Observations from clinical trials have frequently demonstrated that light therapy can be an effective therapy for seasonal and non-seasonal major depression. Despite the fact that light therapy is known to have several advantages over antidepressant drugs like a low cost, minimal side-effects, and fast onset of therapeutic effect, the mechanism underlying light therapy remains unclear. So far, it is known that light therapy modulates mood states and cognitive functions, involving circadian and non-circadian pathways from retinas into brain. In this review, we discuss the therapeutic effect of light on major depression and its relationship to direct retinal projections in the brain. We finally emphasize the function of the retino-raphe projection in modulating serotonin activity, which probably underlies the antidepressant effect of light therapy for depression.
Animals ; Brain ; radiation effects ; Depressive Disorder, Major ; therapy ; Humans ; Phototherapy ; methods ; Retina ; radiation effects ; Visual Pathways ; radiation effects

OBJECTIVETo investigate the injury effects of microwave on the visual performance and the apoptosis of retinal ganglion cells (RGCs) in rats and the relationship between the impaired visual performance and RGCs apoptosis induced by microwave.

METHODSThe visual performance of rats was observed by Electroretinogram (ERG) and Flash visual evoked potentials (F-VEP). The apoptosis of RGCs in vivo and in vitro was detected by TUNEL assay and Hoechst staining.

RESULTSMicrowave exposure had no influence on ERG-a wave. The amplitude of ERG-b wave decreased significantly on the 3rd day and 7th day after microwave exposure (P < 0.01).The latency of ERG-b wave shortened significantly only at 3rd day after microwave exposure (P < 0.01). The latency of F-VEP extended markedly on the 3rd day after exposure (P < 0.05) and recovered on the 7th day after microwave exposure. The amplitude of F-VEP decreased significantly in exposure group, as compared with sham-exposure group, on the 3rd day and 7th day after microwave exposure (P < 0.05). After microwave exposure for 12 h, the apoptotic rate of RGCs in rat increased from 2.85% to 6.73%, and on the 7th day after exposure, the apoptotic rate of RGCs remained 8.93% (P < 0.05). The apoptotic rate of cultured RGCs increased from 8.42% to 13.91% at 6 hour (P < 0.05) and to 24.14% at 24 hour (P < 0.01) after microwave exposure (P < 0.05 or P < 0.01).

CONCLUSIONMicrowave exposure can injure the visual performance of rats, and the apoptosis of RGCs induced microwave may be one of the main pathological mechanisms.

Animals ; Apoptosis ; radiation effects ; Cells, Cultured ; Male ; Microwaves ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Retina ; radiation effects ; Retinal Ganglion Cells ; pathology ; radiation effects

Transpupillary retinal photocoagulations were performed on ten eyes of five pigmented rabbits using a diode laser (Nidek Co., LTD, Aichi, Japan) emitting infrared radiation at 800 nm wavelength. A histological and an ultrastructural study on the treated eyes were done at 1, 3, 5, and 7 days after retinal photocoagulations. The purpose of this study was to observe the sequential changes in the retina and the choroid following transpupillary diode laser retinal photocoagulations at the parameters of laser power which produced a grayish white retinal discoloration with distinct white center. It seemed that the lesion was grade 3 retinal photocoagulation by Tso et al's classification. It appeared that the parameters necessary to produce grade 3 photocoagulation lesions were 160 mW power, and 0.2 second duration at 200 microns size. In general, with an agreement to other reports, histologic study of the diode laser lesions showed that the outer retina was damaged more severely than the inner retina. However, on day 1 after laser treatment, the alterations were more profound in the inner retina than in the outer retina and an occasional swelling of the axons in the nerve fiber layer was observed on the ultrastructural study. The results observed have not been found in other previous studies and suggest that the inner retina might be injured directly by 800 nm wavelength diode laser radiations. Thus we could conclude that 800 nm wavelength diode radiation might be absorbed by melanin pigment and also by other chromophores contained in inner retinal tissues. Further studies must follow to verify the laser-tissue interactions in diode laser retinal photocoagulations.
Animals ; Laser Coagulation/*adverse effects ; Rabbits ; Retina/pathology/*radiation effects/ultrastructure

OBJECTIVETo investigate the changes of cholinergic neurotrophic factors (CNTF) protein at different time points and the distribution of CNTF in rabbit retina after exposure to high power microwave (HPM), in order to determine the changes rule of CNTF protein.

METHODSThe rabbits were irradiated by HPM (peak power 90 W/cm(2)) for 15 min respectively, and then killed at 0, 3, 6, 12, 24 and 72 h after irradiation. The changes of CNTF protein were investigated by immunohistochemistry and semi-quantity analysis.

RESULTSCNTF protein was distributed in full retinal layers, special in the cell membrane and cytoplasm. HPM irradiation could immediately down-regulated CNTF protein expression at 0 h, up-regulated and arrived at peak level at 6 h (P<0.05 vs 0 h group), and then kept control level.

CONCLUSIONHPM may cause acute retinal injure and change the expression of CNTF protein in rabbit retina. These effects show the time-dependent feature. These results suggest that CNTF activation plays a central role in the retinal injures induced by HPM, and supplies a therapy method by using foreign-aid CNTF to remedy the retinal injure induced by HPM.

Animals ; Ciliary Neurotrophic Factor ; metabolism ; Female ; Male ; Microwaves ; adverse effects ; Rabbits ; Retina ; metabolism ; radiation effects

OBJECTIVETo investigate the role of Caspase-3 in retinal damage caused by light exposure in rats.

METHODSLight injury to retina was induced by persistent exposure to illumination (intensity: 30 000 +/- 50 lux) of operating microscope for 30 minutes in the right eyes of Sprague-Dawley rats. The pathological changes of retina were observed under optical and electron microscopies at different time points, which were 6 hours, 1, 3, 7, and 15 days after the light exposure. Apoptosis of retinal cells was analyzed by flow cytometry. The activity of Caspase-3 was evaluated by using the Caspase-3 assay kit. At the same time, the expression of Caspase-3 protease was determined with Western blot analysis.

RESULTSThe examination results of optical and transmission electron microscopes showed that edema of inner and outer segments of the retina, especially the chondriosome inside the inner segment, became obvious 6 hours after the light exposure. The change was deteriorated along with the increasing time. The structures of the discoidal valve dissociated in the outer segment simultaneously. Disorderly arranged nuclei, karyopycnosis, and thinning in the outer nuclear layer were observed. The retinal pigment epithelium almost disappeared during the later stage. The staining results of Annexin-V combined with PI demonstrated that the proportion of apoptotic cells increased with time. The proportion between 7th day (82.7%) and 15th day (80.4%), however, showed no significant difference. Caspase-3 became remarkably active with the lapse of time, which increased from 0.02 at 6th hour to the peak of 9.8 at 7th day before it started to descend. The Western blot detected a expression of the active form of Caspase-3 at 7th day and 15th day.

CONCLUSIONApoptosis of photoreceptor cells is markedly involved in the light damage and Caspase-3 protease may play an important role in the apoptotic process of the retina after light exposure in rats.

Animals ; Apoptosis ; radiation effects ; Caspase 3 ; genetics ; metabolism ; radiation effects ; Dose-Response Relationship, Radiation ; Enzyme Activation ; Gene Expression Regulation, Enzymologic ; radiation effects ; Light ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Retina ; enzymology ; pathology ; radiation effects ; ultrastructure

Animals ; Ciliary Neurotrophic Factor ; genetics ; metabolism ; Microwaves ; RNA, Messenger ; genetics ; Rabbits ; Retina ; metabolism ; radiation effects

This study aimed to evaluate the protective effect of heat shock protein70 (hsp70) on retinal photic injuries, and to determine the relationship between hsp70s from hsp70.1 and 70.3. C57BL/6 wild type (hsp70.1+/+) and knockout type (hsp70.1-/-) mice from the same littermates were placed in light of 11000 lux for 6 hours, and were sacrificed at 1, 4, 7, and 14 days after stress. H & E staining, immunohistochemistry, and western blot analysis were performed. The hsp70.1-/- mice exhibited more disarranged and more diffusely destroyed photoreceptors than the hsp70.1+/+ mice. Hsp70 induction by light in both the hsp70.1 +/+ and hsp70.1 -/- mice peaked at 1 day after light stress. The Hsp70 level in the hsp70.1 +/+ mice reduced slowly and was almost constant for 7 days. However, in the hsp70.1 -/- mice, it decreased rapidly and returned, after 7 days, to a similar level to that prior to light exposure. According to which gene they originate from, hsp70s may play specific roles in protecting the retina against stresses. Hsp70 from the hsp70.1 gene may act as a sustained responder to retinal photic injury.
Animals ; Blotting, Western ; Heat-Shock Proteins 70/*physiology ; Immunohistochemistry ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Radiation Injuries/*prevention& control ; *Radiation Protection ; Retina/*radiation effects ; Support, Non-U.S. Gov't

OBJECTIVETo study the effect of Vaccinium uliginosum L., (VU) on the electroretinogram (ERG) and retinal pathological changes in rabbits after light-induced damage.

METHODSTwenty-eight Chinchilla rabbits were randomly divided into four groups: administration beforehand (A), administration after injury (B), light injury without administration (C), and blank (D) groups. After a 4-week administration of VU homogenate at 4.8 g/(kg·d) once a day in group A, ERG in groups A, B and C were recorded according to the standards set by the International Society for Clinical Electrophysiology of Vision (ISCEV). Except for group D, the groups were then exposed to strong light. Just after that, group A stopped receiving VU treatment and group B started to receive it. Then ERGs in all groups were recorded after 1 day, 1 week, and 2 weeks. Throughout the whole process groups which were not fed with VU were fed with normal saline. Finally, the tissues and structures of all the groups were observed and the thickness of the outer nuclear layers (ONL) was measured.

RESULTS(1) After 4-week feeding with VU, the latency time of ERG in group A became shorter than those in the other groups and the amplitude increased. After being exposed to strong light, the latency time lengthened and amplitude decreased in all the injury groups, but comparing at each time point, the measured values in group A were better than those in group C. With the accumulation of VU, the ERG in group B improved, and finally, all of the detected values became better than those in group C. (2) Retinae in group D were normal in histology and the layers were in order but those in group C became disarranged. The injuries in groups A and B were minor compared with those in group C. The thickness of the ONL in group C was significantly thinner than in the other groups (P=0.000), and that in groups A and B was thicker than that in group C, although thinner than in group D. That in group A was thicker than in group B.

CONCLUSIONSVU can relieve the injury to rabbit retinae exposed to normal day and night rhythm, alleviate the harm caused by light when used beforehand, and repair the light damage to the retina.

Animals ; Electroretinography ; Light ; Plant Extracts ; pharmacology ; Rabbits ; Retina ; drug effects ; pathology ; physiopathology ; radiation effects ; Retinal Cone Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Retinal Rod Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Time Factors ; Vaccinium ; chemistry

OBJECTIVETo study the difference in stress and apoptosis related genes transcription between hTERT-RPE1 cells exposed to simulated microwave radiation and the cells with heat water bath, and the effects of microwave on gene transcription in cultured human retina pigment epithelial cells.

METHODScDNA microarray technique was used to detect the mRNA isolated from hTERT-RPE1 cells exposed to 2 450 MHz simulated microwave radiation and with heat water bath, respectively.

RESULTSAmong the 97 related aim genes, there were seven genes up-regulating its transcription, i.e., M31166 (2.52fold), L24123 (2.66fold), AF039704 (2.22fold), U67156 (2.07fold), AF040958 (2.13fold), NM-001423 (2.63fold) and NM-005346 (3.68fold). But, no notably down-regulating gene in transcription was detected.

CONCLUSIONSMicrowave could induce up-regulating in multiple stress and apoptosis related genes transcription in cultured human retina pigment epithelial cells, hTERT-RPE1 cells. Microwave radiation has unique effect itself in addition to its heat effect.

Gene Expression Profiling ; Gene Expression Regulation ; radiation effects ; Humans ; Microwaves ; Oligonucleotide Array Sequence Analysis ; methods ; Pigment Epithelium of Eye ; cytology ; metabolism ; radiation effects ; Retina ; cytology ; metabolism ; radiation effects ; Time Factors

BACKGROUNDMethanesulfonic acid sodium salt (Dipyrone), an antipyretic and analgesic drug, has been demonstrated to improve cerebral ischemia through the inhibition of mitochondrial cell death cascades. The aim of this study was to evaluate the potential photoprotective activity of methanesulfonic acid sodium salt in a model of light-induced retinopathy.

METHODSOne hundred mice were assigned randomly into vehicle (V), methanesulfonic acid sodium salt (D), light damage model plus vehicle (MV) and light damage model plus methanesulfonic acid sodium salt (MD) groups (n = 25 each). In the MD group, methanesulfonic acid sodium salt (100 mg/kg) was administered by intraperitoneal injection 30 minutes before light exposure. Twenty-four hours after light exposure, hematoxylin and eosin staining and transmission electron microscopy (TEM) were used for histological evaluation. The thickness of the outer plus inner-segment and outer nuclear layer was measured on sections parallel to the vertical meridian of the eye at a distance of 1000 mm from the optic nerve. Electroretinography (ERG) test was performed to assess the functional change. The morphology of mitochondria was also revealed by TEM. Finally, the expression of cytochrome c (CytC) and the relative apoptotic proteins were detected by Western blotting, and the interaction between mitochondrial proteins was investigated by co-immunoprecipitation.

RESULTSThe photoreceptor inner and outer segments of the MV group were significantly disorganized than the MD group. The thicknesses of the outer plus inner-segment layers and the outer nuclear layer, and the amplitudes of the a and b waves of the scotopic ERG response markedly decreased in the MV group compared to those in the MD group (P < 0.05). TEM examination revealed that the mitochondria of the MV group were distinctly swollen and contained disrupted cristae. In contrast, the morphology of mitochondria in the MD group was unaffected. Western blotting analysis showed that CytC, apoptosis proteinase activating factor-1 (Apaf-1), caspase 3, p53, p53-upregulated modulator of apoptosis (PUMA), Bax, and Bad were increased, whereas the anti-apoptotic proteins Bcl-2 and Bcl-X(L) were significantly decreased in the MV group than the MD group. Co-immunoprecipitation detection revealed that PUMA immunoreactivity precipitated by Bcl-X(L) decreased, whereas Bax immunoreactivity precipitated by Bcl-X(L) increased in the MD group compared to those in the MV group.

CONCLUSIONMethanesulfonic acid sodium salt is an effective photoprotective agent against light-induced retinopathy through the inhibition of CytC-mediated mitochondrial impairment.

Animals ; Apoptosis ; drug effects ; radiation effects ; Blotting, Western ; Electroretinography ; Immunoprecipitation ; Light ; adverse effects ; Male ; Mesylates ; therapeutic use ; Mice ; Microscopy, Electron, Transmission ; Mitochondrial Proteins ; metabolism ; Random Allocation ; Retina ; drug effects ; radiation effects ; ultrastructure ; Tumor Suppressor Protein p53 ; metabolism