Characterizing the Retinal Function of<i>Psammomys obesus</i>: A Diurnal Rodent Model to Study Human Retinal Function

Dellaa, Ahmed; Polosa, Anna; Mbarek, Sihem; Hammoum, Imane; Messaoud, R.; Amara, Soumaya; Azaiz, Rached; Charfeddine, Ridha; Dogui, Mohamed; Khairallah, Moncef; Lachapelle, Pierre; Chaouacha‐Chekir, Rafika Ben

doi:10.3109/02713683.2016.1141963

Cited by 9 publications

(15 citation statements)

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“…ERGs were recorded using a Metrovision system (France) following 15 days, 1, 2, 3, 4, 5, 6, and 7 months after the onset of diabetes according to a method previously described by us (Dellaa et al, 2016; Dellaa et al, 2018). The animals were anesthetized with an intraperitoneal injection of ketamine (120 mg/kg), the pupils dilated with tropicamide (25 mg/5 ml; UNIMED, Tunisia) and the cornea anesthetized with eye drops of 0.5% Alcaine (Bausch & Lomb, France).…”

Section: Methodsmentioning

confidence: 99%

Functional alterations of retinal neurons and vascular involvement progress simultaneously in the Psammomys obesus model of diabetic retinopathy

Dellaa¹,

Mbarek²,

Kahloun

et al. 2021

J Comp Neurol

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To investigate the progression of diabetic retinopathy (DR) in a new diurnal animal model, we monitored clinically the DR in Psammomys obesus (P. obesus) during 7 months using electroretinography (ERG) and imaging techniques. After the onset of DR, all ERG components decreased progressively. In scotopic conditions, by 3‐months of disease progression, the diabetic P. obesus displayed a significant decrease in amplitude of b‐max, b‐wave responses, and mixed b‐waves. While mixed a‐wave decreased between 4 and 7 months. Significant differences of OP2 appeared following 1 month of disease. In photopic conditions, we noticed a decrease in the a‐wave at 2 months, while it took more than 5 months in b‐wave amplitude. The photopic negative response (PhNR) and the i‐wave amplitudes decreased following 4 and 5 months. OP1 and OP2 were the first to be altered and a significant decrease in the amplitude started after 3 months. Finally, 30 Hz‐flicker and photopic S‐cone were impaired after 2 and 3 months, respectively. The assessment of the eye fundus of the retina revealed an abnormal vascular architecture appeared at Months 6 and 7. In addition, we noticed exudates in the superior periphery of the retina at the same stage. The retina thickness showed a significant reduction at Month 7. Our results indicate that the clinical correlates of human DR are present in diabetic P. obesus. The depressed of ERGs, disruption of retinal architecture, and the appearance of exudates may reflect vascular and neuronal damage throughout the retina as are seen in the advanced stages of human DR.

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Section: Methodsmentioning

confidence: 99%

Functional alterations of retinal neurons and vascular involvement progress simultaneously in the Psammomys obesus model of diabetic retinopathy

Dellaa¹,

Mbarek²,

Kahloun

et al. 2021

J Comp Neurol

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“…Similarly, the electroretinogram of P . obesus also shares several features with that of human subjects [ 29 ], making it a remarkable model to investigate the retinal complications of diet-induced type 2 DR as it meets the criteria listed by the AMDCC [Animal models of diabetic complications consortium ( www.amdcc.org )]. Of interest, in the present study, all P .…”

Section: Discussionmentioning

confidence: 99%

“…Measurements were made as described in our previous study [ 29 ]. Briefly, the visual monitor system (Mon Color, Metrovision) was used for stimulus generation and data acquisition.…”

Section: Methodsmentioning

confidence: 99%

“…Following the scotopic recordings and after 10 minutes of light-adaptation (30 cd.m- 2 background light), photopic (cone-mediated) ERGs were evoked using flashes of white light of 3 3cd.s/m 2 in intensity. Each set of ERG responses was an average of 20 responses evoked at an inter-stimulus interval of 1 second[ 29 ]. A 30-Hz flicker response was also obtained using the same flash intensity and background.…”

Section: Methodsmentioning

confidence: 99%

“…ERG analysis was performed according to the standard practice [ 30 ] as previously reported [ 29 ]. The following ERG parameters were measured: rod-response amplitude (from the baseline to positive peak), a-wave amplitude (baseline to the first negative deflection), b-wave amplitude (a-wave peak to positive b-wave peak), i-wave amplitude (from the trough of the b-wave to the peak of the i-wave), PhNR amplitude (baseline to negative trough following b-wave), 30 Hz flicker amplitude (from the trough to the peak), OPs amplitude (the sum amplitude of wavelets 1–4 measured from the trough to the peak of each response component), S-cone amplitude (the b-wave amplitude of the S-cone response was quantified) and the b/a-wave amplitude ratio.…”

Section: Methodsmentioning

confidence: 99%

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Electroretinographic evidence suggesting that the type 2 diabetic retinopathy of the sand rat Psammomys obesus is comparable to that of humans

et al. 2018

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PurposeType 2 diabetic retinopathy is the main cause of acquired blindness in adults. The aim of this work was to examine the retinal function of the sand rat Psammomys obesus as an animal model of diet-induced type 2 diabetes when subjected to a hypercaloric regimen.Materials and methodsHyperglycemia was induced in Psammomys obesus by high caloric diet (4 kcal/g). The visual function of control (n = 7) and diabetic (n = 7) adult rodents were followed up during 28 consecutive weeks with full-field electroretinogram(ERG) recordings evoked to flashes of white light according to the standard protocol of the International Society for Clinical Electrophysiology of Vision protocol (ISCEV).ResultsTwenty-eight weeks following the induction of diabetes, results revealed significantly reduced and delayed photopic and scotopic ERG responses in diabetic rats compared to control rats. More specifically, we noted a significant decrease in the amplitude of the dark-adapted 0.01ERG (62%), a- and b-wave amplitudes of the dark-adapted 3.0 ERG (33.6%, 55.1%) and the four major oscillatory potentials components (OP1-OP4) (39.0%, 75.2%, 54.8% and 53.7% respectively). In photopic conditions, diabetic rats showed a significant decrease in a- and b-wave (30.4%, 43.4%), photopic negative response (55.3%), 30 Hz flicker (63.7%), OP1-OP4(51.6%, 61.8%, 68.3% and 47.5% respectively) and S-cone (34.7%). Significantly delayed implicit times were observed for all ERG components in the diabetic animals. Results obtained are comparable to those characterizing the retinal function of patients affected with advanced stage of diabetic retinopathy.ConclusionPsammomys obesus is a useful translational model to study the pathophysiology of diabetic retinopathy in order to explore new therapeutic avenues in human patients.

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Astaxanthin inhibits aldose reductase activity in Psammomys obesus, a model of type 2 diabetes and diabetic retinopathy

Khedher¹,

Hajri²,

Dellaa³

et al. 2019

Food Science & Nutrition

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Astaxanthin (ATX) is a marine carotenoid known for its powerful antioxidant and neuroprotective properties. In this study, we investigated the in vitro and in vivo potential inhibitory effect of ATX on the aldose reductase (AR) activity, a key enzyme in the polyol pathway responsible for the pathogenesis of diabetic complications including diabetic retinopathy (DR). The gerbil Psammomys obesus (P. ob.), an animal model for type 2 diabetes and DR has been used. The erythrocyte and retinal AR activity of P. ob. individuals were, respectively, assessed monthly and at the 7th month during a 7‐month hypercaloric diet (HD) using a NADPH oxidation method. Meanwhile, the body weight and blood glucose of the gerbils were monitored. After 7 months, P. ob. individuals were fed with ATX (4.8 mg/kg of body weight) once a day for 1 week. The results showed that the HD‐fed animals developed significant obesity and hyperglycemia in comparison with controls. Erythrocyte AR activity showed a progressive and significant increase in the HD‐fed group compared with controls. Retinal AR activity was higher in the 7‐month HD‐fed group compared with controls. Erythrocyte AR activity was markedly decreased after ATX‐treatment in vitro and in vivo. These findings suggested that ATX inhibited the erythrocyte AR activity and could be used for DR prevention and/or early treatment.

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Characterizing the Retinal Function ofPsammomys obesus: A Diurnal Rodent Model to Study Human Retinal Function

Cited by 9 publications

References 44 publications

Functional alterations of retinal neurons and vascular involvement progress simultaneously in the Psammomys obesus model of diabetic retinopathy

Functional alterations of retinal neurons and vascular involvement progress simultaneously in the Psammomys obesus model of diabetic retinopathy

Electroretinographic evidence suggesting that the type 2 diabetic retinopathy of the sand rat Psammomys obesus is comparable to that of humans

Astaxanthin inhibits aldose reductase activity in Psammomys obesus, a model of type 2 diabetes and diabetic retinopathy

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