded the cumulative low-dose UVA irradiation-induced skin photoaging, decreased the expression of senescence-associated β-galactosidase, upregulated SIRT1 expression, decreased matrix metalloproteinase MMP-1 and the acetylation of p53 expression, reduced the horizon of cell apoptosis and enhanced cell viability. Furthermore, the telomeres in UVA-treated cells were shortened compared to those of cells in the red light groups. These results suggest that red light plays a key role in the antiphotoaging of human skin fibroblasts by acting on different signaling transduction pathways.

Role of Monochromatic Light on Development of Cecal Tonsil in Young Broilers

Previously, the different monochromatic lights have been demonstrated to affect splenocyte proliferation and melatonin (MEL) secretion in broilers. The present study was designed to evaluate the effects of different monochromatic lights on the development and immune function of broiler cecal tonsils, and to disclose the mechanisms underlying these phenomena. A total of 185 broilers (P0) including intact, sham-operated, and pinealectomized groups were exposed to blue light (BL), green light (GL), red light (RL), and white light (WL) by a light-emitting diode system for 14 days. Compared with RL groups, the GL in the intact and sham-operated groups showed larger follicle areas (66.70%), higher percentages of proliferating cell nuclear antigen (PCNA)-positive cells (33.33%), increased numbers of IgA(+) cells (48.60%), and increased antioxidase activity (33.33%-61.37%), whereas, the density of iNOS and MDA content in GL were lower (43.63%-54.43%) than that of RL. In contrast, after pinealectomy, the area of follicles, the percentage of PCNA-positive cells, the number of IgA(+) cells, and the antioxidase activity decreased in the different light treatments, but the density of iNOS and MDA content increased substantially. There was no significant difference in these parameters between broilers exposed to GL and other lights (P = 0.085-1.000). The results suggested that the enhanced effects of GL on the development and immune function of cecal tonsils in young broilers were mediated by elevated antioxidative status via up-regulation of MEL.

The Effects of Monochromatic Illumination on Early Eye Development in Rhesus Monkeys

Influence of longitudinal chromatic aberration (LCA) on emmetropization during early eye development has not been studied in primates. We investigated the effects of quasi-monochromatic lighting on refractive development and eye growth in rhesus monkeys. Infant rhesus monkeys were raised under one of three lighting conditions for 51 weeks: quasi-monochromatic blue light (peak 455 nm), red light (peak 610 nm), and white light (color temperature 5000 K). All animals underwent biometric measurements using cycloplegic streak retinoscope, keratometry, and A-scan ultrasonography for refraction, corneal power, and axial components, respectively, at designated time points. At the 51st week, the mean difference in refraction of the white light and blue light groups, compared with that of the red light group, reached 1.71 diopters (D) and 1.43 D, respectively (both P < 0.001). Two monkeys in the red light group developed myopia at the 16th week, whereas the other seven remained hyperopic throughout the experiment. No significant difference in mean refraction was observed between the blue light group and white light group. Illumination from long-wavelength light during early life could be a risk factor for the development of myopia in a small proportion of rhesus monkeys that are sensitive to L-cone stimulation.

Comparison of 5-aminolevulinic acid photodynamic therapy and red light for treatment of photoaging

The aim of this pilot study was to compare the efficacy of ALA-PDT and red light alone in the treatment of photoaging. A total of 14 adults with photoaging skin were recruited. ALA-PDT or red light alone was applied to the forearm extensor. Before and after treatment, the treated sites were examined by dermoscopy, the changes in straum corneum (SC) hydration, transepidermal water loss (TEWL), and the L*a*b* values were measured, and microscopic examination of collagens and elastins was performed. After ALA-PDT or red light illumination, the appearance of photoaging lesions improved, SC hydration increased and TEWL decreased. These changes in the ALA-PDT group were more obvious than those in the red light group. No significant change was noticed in the L*a*b* values in both groups. The signs of typical solar elastosis damage were improved in both groups. ALA-PDT showed better skin rejuvenation effect than red light alone.

A Preliminary Study of the Safety of Red Light Phototherapy of Tissues Harboring Cancer

Red light phototherapy is known to stimulate cell proliferation in wound healing. This study investigated whether low-level light therapy (LLLT) would promote tumor growth when pre-existing malignancy is present. LLLT has been increasingly used for numerous conditions, but its use in cancer patients, including the treatment of lymphedema or various unrelated comorbidities, has been withheld by practitioners because of the fear that LLLT might result in initiation or promotion of metastatic lesions or new primary tumors. There has been little scientific study of oncologic outcomes after use of LLLT in cancer patients. A standard SKH mouse nonmelanoma UV-induced skin cancer model was used after visible squamous cell carcinomas were present, to study the effects of LLLT on tumor growth. The red light group (n=8) received automated full body 670 nm LLLT delivered twice a day at 5 J/cm(2) using an LED source. The control group (n=8) was handled similarly, but did not receive LLLT. Measurements on 330 tumors were conducted for 37 consecutive days, while the animals received daily LLLT. Daily tumor measurements demonstrated no measurable effect of LLLT on tumor growth. This experiment suggests that LLLT at these parameters may be safe even when malignant lesions are present. Further studies on the effects of photoirradiation on neoplasms are warranted.

Visible light induce oxidative damage to human retinal pigment epithelial cells

Objective To observe the effect of visible light (white light, red light, blue light) on the expression of reactive oxygen species (ROS), 8-OHdG and hOGG1 in cultured human retinal pigment epithelial (RPE) cells. Methods Cultured human RPE-19 cells (4th-6th generations) were divided into white light, red light, blue light and control group. The illumination was 600 Lux. The cells of experimental groups were exposed to white light or red light for 6, 12, 24 and 48 hours, and exposed to blue light for 1, 3, 6 and 12 hours, while cells of the control group were cultured in foil packaged dishes to avoid light. The levels of ROS expression were detected by 2′, 7′-dichlorofluorescin-diacetate (DCFH-DA), the levels of 8-OHdG protein expression were observed by immunocytochemistry (ICC), and the levels of hOGG1 were measured by western blot. Results Compared to the control group, the ROS expression in RPE cells were increased in white and red light group after 12, 24 and 48 hours and in blue light group after 1, 3, 6 and 12 hours (Fwhite light=11. 611, Fred light =6.706, Fblue light =23. 259; P＜0.05 ). Additionally, the ROS expression had a tendency to increase gradually along with exposure time. Compared to the control group, the 8-OHdG expression in RPE cells were increased significantly in both white and red light group after 12, 24 and 48 hours and in blue light group after 1, 3, 6 and 12 hours (Fwhite light =16. 032,Fred light =6. 378, Fblue light =19. 484; P＜0.05). Additionally, the 8-OHdG expression in white and red light group were increased gradually with exposure time but decreased when exposure time was up to 48 hours, while that in blue light group was increased firstly though it started to decrease when exposure time was up to 6hours. Compared to the control group, the hOGG1 expression in RPE cells were increased in white and red light group after 12, 24 and 48 hours and in blue light group after 6 and 12 hours (Fwhite light =15. 121,Fred light=21. 041,Fblue light12. 479; P＜0.05). ConclusionsExposure to white, red or blue light could induce ROS production and DNA oxidative damage in RPE cells in a time-dependent way. Exposure to visible light could switch on self protection of RPE cells against DNA oxidative damage by up-regulating of the hOGG1 expression. Key words: Pigment epithelium of eye/ cytology; Reactive oxygen species; Deoxyguanine nucleotides; Cell culture techniques

Effects of different wave-length lights on proliferation and secretion of growth factors in human retinal pigment epithelium cells

Background The study of myopia development is always the hotspot worldwide. Recently,scientist found that some growth factor secreted by retinal nerve epithelium cells and retinal pigment epithelium(RPE)cells are associated with the development of myopia. Whenever, the absorption of RPE cells to different wave-length lights is different. ObjectiveThis study was to investigate the effects of different wave-lengths lights on the proliferation of human RPE cells, and explore the influence of different wave-lengths lights on RPE cells secreting hepatocyte growth factor(HGF) ,basic fibroblast growth factor(bFGF) and transforming growth factor-β(TGF-β).Methods The fourth to fifth passages of human embryonic RPE cells were exposed to blue light( λ =480 nm),red light( λ =775 nm) and white light. The cells of control group were harvested in normal condition. The proliferation and growth of RPE cells were assayed by MTT,and the ultrastructure of cells was examined under the transmission electron microscopy at 48 hours after light exposure of RPE cells. Enzyme linked immunosorbent assay(ELISA) was adopted to determine the concentrations of HGF,bFGF and TGF-β in the culture medium in 12,24,48,72 hours. The expression of HGF mRNA in RPE cells was detected by RT-PCR. This study was approved by Ethic committee of Fudan University. Results The A490 values of the cells exposed to blue light,red light,white light and white light were 0. 0218±0. 0014 ;0. 0353±0. 0025 ;0. 0371 ±0. 0024 and 0. 0445 +0. 0046 respectively with the significant difference among 4 groups ( F =12. 579, P＜0.05 ), and A490 value in blue light group, red light group were significantly lower than that of the control group ( t =2.043 ; t =2.024, P＜0.05 ). ELISA showed that the concentrations of HGF and TGF-β in culture medium were evidently elevated as the prolongation of light exposure in various light exposure groups in 72 hours(HGF) and 48 hours(TGF-β) compared with 12 hours with a predominating rise in the control group. The statistically significant differences were found in the concentrations of HGF and TGF-β between control group and blue light group or red light group in the( all P＜0. 05 ). The bFGF level was decreased with the time increase of various light exposure with the significant differences in 72 hours compared with 12 hours( P＜0.05 ). RT-PCR revealed the considerable difference about expression of HGF mRNA in RPE cells among these four groups( P＜0. 05 ), and the lest expression in HGF mRNA was in the blue light group compared with control group( t =3. 972,P＜0.05 ). Thinning of the chromatin, decreasing of organelle and loss of cellular membrane were seen in the blue light group, but no obvious change of ultrastructure of human embryo RPE cells was found in the ret and white light groups. Conclusions The irradiation of different wave-length light can effect the growth and proliferation and secretion of HGF,bFGF and TGFβ in human RPE cells in vitro,implying myopia formation is associated to exposure of different wave-length light. Key words: Myopia; Retinal pigment epithelial cell; Hepatocyte growth factor; Basic fibroblast growth factor; Transforming growth factor-β ; Light exposure

Effect of Laser Acupuncture for Monosymptomatic Nocturnal Enuresis on Bladder Reservoir Function and Nocturnal Urine Output

The alternative treatments for enuresis have been reported with high efficacy but in noncontrolled studies. Therefore, using a prospective, single-blind, randomized, placebo controlled design we evaluated the effect of laser acupuncture on bladder reservoir function and enuresis frequency in cases of monosymptomatic nocturnal enuresis with reduced maximal voided volume. A total of 31 patients with monosymptomatic nocturnal enuresis, with at least 3 enuretic nights per week and less than 70% of normal age related maximal voided volume without first morning void (Koff's formula), no constipation, urinary tract abnormalities, or daytime incontinence were randomized into group 1--active laser acupuncture, group 2--placebo treatment with red light and skin contact and group 3--placebo treatment with red light without skin contact. After a 2-week run-in period (when patients made home recordings of nocturnal urinary production and during 2 weekends frequency-volume charts), the patients started a 5-week treatment. During the last 2 weeks of treatment patients performed the same recordings as during the run-in period. We found no significant effect of active laser acupuncture on maximal voided volume (first morning void excluded), maximal morning voided volume, voiding frequency, enuresis frequency before and after treatment or nocturnal urine production among the patient groups. However, we found that laser acupuncture resulted in a significant increase in average daytime voided volume. We found no effect of skin contact during placebo laser acupuncture. Laser acupuncture is a safe but inefficient treatment for monosymptomatic nocturnal enuresis with reduced maximal voided volume. However, we found subtle effects on bladder reservoir function.

Effects of Monochromatic Light on Developmental Changes in Satellite Cell Population of Pectoral Muscle in Broilers During Early Posthatch Period

To investigate the effects of various monochromatic lights on early posthatch changes in satellite cell mitotic activity of pectoral muscle, a total of 416 newly hatched broilers were exposed to blue light (BL), green light (GL), red light (RL), and white light (WL) by light emitting diode system for 3 weeks, respectively. Both, in culture and in vivo studies showed that after hatching, the relative number of satellite cells altered in correlation. The enhancement of satellite cell mitotic activity peaked at post-hatching day (P) 3 and then declined with age concomitantly with the rise in satellite cell differentiation and reduction of satellite cell proliferation. These alterations became more obvious in GL than in RL. The data suggested that early posthatch changes in satellite cell population of broilers occurred through the two different processes, i.e., cellular generation (before P3) and cellular degeneration (after P3). GL promoted significantly the broiler satellite cells to proliferate before P3 and to differentiate after P3. In addition, the circulating insulin-like growth factor-I (IGF-I) levels were higher in GL and BL groups versus WL and RL groups at P3 and P5 indicating that IGF-I plays a central role for GL illumination promoting broiler satellite cell myogenic processes during early posthatch stages.

Light therapy by blue LED improves wound healing in an excision model in rats

Background Low level light therapy (LLLT) is an attractive alternative to enhance wound healing. So far most studies are performed with red or infrared irradiation. However, we recently showed that blue light (470 nm) can significantly influence biological systems, improving perfusion by release of nitric oxide from nitrosyl complexes with haemoglobin in a skin flap model in rats. Here, we compared the effects of blue and red low level light by light-emitting diodes (LEDs) on in vivo wound healing in an excision wound model in rats. Methods Circular excision wounds were surgically created on the dorsum of each rat. Excisions on either the left or right side were illuminated post-OP and on five consecutive days for 10 min by LED at 470 nm or 630 nm with an intensity of 50 mW/cm 2, while protecting the contralateral side from exposure. In the control group, neither side was illuminated. On day 7 post-OP, we analysed planimetric and histological parameters, as well as expression of keratin-1, keratin-10 and keratin-17 on mRNA level. Results Illumination substantially influenced wound healing. Blue light significantly decreased wound size on day 7, which correlated with enhanced epithelialisation. Light also affected mRNA expression. Both wavelengths decreased keratin-1 mRNA on day 7 post-OP, while keratin-10 mRNA level was elevated in both light treated group compared to control. Keratin-17 mRNA was also elevated in the red light group, but was unchanged in the blue light group. Conclusion In contrast to previous studies, we showed that also blue light significantly influences wound healing. Furthermore, our data suggest that light therapy can play an important role in normotrophic wound healing by affecting keratin expression. Illumination would provide an easily applicable, safe and cost-effective treatment of surface wounds.

Blue but not red light stimulation in the dark has antidepressant effect in behavioral despair

The present study investigated potential antidepressant effect of light exposure in the dark phase of a 12:12 L/D cycle on behavioral despair. In Exp.1, male Wistar rats were administered a single, 10min broadband light pulse (1300lx) either 3h (ZT15) or 9h (ZT21) after dark onset (ZT12) and tested in two consecutive swim tests separated by 24h. Photic stimulation at ZT21 but not ZT15 significantly reduced immobility in the second swim test relative to the first test compared to controls that were treated similarly except for light pulse administration (p<0.05). In Exp.2, groups were exposed to a single 10-min light pulse (1300lx) either in the blue or red end of the spectrum at ZT21 or were treated similarly except for photic exposure (controls). Exposure to blue light resulted in significantly reduced duration of immobility in the second swim test relative to that of the first test compared to the red light and control groups (p<0.05). The present findings suggest a critical role in the antidepressant effect of blue light stimulation for the melanopsin-containing ganglion cells in the retina that are sensitive to wavelengths in the blue but not red end of the visible spectrum.

Effects of Monochromatic Light on Proliferation Response of Splencyte in Broilers

To investigate the effects of various monochromatic lights on splenocyte proliferation responses, a total of 260 Arbor Acre male broilers on P1 (post-hatching day 1) were exposed to blue light (BL), green light (GL), red light (RL) and white light treatments by light emitting diode system for 7 weeks, respectively. All light sources were equalized on the intensity of 15 lx and light period of 23 h daily. Morphological change of spleen and response of splenocyte proliferation were assessed by using histochemistry staining and colorimetric test in cultures of purified splenic cells. The results were as follows: (1) At P21, GL increased significantly the spleen weight by 163.6% and spleen index by 118.8% compared with RL (P < 0.05). Until P49, BL enhanced significantly the spleen weights by 42.2% compared with RL (P < 0.05), but no significant difference was found in the spleen index among four light-treated groups (P > 0.05). (2) Compared with RL, GL increased significantly the diameter of splenic nodule and area of periarterial lymphatic sheath at P21 by 87.2 and 58.1%, respectively (P < 0.05); BL increased significantly the diameter of splenic nodule and area of periarterial lymphatic sheath at P49 by 64.4 and 50.5%, respectively (P < 0.05). (3) At P21, GL enhanced spleen lymphocytes proliferation in response to concanavalin A compared with RL by 50.0% (P < 0.05). Until P49, the mitogenic response in BL was significantly higher (29.4%) than that of RL (P < 0.05). (4) The interleukin-2 (IL-2) bioactivity was significantly increased to 34.3% in GL than in RL at P21 (P < 0.05). Until P49, the IL-2 bioactivity in BL was significantly higher (62.2%) than that of RL (P < 0.05). (5) There was no significant difference in the nitric oxide (NO) concentration of splenocyte among RL, GL and BL groups at P21 (P > 0.05), but the concentration in RL group at P49 was significantly increased, 59.0 and 63.7% compared to that of GL and BL groups, respectively (P < 0.05). These results suggested that the monochromatic light affected splenocyte proliferation mainly because of alterations in IL-2 bioactivity and NO production in splenocyte of broiler. In early stage of broiler growth, the action of GL was obvious, while the response of BL was stronger in later stage.

Effects of Monochromatic Light on Immune Response of Broilers

A total of 260 one-day-old Arbor Acres male broilers were exposed to red light (RL), green light (GL), blue light (BL), and white light (WL), respectively, by using a light-emitting diode system for 7 wk. There were 5 replicate pens for each light treatment and 13 birds per pen. The effects of monochromatic light on the immune response were studied. The results indicated that proliferation of peripheral blood T lymphocytes in the GL group was significantly increased (by 80.8 and 54.8%) compared with those in the RL and BL groups, respectively, at 21 d of age (P < 0.05). At 49 d of age, however, the proliferation response was significantly increased in the BL group compared with the RL group (26.9%, P< 0.05). Moreover, the GL group showed a significant elevation in the serum anti-Newcastle disease virus level as compared with that of the RL group at 28 d of age (32.9%, P < 0.05). In contrast, no significant difference in serum anti-Newcastle disease virus level was observed among the BL, RL, and WL groups at this age (P > 0.05). By 49 d of age, the antibody titer was higher in the BL group than in the RL group (62.8%, P < 0.05). However, no significant difference in antibody titer was seen among the BL, GL, and WL groups at this age. Interestingly, the BL group showed a 44.0% reduction in the level of serum interleukin-1β as compared with that in the RL group at 49 d of age (P < 0.05). These results suggest that GL and BL enhance the immune response better than RL, and that BL may play a role in alleviating the stress response in broilers.

A novel approach of LED light radiation improves the antioxidant activity of pea seedlings

Influence of light-emitting diode (LED) light on antioxidant activity of radiated pea seedlings was first studied using red (625–630 nm) and blue (465–470 nm) LED lights as light sources in an attempt to determine and compare the changes in chlorophyll and β-carotene contents, and Trolox equivalent antioxidant capacity (TEAC, μM). After radiation for 96 h, comparing to white light group, red light radiated seedlings displayed significant ( p < 0.05) increases in stem length and leaf area, while blue light radiation significantly ( p < 0.05) increased the stem length and seedling weight. Chlorophyll in leaves increased rapidly when seedlings were radiated by blue light but no significant ( p > 0.05) difference was observed among light radiated seedlings after 96-h cultivation. β-Carotene content of LED radiated leaves was significantly ( p < 0.05) higher in red light (54.47 ± 2.35 μg/g) group than in the others. TEAC value of ethanol and acetone extracts (50 mg/mL) of 240 pieces of red light radiated seedlings cultured for 96 h reached 106.48 and 81.68 μM, respectively, were higher than the other treatments. In conclusion, the contribution of red light to significant β-carotene expression and antioxidant activity for nutrition and health benefits and blue light to seedling weight and chlorophyll induction of radiated pea seedlings are emphasized.

Various light source treatments affect body and skeletal muscle growth by affecting skeletal muscle satellite cell proliferation in broilers

In this study we addressed the effect of various monochromatic light treatments on muscle growth and satellite cell proliferation in broilers ( Gallus domesticus). Broilers were reared under green (560 nm), blue (480 nm) and red (660 nm) monochromatic lights and white light as a control from day one until 35 days of age. At five days of age, satellite cells were prepared from the experimental chicks. The number of satellite cells per gram of breast muscle and total number of satellite cells derived from the experimental broilers was substantially higher in the groups reared under green and blue light, compared to the red and white light groups. Growth hormone receptor gene expression was also higher in the former groups. High correlation was found between the breast muscle weight observed on day 35 and the number of satellite cells per gram of breast muscle ( r=0.915) and total number of satellite cells ( r=0.833), derived from the experimental chicks as early as five days of age. In addition, the protein/DNA ratio found in breast muscle at 35 days of age was significantly lower in chicks that were reared under green and blue lights. The lowest ratio which was found in the green group and was twice as low as in the control group, indicates the highest number of nuclei in the former group. As satellite cells are the only source of additional nuclei in skeletal muscles of postnatal animals, our results suggest that the higher muscle weight found in the green and blue light groups was due to increased satellite cell proliferation during the first days of age.

The eye of the blue acara (Aequidens pulcher, Cichlidae) grows to compensate for defocus due to chromatic aberration.

By rearing fish in various monochromatic illuminations we investigated (1) the potential for compensation of refractive error due to chromatic aberration, (2) the contributions of the chromatic channels to emmetropization, and (3) the role of color cues in the control of eye growth. Cichlid fish (Aequidens pulcher) were reared for 6 months (12 h light/12 h dark) in monochromatic lights (623.5, 534.1, 485.0 nm; spectral purity 5-10 nm). Light levels were isoirradiant at 1.1.10(12) quanta/s/cm2. Two control groups were reared in white light with down-welling illuminances of 0.2 and 33 lx. Nasotemporal diameters (NTDs) of the eyes were measured in relation to lens size. Due to the oblique axis of highest acuity vision in cichlids, NTD is considered to be a more important dimension than axial length. Variances in NTD were equally small in all rearing groups. NTDs were enlarged with increasing wavelengths of the rearing lights with highly significant values over controls in the red-light group. The wavelength-dependent size of the eyes matched the changes in focal length due to longitudinal chromatic aberration. Complete recovery from eye enlargement was observed after fish reared in red light were exposed to a white light regime for 5 weeks. Small variances in NTD in all groups indicated stringent control of eye growth in the absence of color cues. The reversibility of the increase in NTD in fish reared in red light suggests that the eyes were emmetropized by visually guided mechanisms. Eye size in fish reared in white light was intermediate between the values expected if only blue-sensitive single or the red- and green-sensitive double cones contributed to the control of eye growth. This suggests that all chromatic channels participate in emmetropizing the fish eye.