Functional Analysis and Immunochemical Analyses of Ca2+ Homeostasis-related Proteins Expression of Glaucoma-induced Retinal Degeneration in Rats

이지연,오수자 한국뇌신경과학회 2018 Experimental Neurobiology Vol.27 No.1

The retinal degeneration resulting from elevated intraocular pressure was evaluated through functional and morphological analyses, for better understanding of the pathophysiology of glaucoma. Ocular hypertension was induced via unilateral episcleral venous cauterization in rats. Experimental time was set at 1 and 3 days, and 1, 2, 4, and 8 weeks post-operation. Retinal function was analyzed using electroretinography. For morphological analysis, retinal tissues were processed for immunochemistry by using antibodies against the calcium-sensing receptor and calcium-binding proteins. Apoptosis was analyzed using the TUNEL method and electron microscopy. Amplitudes of a- and b-wave in scotopic and photopic responses were found to be reduced in all glaucomatous retinas. Photopic negative response for ganglion cell function significantly reduced from 1-day and more significantly reduced in 2-week glaucoma. Calcium-sensing receptor immunoreactivity in ganglion cells remarkably reduced at 8 weeks; conversely, protein amounts increased significantly. Calcium-binding proteins immunoreactivity in amacrine cells clearly reduced at 8 weeks, despite of uneven changes in protein amounts. Apoptosis appeared in both photoreceptors and ganglion cells in 8-week glaucomatous retina. Apoptotic feature of photoreceptors was typical, whereas that of ganglion cells was necrotic in nature. These findings suggest that elevated intraocular pressure affects the sensitivity of photoreceptors and retinal ganglion cells, and leads to apoptotic death. The calciumsensing receptor may be a useful detector for alteration of extracellular calcium levels surrounding the ganglion cells.

Ocular biometry of Seoul National University (SNU) miniature pig

Ha young Jang,Seok Jae Lee,Eun Gyeong Yoon,Seong Yong Cho,Dong Hyun Jo,Jeong Hwan Che,Byeong-Cheol Kang,Jeong Hun Kim 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7

The pig eye is similar to the human eye in size and structure, containing a cone photoreceptor-dominant visual streak. It makes pigs an important animal species for ocular biomedical studies, including evaluating the safety and efficacy of ocular therapeutics, novel biomaterials, surgical procedures, and implantable materials or devices utilizing advanced in vivo diagnostic techniques. Seoul National University (SNU) miniature pigs (mini-pig) are an important animal resource of Seoul National University Biomedical Center for Animal Resource and Development (BCARD) and are actively used in organ transplantation research. However, further studies on other characteristics were required to be used in various biomedical investigations. Thus ophthalmic features of 6 to 10-month-old three male SNU mini-pigs were characterized using diagnostic modalities including intraocular pressure (IOP) measurement, ultrasonography, fundoscopic imaging, fluorescein angiography (FA), and electroretinography. Mean IOP was 16.47±0.73 mmHg. The optic disc has sharp margins and is normal in color, with a small central cup. Arterioles and venules have normal color and sheen, starting from the center of the disc. There were no abnormalities of FA images such as hyper- or hypo fluorescence and any delay in filling. The amplitudes (μV) of the rod response, mixed rod-cone response, and cone response were 81.73±5.49, 254.60±9.63, and 102.25±9.99. We performed this study as a beginning point to provide the possibility that SNU mini-pig may become a useful animal species for ophthalmological research and to establish the normative reference through the characterization of SNU mini-pig using diagnostic modalities.

전체시야망막전위도에서 무반응인 망막색소상피변성의 다국소망막전위도

장선영,임상현,온영훈 대한안과학회 2009 대한안과학회지 Vol.50 No.12

Purpose: To investigate the clinical potential of multifocal electroretinography (mf-ERG) for the evaluation of residual retinal function in retinitis pigmentosa (RP). Methods: From a group of 41 patients with RP examined for full-field and mf-ERGs, 24 patients were selected in whom the full-field ERGs were non-detectable. Data from the mf-ERGs of this group were reviewed retrospectively. Patients were divided into two groups based on best corrected visual acuity (BCVA); Group A, with a BCVA of less than 0.5, and group B with a BCVA greater than 0.5. The amplitudes and implicit times of Ring 1 and Ring 2 among six concentric rings were measured for comparison between mf-ERG groups. Results: In the mf-ERGs, the amplitudes of Ring 1 and Ring 2 were reduced and implicit time was delayed in all 48 eyes of 24 patients in whom scotopic and photopic responses were non-detectable in full-field ERGs, whereas, there were no detectable responses in Rings 3 thru 6. There was a greater reduction in amplitude and an increased delay in implicit time in group A. Conclusions: The mf-ERG can estimate the residual macular function in a group of patients with RP in whom the full-field ERG is non-recordable. 목적: 망막색소상피변성의 망막기능 평가에 대한 다국소망막전위도의 유용성을 알아보고자 하였다. 대상과 방법: 망막색소상피변성을 진단받은 환자 41명 중 전체시야망막전위도에서 무반응으로 기록된 24명(48안)을 대상으로 후향적 으로 조사하였다. 다국소망막전위도의 Ring 1과 Ring 2 반응의 진폭 및 정점잠시의 평균을 구하여 정상 대조군과 비교하였으며 대상안 의 최대교정시력에 따라 0.5 미만군(Group A), 0.5 이상군(Group B)으로 분류하여 반응의 차이가 있는지를 알아보았다. 결과: 전체시야망막전위도상 반응 망막전위가 10 μV 이하로 무반응이 관찰된 24명(48안) 모두 다국소망막전위도의 Ring 1과 Ring 2에서 반응이 관찰되었으며 정상 대조군과 비교하여 진폭이 감소되어 있고 정점잠시가 연장되어 있었다. Ring 3~6에서는 반응이 관 찰되지 않았다. 대상안에 따른 비교에서 시력이 상대적으로 저하된 군에서 통계학적으로 의미 있는 진폭의 감소 및 정점잠시의 연장이 관찰되었다(p<0.05). 결론: 망막색소상피변성에서 전체시야망막전위도가 무반응으로 기록되어 망막기능의 평가가 불가능한 경우에도 다국소망막전위도는 잔존해있는 황반부의 기능을 평가할 수 있다.

Electroretinography recordings using a light emitting diode active corneal electrode in healthy beagle dogs

Yoshiki Itoh,Yasuharu Izumisawa,Seiya Maehara,Kazuto Yamashita,Norihiko Itoh 대한수의학회 2013 Journal of Veterinary Science Vol.14 No.1

Electroretinography (ERG) is a well-established diagnostic procedure for objectively evaluating retinal function. In this study, ERG in beagle dogs, which are a popular experimental animal, was performed to determine the normal range of ERG variables and assess differences between the left and right eyes. ERG findings including rod, combined rod-cone,single-flash cone, and 30-Hz flicker responses were recorded with an LED-electrode in 43 sedated beagle dogs. The subjects were divided into young (< 1 year old), adult (1∼5years old), and senile animals (≥ 6 years old). Normal ERG ranges were obtained. Significant differences in b-wave amplitude along with b/a ratio of the combined rod-cone response were found between the young and adult animals as well as young and senile dogs. No significant differences were observed between the left and right eyes. ERG variables in beagle dogs differed by age due to age-related retinal changes. Thus, we propose that normal ERG ranges should be determined according to age in each clinic and laboratory using its own equipment because each institution usually has different systems or protocols for ERG testing.

Blue-on-Green Flash Induces Maximal Photopic Negative Response and Oscillatory Potential and Serves as a Diagnostic Marker for Glaucoma in Rat Retina

박수진,백선숙,이지연,오수자,김인범 한국뇌신경과학회 2018 Experimental Neurobiology Vol.27 No.3

The purpose of this study was to investigate the application of various electroretinography (ERG) to the diagnosis of inner retinal dysfunction induced by mild intraocular pressure (IOP) elevation in a rat glaucoma model. For inner retinal function measurements, available photopic ERG protocols were applied under various light conditions including monochromatic combinations, which complement conventional scotopic ERG. Three episcleral veins in the right eyes of Sprague-Dawley rats were cauterized to induce an experimental model of glaucoma, leading to mild IOP elevation. ERG responses were measured before surgery and at 1, 2, 4, and 8 weeks after cauterization. We first confirmed that the amplitude reduction in the standard photopic b-wave was almost comparable to the amplitudes of scotopic a- and b-waves in glaucomatous eyes over time. We have implemented additional photopic ERG protocols under different stimulus conditions, which consisted of a longer duration and different monochromatic combinations. Such a change in the stimulations resulted in more pronounced differences in response between the two groups. Especially in normal animals, blue stimulation on a green background produced the largest b-wave and photopic negative response (PhNR) amplitudes and caused more pronounced oscillatory potential (OP) wavelets (individual components). In glaucomatous eyes, blue stimulation on a green background significantly reduced PhNR amplitudes and abolished the robust OP components. These results, by providing the usefulness of blue on green combination, suggest the applicable photopic ERG protocol that complements the conventional ERG methods of accessing the progression of glaucomatous damage in the rat retina.

요오드 아세트산으로 유도된 성묘 망막변성 모델에서의 망막전위도 변화

김창주,이명신,이승욱,이상준 대한안과학회 2019 대한안과학회지 Vol.60 No.12

Purpose: We explored changes in photoreceptor function and histology in an iodoacetic acid (IAA)-induced model of feline retinal degeneration. Methods: From January to October 2014, we studied 11 adult felines (22 eyes) over 2 years of age divided into two groups (two in a control and nine in an IAA group). The mean body weights of these two groups were 1.75 ± 0.35 and 1.61 ± 0.19 kg, and the male:female sex ratios 1:1 and 2:7, respectively. Electroretinograms (ERGs) were obtained before injection and at 1-4 week post-injection (20 mg/kg IAA). Standard paraffin retinal sections were stained with hematoxylin/eosin and other sections subjected to immunohistochemistry. We histologically evaluated the outer nuclear layer, and photoreceptor cone and rod cells. Results: In ERGs of the IAA group, both the rod and cone mean b wave amplitudes decreased significantly from week 1 to week 4 after injection (27.43, 29.41, 64.17, and 56.03; and 61.04, 51.25, 131.36, and 136.68 μV, respectively) compared to baseline (322.48 and 610.00 μV respectively) (p < 0.01). Optical microscopy revealed a significant decrease in the cell count of the outer nuclear retinal layer (16.83 ± 0.89 in the control and 11.98 ± 3.55 in the IAA groups, p < 0.01). Fluorescence microscopy revealed a significant reduction in the mean area per unit length of the rod cell layer (35,225.67 ± 2,477.02 and 14,903.62 ± 2,319.65 in the control and IAA groups, p < 0.01), but not in the cone cell count (26.16 ± 1.34 and 23.98 ± 6.16 in the control and IAA groups, p = 0.075). Conclusions: ERGs revealed that functional b wave amplitudes fell after IAA-induce retinal degeneration in felines; histology showed that this was accompanied by reductions in the numbers of outer nuclear layers and rod cells. IAA induces photoreceptor degeneration in felines; further study is necessary. 목적: 요오드 아세트산(Iodoacetic acid, IAA)을 이용하여 성묘 망막변성을 일으키고, 기능적, 조직학적 광수용체 변성을 확인한다. 대상과 방법: 2014년 1월부터 10월까지 2세 이상의 성묘 11마리(22안)를 대상으로 하였다(대조군 2마리, 실험군 9마리). 평균 체중은 대조군, 실험군에서 각각 1.75 ± 0.35, 1.61 ± 0.19 kg, 성별은 수컷:암컷이 1:1, 2:7이었다. 주사(IAA 20 mg/kg) 전후 1주 간격으로 4회 망막전위도(electroretinogram, ERG)를 시행하였다. 파라핀 절편 제작 후 hematoxylin-eosin (HE), immunohistochemistry (IHC) 염색을 하고, 외과립층, 원추세포, 막대세포를 관찰하였다. 결과: 실험군에서 ERG 검사상 암반응과 명반응의 b wave 평균 진폭이 주사 전에 비해 주사 후 1주부터 4주까지 모두 유의하게 낮았다(p<0.01). 외과립층 세포핵의 개수는 실험군에서 유의하게 줄었고(p<0.01), 단위 길이당 염색된 막대세포층의 면적도 실험군에서 유의하게 감소했다(p<0.01). 그렇지만 원추세포의 개수는 유의한 감소가 없었다(p=0.075). 결론: IAA 20 mg/kg를 투여한 성묘는 기능적으로 ERG의 b wave 진폭의 감소, 조직학적으로 외과립층과 막대세포의 감소를 보였다. IAA 유발 성묘 모델은 광수용체변성의 모델로 추후 관련 연구에 사용될 수 있을 것이다.

미숙아망막병증이 없는 미숙아에서 RETevalTM을 이용한 망막전위도 평가

정경도,박재용,박지민,김재석,최 진,황제형 한국망막학회 2022 Journal of Retina Vol.7 No.2

Purpose: This study was to conducted to evaluate the usefulness of light adapted electroretinography (ERG) using the RETevalTM system (LKC Technologies, Gaithersburg, MD, USA) in preterm infants without retinopathy of prematurity. Methods: Overall, 18 preterm infants underwent light adapted ERG using the RETevalTM system without sedation. Readable results were acquired from 11 patients (61%) and the mean gestational age at birth was 33 ± 3 weeks. Results: The amplitude and implicit time of the ‘a’ wave was -8.1 ± 6.6 μV and 17.3 ± 7.8 ms, respectively, while those of the ‘b’ wave was 20.4 ± 13.6 μV and 36.7 ± 8.8 ms, respectively. Additionally, 30-Hz flicker results were obtained with an amplitude and implicit time of 6.0 ± 3.8 μV and 32.3 ± 2.8 ms, respectively. Negative correlation was found between the ‘a’ wave amplitude and age at examination (p < 0.05). The light-adapted 3.0 ERG response was decreased in preterm infants and a larger decrease in ‘b’ wave amplitude than ‘a’ wave amplitude was observed, which corresponds to the histological maturation of the retina. Conclusions: Our study indicates that RETevalTM system is useful for evaluating retinal function in preterm infants.

Mon–Pack 3로 측정한 정상인의 전기 생리학적 검사 결과

민성규,이영훈,진선영.Seong Gyu Min. MD. Young Hoon Lee. MD. Sun Young Jin. MD 대한안과학회 2014 대한안과학회지 Vol.55 No.11

Purpose: We present the results of visual evoked potential (VEP), electroretinography (ERG), and electrooculography (EOG) in normal subjects using the Mon-pack 3 system (Metrovision). Methods: VEP, ERG, and EOG were obtained in 92 normal eyes. The measurements followed the International Society for Clinical Electrophysiology of Vision (ISCEV) standardization protocol. In VEP, the standard electrode was placed on the forehead and the active electrode was attached on the occiput. In ERG, a 20-minute dark adaptation was performed after mydriasis, and an ERG-jet electrode was used. EOG was measured by attaching an electrode to each medial canthal skin. Each latent period and electric potential was measured with average, standard deviation, median, and 95% confidencenterval (95% CI). Results: The mean P100 latency in pattern VEP was 104.36 ms, and P100 latency in flash VEP was 116.71 ms. For the maximal ERG response, the implicit times of a and b waves were 22.65 ms and 44.58 ms, respectively and the amplitude of a and b waves were 274.09 μv and 489.52 μv, respectively. For the ERG cone response, the implicit time of a and b waves were 18.21 ms and 33.40 ms, respectively, and the amplitude of a and b waves were 35.87 μv and 104.42 μv, respectively. The mean ERG oscillitatory potential was 285.53 μv. The average EOG Arden ratio was 2.54. Conclusions: VEP, ERG, and EOG results from normal subjects using the Mon-pack 3 system can be applied to the diagnosis of retina and optic nerve disease and basic research. J Korean Ophthalmol Soc 2014;55(11):1693-1697

황반박리가 동반된 열공망막박리의 재유착 후 황반부의 다국소 망막전위도 소견

안정현,장무환,경성은,Jung Hyun Ahn,M,D,Moo Hwan Chang,M,D,Seong Eun Kyung,M,D 대한안과학회 2008 대한안과학회지 Vol.49 No.3

`Purpose: To assess macular function by multifocal electroretinography after reattachment of macula-off retinal detachment and to evaluate relationship between duration of macular detachment (DMD) and functional recovery. Methods: Nineteen patients (19 eyes) with macula-off rhegmatogenous retinal detachment underwent pneumatic retinopexy or scleral buckling. Retinal reattachment was obtained successfully in all patients. Duration of follow-up of all patients is at least more than 12 months. Eyes were divided into 2 groups, corresponding to the DMD : Group A (within 7 days, n=9 eyes), Group B (>7 days, n=10 eyes). The amplitudes and implicit times of N1-wave and P1-wave of mfERGs in Area 1 (Ring 1), Area 2 (Ring 1+2) were compared between Group A and B and between Group A and control group. Results: The P1 amplitudes in Area 1 and 2 were significantly different between Group A and B (P<0.05). N1 amplitudes in Area 1 were significantly different between Group A and B (P<0.05), but no significant difference of P1 amplitudes in Area 2 between Group A and B (P>0.05). There were no significant difference of all data between Group A and control in Area 1 and 2 (P>0.05) The implicit times of N1, P1 were not significantly different between Group A and B. Conclusions: The DMD plays a key role in recovery of visual function after reattachment. The mfERG is a useful tool to evaluate the recovery of macular function after reattachment of macula-off retinal detachments.`

The Effects of Alcohol on Visual Evoked Potential and Multifocal Electroretinography

김지택,윤철민,김성우,오재령,허걸 대한의학회 2016 Journal of Korean medical science Vol.31 No.5

The aim of this study was to investigate the acute effects of ethanol administration on pattern-reversal visual evoked potential (VEP) and multifocal electroretinography (mfERG). Fifteen healthy subjects with no ocular or general disease were recruited. VEP (0.25° pattern sizes) and mfERG with 19 elements in two recording segments were performed before ethanol administration to obtain baseline for each participant. A few days later, the participants visited again for VEP and mfERG measurements after ethanol administration. Ethanol (0.75 g/kg) was administered orally over the course of 30 minutes. VEP and blood alcohol concentration were evaluated one hour after ethanol administration, and mfERG was conducted after pupil dilation. The Wilcoxon signed-rank test was used to compare parameter changes after randomized eye selection. The mean blood alcohol concentration was 0.034% ± 0.05% by volume. VEP revealed a P100 latency delay (109.4 ± 5.3; 113.1 ± 8.2; P = 0.008) after alcohol administration. The P1 implicit time of ring 1 on mfERG showed a trend of shortening after alcohol administration (37.9 ± 1.0; 37.2 ± 1.5; P = 0.048). However, the changes did not show statistical significance after Bonferroni correction. In conclusion, orally administrated ethanol (0.75 g/kg) appears to suppress the central nervous system, but it is not clear whether alcohol intake affects the retina.