Inhibitory effect of blue light intervention on lens-induced myopia development in guinea pigs and the mechanism of cone density change / 中华实验眼科杂志

Objective:To observe the effects of blue light intervention on the development of optical defocus-induced myopia in guinea pigs and investigate its underlying mechanisms.Methods:Forty-eight normal-grade two-week-old tricolor guinea pigs were randomly divided into a blue light group and a white light group, with 24 animals in each group.The right eye of guinea pigs was fitted with a -5.00 D lens to establish an optical defocus model as the experimental eye, while the left eye served as the control without any covering.Before the experiment and after 8-week intervention, the refractive power of guinea pigs was measured by streak retinoscopy.The anterior chamber depth, lens thickness, and axial length were measured by A-scan ultrasonography.Corneal curvature radius was determined using a keratometer.After 8-week intervention, the guinea pigs were euthanized through overanesthesia, and the right eyeballs were enucleated and the retinas were isolated.The density of S and M cone cells of the guinea pig retinal sections were observed via immunofluorescence staining.The expression of retinal retinoic acid was assessed by high-performance liquid chromatography.The expressions of retinoic acid receptor (RAR-β) in the retina and matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-2 (TIMP-2), and type Ⅰ collagen in the sclera were detected by real-time fluorescence quantitative PCR.Changes in scleral thickness were observed through hematoxylin-eosin staining.The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.The study protocol was approved by the Ethics Committee of Eye and ENT Hospital of Fudan University (No.2022ETKLD10032).Results:After 8 weeks of intervention, guinea pigs in the blue light group showed (0.63±0.12)D of relative hyperopia and a deceleration of axial elongation by (0.08±0.00)mm compared with the white light group in the right eye.In the left eye, guinea pigs in the blue light group showed (0.42±0.09)D of relative hyperopia and a deceleration of axial elongation by (0.08±0.00)mm compared with the white light group.The guinea pigs in blue light group showed (1.52±0.09)D of myopia in the right eye compared with the left eye, with an increase in axial elongation of (0.06±0.00)mm.The guinea pigs in white light group showed (1.66±0.07)D of myopia in the right eye compared with the left eye, with an increase in axial elongation of (0.13±0.00)mm, and the differences were statistically significant (all at P<0.05). The density of M cone cells was lower and density of S cone cells was higher in the blue light group in the dorsal and ventral sides of the retinal sections compared with the white light group, showing statistically significant differences ( t=32.33, 52.23, 42.09, 25.02; all at P<0.05). The deceleration of myopia progression in the blue light group was strongly positively correlated with the increase in S cone cell density on the ventral side ( r=0.95, P<0.01). The expression levels of retinoic acid, RAR-β, and MMP-2 were decreased, and expression levels of TIMP-2 and type Ⅰ collagen were increased in blue light group compared with the white light group, showing statistically significant differences ( t=18.73, 7.45, 3.72, 6.19, 9.03; all at P<0.05). The scleral thickness in the blue light group was (125.0±7.8)μm, which was significantly thicker than (102.0±6.3)μm in the white light group ( t=26.93, P<0.05). Conclusions:Blue light intervention can inhibit the progression of defocus-induced myopia in guinea pigs.Refractive power changes in guinea pigs may be influenced by alterations in retinal cone cell density, retinoic acid expression, and scleral collagen expression.

Conception and features of bacillary layer detachment / 中华实验眼科杂志

The separation of outer retinal photoreceptors in patients with toxoplasmosis chorioretinitis was first named bacillary layer detachment (BALAD), which was manifested as a split at the level of the photoreceptor inner segment myoid creating a distinctive intraretinal cavity in optical coherence tomography.Subsequently BALAD has been reported by many researchers in different diseases.In the outer retina, the myoid is a relatively weak structure in photoreceptor inner segment.When the outward force that promotes the attachment of the photoreceptor outer segment to the retinal pigment epithelium exceeds the tensile strength of the photoreceptor inner segment myoid, the myoid zone splits and BALAD occurs.BALAD has its unique multimodal imaging characteristics, and the identification of it can provide a new idea for the diagnosis, detection and treatment of ocular diseases.This paper reviewed the development of BALAD nomenclature, its anatomical structure, pathophysiological mechanism and multimodal image features.

Protective effects and mechanisms of LIF on cone photoreceptors from oxidant injury / 眼科新进展

Objective To investigate the role of leukemia inhibitory factor (LIF) in cell survival of cone photoreceptors and the underlying mechanism following oxidant injury.Methods 661W cells were cultured and randomly divided into normal control group,LIF intervention group,H2O2 intervention group,S3 I201 intervention group,H2O2 + LIF intervention group,H2O2 + S3I201 intervention group and H2O2 + LIF + S3I201 intervention group,according to the different intervention drugs.MTT assay and Western blot were used to detect the effects of LIF pretreatment on 661W activity and the expression of STAT3 protein and its phosphorylation level after oxidative damage.Using STAT3-specific inhibitor S3I201 to block the STAT3 signal transduction pathway,MTT assay and real-time PCR were used to detect the effects of STAT3 signaling pathway on 661 W activity and the mRNA expression of survivin bcl-2 and bcl-xi after oxidative damage.Results Compared to H2O2 intervention group,the relative protein expression of p-Tyr705-STAT3 was increased in H2O2 + LIF intervention group,the difference was statistically significant (P ＜ O.05);The relative protein expression of p-Tyr705-STAT3 was decreased in H2O2 + S3I201 intervention group,the difference was statistically significant (P ＜ 0.05).Compared to H2O2 intervention group,the cell activity of 661W cells was increased in H2O2 + LIF intervention group,the difference was statistically significant(P ＜0.05).Compared to H2O2 + LIF intervention group,the cell activity of 661W cells was decreased in H2O2 + LIF + S3I201 intervention group,the difference was statistically significant (P ＜ 0.05).Compared to normal control group,the mRNA expression of bcl-2 and bcl-xl were increased in LIF intervention group,H2O2 intervention group and H2O2 + LIF intervention group,the differences were statistically significant (all P ＜ 0.05).Compared to H2O2 + LIF intervention group,the mRNA expression of bcl-2 and bcl-xl were decreased in H2O2 + LIF + S3I201 intervention group,the differences were statistically significant (all P ＜ 0.05).Conclusion LIF has protective effect on oxidative injury of cone photoreceptors,and it may contribute to cell survival through activation of the STAT3 signaling transduction pathway and its related survivin.

Is there a relationship between outer retinal destruction and choroidal changes in cone dystrophy? / Existe uma relação entre a destruição da retina externa e alterações da coroide em distrofia de cones?

ABSTRACT Purpose: The aim of the present study was to use enhanced depth imaging optical coherence tomography (EDI-OCT) to investigate choroidal changes in patients with cone dystrophy (CD) and to correlate these findings with clinical and electroretinography (ERG) findings. Methods: This case-control study included 40 eyes of 20 patients with CD and 40 eyes of 40 age- and refraction-matched healthy individuals. Choroidal thickness (CT) measurements were obtained under the foveal center and at 500 and 1,500 μm from the nasal and temporal regions to the center of the fovea, respectively. EDI-OCT and ERG data were analyzed, and the correlations of CT with the best-corrected visual acuity (BCVA) and the central foveal thickness (CFT) were evaluated. Results: The mean subfoveal CTs in the CD and control groups were 240.70 ± 70.78 and 356.18 ± 48.55 μm, respectively. The subfoveal CT was significantly thinner in patients with CD than in the controls (p<0.001). The patients with CD also had significantly thinner choroids than the controls at each measurement location relative to the fovea (p<0.001). The subfoveal CT in the CD group correlated with CFT (p=0.012), but no significant correlation was found between the subfoveal CT and BCVA or photopic ERG responses. Conclusions: The present study demonstrated a significant thinning of the choroid in patients with CD. EDI-OCT is a useful technique for describing the choroidal changes occurring in CD. Future studies investigating the association between choroidal changes and outer retinal destruction or the disease stage may provide a better understanding of the pathophysiology of CD.

RESUMO Objetivo: O objetivo deste estudo foi a utilização de imagens de tomografia de coerência óptica com profundidade aprimorada (EDI-OCT) para investigar alterações da coroide em pacientes com distrofia de cones (CD) e correlacionar esses achados com os achados clínicos e de eletrorretinografia (ERG). Métodos: Este estudo de caso-controle incluiu 40 olhos de 20 pacientes com CD e 40 olhos de 40 indivíduos saudáveis com idades e refração pareados. As medidas da espessura da coroide (CT) foram obtidas sob o centro foveal e a 500 μm e 1.500 μm de distância do centro da fóvea, nas regiões nasais e temporais. Dados de EDI-OCT e ERG foram analisados e as correlações do CT com a acuidade visual melhor corrigida (BCVA) e da espessura foveal central (CFT) foram realizadas. Resultados: As CTs subfoveais médias nos grupos CD e controle foram 240,70 ± 70,78 μm e 356,18 ± 48,55 μm, respectivamente. A CT subfoveal foi significativamente mais fina em pacientes com CD do que nos controles (p<0,001). Os com CD pacientes apresentaram também coroides significativamente mais finas do que os controles, em cada local de medição em relação à fóvea (p<0,001). A CT subfoveal no grupo CD se correlacionou com o CFT (p=0,012), mas nenhuma correlação significativa foi encontrada entre a CT subfoveal e a acuidade visual ou respostas fotópicas da ERG. Conclusões: O presente estudo demonstrou um afinamento significativo da coroide em pacientes com CD. A EDI-OCT é uma técnica útil para descrever as mudanças que ocorrem na coroide de pacientes com CD. Futuros estudos investigando a associação entre as alterações da coroide e a destruição da retina externa ou estágio da doença irão proporcionar uma melhor compreensão da fisiopatologia da CD.

Establishment of a transgenic zebrafish line with tdTomato expression in the ultraviolet-sensitive cone photoreceptors / 中国实验动物学报

Objective To better understand the mechanisms of cone opsin transport , we set to generate a trans-genic zebrafish line with red fluorescence proteins expressing in the cone photoreceptors .Methods We used sws1 promot-er to drive the expression of a chimerical protein , in which the last 44 amino acids of rhodopsin of Xenopus laevis were fused to the C-terminus of tdTomato to restrict its localization to the outer segment of photoreceptors .Results We successfully i-solated such a transgenic zebrafish line and confirmed the localization of tdTomato by immunostaining analysis .Conclu-sions This transgenic zebrafish line will help us to better understand the transport mechanisms of cone opsins , especially the transport in live photoreceptors .

Cyclic nucleotide-gated channels and retinal cone photoreceptor cells function / 中华实验眼科杂志

Cyclic nucleotide-gated (CNG) channels are ion channels which are activated by the binding of cyclic guanosine monophosphate (cGMP) or cyclic adenosine monophosphate (cAMP),they play a central role in the signal transduction pathways of vision and olfaction.Six different genes encode CNG protein,containing four A subunits (A1-A4) and two B subunits (B1 and B3).CNGA3 and CNGB3 have been found to be implicated in achromatopsia-associated mutations.Recently,a huge amount of researches showed the good responses to gene therapy in achromatopsia animal models.This article briefly reviewed the physiological roles of CNG channel in retinal cone photoreceptor cells and the recent research achievements of gene therapy in CNG channel-deficient mouse models with achromatopsia.

Enzyme Histochemical Identification of a Subtype of Cone Photoreceptor in the Mammalian Retina

PURPOSE: To identify a subtype of cone photoreceptor in the mammalian retina using enzyme histochemical method. METHODS: In human, rabbits and cats, identification of cone photoreceptor was tried with carbonic anhydrase after retinal tissue isolation and section. RESULTS: In human, subtype of cone photoreceptor was identified. In rabbits, one type of carbonic anhydrase negative regular cell was detected and suspected as rod cells. In cats, only blue cone cell and rod cell were detected and no red-green cone cell was detected. CONCLUSIONS: In cats and rabbits, identification of red-green cone cell and blue cone cell was difficult. So, enzyme histochemical identification of cone photoreceptor using carbonic anhydrase need more research to imply in mammalian retina.