Persistent functional and structural retinal anomalies in newborn rats exposed to hyperoxia

1999 ◽  
Vol 77 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Pierre Lachapelle ◽  
Olga Dembinska ◽  
Luz Marina Rojas ◽  
Julie Benoit ◽  
Guillermina Almazan ◽  
...  
Keyword(s):  
Structural Modification ◽  
Histological Analysis ◽  
Plexiform Layer ◽  
Oscillatory Potentials ◽  
Newborn Rats ◽  
Sprague Dawley ◽  
Structural Modifications ◽  
Retina Development ◽  
Sprague Dawley Rats ◽  
Retinal Disorder

Previous studies have shown that newborn rats exposed postnatally to hyperoxia will develop a permanent impairment of the retinal function as determined with the electroretinogram (ERG). The purpose of our study was to examine whether postnatal hyperoxia equally alters the light- and dark-adapted ERGs and oscillatory potentials (OPs) as well as leads to permanent structural modification of the retina. During the first 14 days of life, cohorts of Sprague-Dawley rats were exposed to a hyperoxic environment, and ERGs were recorded at mean ages of approximately 25 and 55 days. Our results indicate that both light- and dark-adapted ERGs and OPs are already significantly altered within a few days following exposure to hyperoxia. None of the ERG and (or) OP parameters, with the exception of the a-wave, returned to normal values by 55 days of age. In fact some dark-adapted OPs were completely abolished following postnatal O2 exposure. Histological analysis revealed that the retina of rats exposed to hyperoxia failed to develop an outer plexiform layer and had a reduced count of horizontal cells, consistent with the permanent postreceptoral anomalies seen in the ERG responses. Our results suggest that postnatal hyperoxia causes a generalized retinal disorder leading to permanent structural modifications of the retinal cytoarchitecture and lasting anomalies of the rod and cone functions.Key words: rods, cones, electroretinography, oscillatory potentials, hyperoxia, retina, development.

Histological analysis of different local haemostatic agents used for periapical surgery: An experimental study with Sprague‐Dawley rats

2019 ◽  
Vol 45 (3) ◽  
pp. 357-364
Author(s):  
Jesús Mena‐Álvarez ◽  
Norberto Quispe‐López ◽  
Álvaro Zubizarreta‐Macho ◽  
Cristina Rico‐Romano ◽  
Rosa Rodero‐Villanueva ◽  
...  
Keyword(s):  
Experimental Study ◽  
Histological Analysis ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Haemostatic Agents

scholarly journals Diabetes increases brain damage caused by severe hypoglycemia

2009 ◽  
Vol 297 (1) ◽  
pp. E194-E201 ◽  
Author(s):  
Adam J. Bree ◽  
Erwin C. Puente ◽  
Dorit Daphna-Iken ◽  
Simon J. Fisher
Keyword(s):  
Brain Damage ◽  
Histological Analysis ◽  
Neuronal Damage ◽  
Severe Hypoglycemia ◽  
Hippocampal Damage ◽  
Sprague Dawley ◽  
Brain Areas ◽  
Sprague Dawley Rats ◽  
Brain Tissue Damage ◽  
Extent Of Damage

Insulin-induced severe hypoglycemia causes brain damage. The hypothesis to be tested was that diabetes portends to more extensive brain tissue damage following an episode of severe hypoglycemia. Nine-week-old male streptozotocin-diabetic (DIAB; n = 10) or vehicle-injected control (CONT; n = 7) Sprague-Dawley rats were subjected to hyperinsulinemic (0.2 U·kg−1·min−1) severe hypoglycemic (10–15 mg/dl) clamps while awake and unrestrained. Groups were precisely matched for depth and duration (1 h) of severe hypoglycemia (CONT 11 ± 0.5 and DIAB 12 ± 0.2 mg/dl, P = not significant). During severe hypoglycemia, an equal number of episodes of seizure-like activity were noted in both groups. One week later, histological analysis demonstrated extensive neuronal damage in regions of the hippocampus, especially in the dentate gyrus and CA1 regions and less so in the CA3 region ( P < 0.05), although total hippocampal damage was not different between groups. However, in the cortex, DIAB rats had significantly (2.3-fold) more dead neurons than CONT rats ( P < 0.05). There was a strong correlation between neuronal damage and the occurrence of seizure-like activity ( r2 > 0.9). Separate studies conducted in groups of diabetic ( n = 5) and nondiabetic ( n = 5) rats not exposed to severe hypoglycemia showed no brain damage. In summary, under the conditions studied, severe hypoglycemia causes brain damage in the cortex and regions within the hippocampus, and the extent of damage is closely correlated to the presence of seizure-like activity in nonanesthetized rats. It is concluded that, in response to insulin-induced severe hypoglycemia, diabetes uniquely increases the vulnerability of specific brain areas to neuronal damage.

Histological analysis of the effects of cadmium, chromium and mercury alone and in combination on the spleen of male Sprague-Dawley rats

2020 ◽  
Vol 55 (8) ◽  
pp. 925-934
Author(s):  
Chantelle Venter ◽  
Anel Olivier ◽  
Helena Taute ◽  
Hester M. Oberholzer
Keyword(s):  
Histological Analysis ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

Spontaneous glomerular immunoglobulin deposition in young Sprague-Dawley rats

1988 ◽  
Vol 22 (4) ◽  
pp. 287-292 ◽  
Author(s):  
N. P. Goode ◽  
A. M. Davison ◽  
G. Gowland ◽  
M. Shires
Keyword(s):  
Immune Complexes ◽  
Age Group ◽  
Newborn Rats ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Weanling Rats ◽  
Dense Deposits ◽  
High Concentrations ◽  
Igm Deposits ◽  
Maternal Igg

The frequency, age-onset and distribution of spontaneously deposited immunoglobulins (lgs) in glomeruli of Sprague-Dawley rats has been investigated. Groups of rats ( n=10) were examined at 4-7 day intervals from birth (presuckling) until 30 days of age. Findings were compared with circulating immunoglobulin concentrations in each age group. Immunoglobulins were undetectable in immature kidneys of newborn rats. However, as early as 5 days, scanty IgA and IgM deposits were observed predominantly in mesangial areas of mature glomeruli, corresponding to low circulating concentrations of these immunoglobulins. By contrast, glomerular IgG deposits were not observed until 21 days, despite relatively high concentrations of circulating maternal IgG from birth. Mesangial deposition of immunoglobulins increased with age. Absence of complement C3c or electron dense deposits associated with this mesangial localization suggests that immunoglobulins were not deposited as immune complexes. Accumulation of non-phlogogenic immunoglobulins in the mesangium of normal rats supports the concept that the mesangium is constantly perfused by circulating macro-molecules and filtration residues. The results indicate problems of interpretation of the significance of endogenous immunoglobulin deposition in models of experimental glomerulonephritis, even in studies involving weanling rats.

scholarly journals Optimization of Complete Rat Heart Decellularization Using Artificial Neural Networks

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 79
Author(s):  
Greta Ionela Barbulescu ◽  
Taddeus Paul Buica ◽  
Iacob Daniel Goje ◽  
Florina Maria Bojin ◽  
Valentin Laurentiu Ordodi ◽  
...  
Keyword(s):  
Neural Networks ◽  
Histological Analysis ◽  
Sodium Dodecyl ◽  
Sprague Dawley ◽  
Deep Convolutional Neural Networks ◽  
Software Application ◽  
Sprague Dawley Rats ◽  
Machine Learning Approach ◽  
Image Set ◽  
Exact Moment

Whole organ decellularization techniques have facilitated the fabrication of extracellular matrices (ECMs) for engineering new organs. Unfortunately, there is no objective gold standard evaluation of the scaffold without applying a destructive method such as histological analysis or DNA removal quantification of the dry tissue. Our proposal is a software application using deep convolutional neural networks (DCNN) to distinguish between different stages of decellularization, determining the exact moment of completion. Hearts from male Sprague Dawley rats (n = 10) were decellularized using 1% sodium dodecyl sulfate (SDS) in a modified Langendorff device in the presence of an alternating rectangular electric field. Spectrophotometric measurements of deoxyribonucleic acid (DNA) and total proteins concentration from the decellularization solution were taken every 30 min. A monitoring system supervised the sessions, collecting a large number of photos saved in corresponding folders. This system aimed to prove a strong correlation between the data gathered by spectrophotometry and the state of the heart that could be visualized with an OpenCV-based spectrometer. A decellularization completion metric was built using a DCNN based classifier model trained using an image set comprising thousands of photos. Optimizing the decellularization process using a machine learning approach launches exponential progress in tissue bioengineering research.

Retinal A2A and A3 adenosine receptors modulate the components of the rat electroretinogram

2017 ◽  
Vol 34 ◽  
Author(s):  
GUDMUNDUR JONSSON ◽  
THOR EYSTEINSSON
Keyword(s):  
Adenosine Receptors ◽  
Mean Amplitude ◽  
Oscillatory Potentials ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Single Flash ◽  
The Central Nervous System ◽  
Photopic Erg ◽  
The Mean

AbstractAdenosine is a neuromodulator present in various areas of the central nervous system, including the retina. Adenosine may serve a neuroprotective role in the retina, based on electroretinogram (ERG) recordings from the rat retina. Our purpose was to assess the role of A2A and A3 adenosine receptors in the generation and modulation of the rat ERG. The flash ERG was recorded with corneal electrodes from Sprague Dawley rats. Agonists and antagonists for A2A and A3 receptors, and adenosine were injected (5 µl) into the vitreous. The effects on the components of the single flash scotopic and photopic ERGs were examined, and ERG flicker. Adenosine (0.5 mM) increased the mean amplitudes of the scotopic ERG a-waves (68 ± 8 to 97 ± 14 µV, P = 0.042), and b-waves (236 ± 38 µV to 305 ± 42 µV). A2A agonist CGS21680 (2 mM) reduced the mean amplitude of the ERG b-wave, from 298 ± 21 µV in response to the brightest stimulus to 212 ± 19 µV (P = 0.005), and mean scotopic oscillatory potentials (OPs) from 100 ± 9 µV to 47 ± 11 µV (P = 0.023). ZM241385 [4 mM], an A2A antagonist, decreased the scotopic b-wave of the ERG. A3 agonist 2-CI-IB-MECA (0.5 mM) increased the a-wave, while decreasing the scotopic and photopic ERG b-waves, and the scotopic OPs. A3 antagonist VUF5574 (1 mM) increased the mean amplitude of the scotopic a-wave (66 ± 8 to 140 ± 29 µV, P = 0.046) and b-wave (224 ± 20 to 312 ± 39 µV, P = 0.0037). No significant effects on ERG flicker were found. We conclude that retinal neurons containing A2A and/or A3 adenosine receptors contribute to the generation of the ERG a- and b-waves and OPs.

scholarly journals The Intoxication Effects of Methanol and Formic Acid on Rat Retina Function

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Dong-Mei Liu ◽  
Shu Zhou ◽  
Jie-Min Chen ◽  
Shu-Ya Peng ◽  
Wen-Tao Xia
Keyword(s):  
Formic Acid ◽  
Oscillatory Potentials ◽  
Control Group ◽  
Sprague Dawley ◽  
Rat Retina ◽  
Elapsed Time ◽  
Sprague Dawley Rats ◽  
Photopic Erg ◽  
Group B ◽  
Retinal Functions

Objective. To explore the potential effects of methanol and its metabolite, formic acid, on rat retina function.Methods. Sprague-Dawley rats were divided into 3- and 7-day groups and a control. Experimental groups were given methanol and the control group were provided saline by gavage. Retinal function of each group was assessed by electroretinogram. Concentrations of methanol and formic acid were detected by GC/HS and HPLC, respectively.Results. The a and b amplitudes of methanol treated groups decreased and latent periods delayed in scotopic and photopic ERG recordings. The summed amplitudes of oscillatory potentials (OPs) of groups B and C decreased and the elapsed time delayed. The amplitudes of OS1, OS3, OS4, and OS5 of group B and OS3, OS4, and OS5 of group C decreased compared with the control group. The IPI1 of group B and IPI1-4 of group C were broader compared with the control group and the IPI1-4 and ET of group B were broader than group C. Conclusions. Both of scotopic and photopic retinal functions were impaired by methanol poisoning, and impairment was more serious in the 7-day than in the 3-day group. OPs, especially later OPs and IPI2, were more sensitive to methanol intoxication than other eletroretinogram subcomponents.

Abstract 262: A Rat Model of Heart Failure With Preserved Ejection Fraction Induced by Pressure Overload

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Shu-Yu Sun ◽  
Barry Campbell ◽  
Valdeci Da Cunha ◽  
Xuening Hong ◽  
Chin-hu Huang ◽  
...  
Keyword(s):  
Histological Analysis ◽  
Potential Model ◽  
Pressure Overload ◽  
Preserved Ejection Fraction ◽  
Sprague Dawley ◽  
Aortic Banding ◽  
Clinical Phenotypes ◽  
Novel Treatments ◽  
Sprague Dawley Rats ◽  
Invasive Hemodynamics

The absence of animal models displaying clinical phenotypes of HFpEF represents a challenge to the pharmaceutical industry in the hope of identifying novel treatments that would benefit patients with this syndrome. We, at Merck, examined the supracoronary aortic banding (SAB) in rats as a potential model and set out to characterize its phenotypes. Juvenile Sprague-Dawley rats were used; a hemostatic clip with an opening of 0.7 mm was placed around the ascending aorta to elicit a pressure overload to the LV. Echocardiography was performed every 3 weeks and invasive hemodynamics was measured at week 9 to evaluate cardiac structural and functional effects; heart and lungs were harvested at the end for morphological and histological analysis. Nine weeks after SAB, LV hypertrophy and dysfunction were apparent, as manifested by increases in LVEDP, left atrial pressure, plasma BNP, LV and lung weights; LV relaxation time constant (Tau) and mitral early to late inflow ratio (E/A) were also increased; while EF and FS were preserved (see table, mean ± SEM). In addition, SAB rats had elevated mean pulmonary pressure (sham 14 ± 1.7 vs. SAB 37 ± 4.4 mm Hg, p<0.05) with an abnormal transpulmonary gradient (sham 12 ± 2.5 vs. SAB 23 ± 0.1 mm Hg, p<0.05), indicating comorbidity of pulmonary hypertension. Finally, piloerection, dyspnea and loss of muscle mass were evident and exercise tolerance measured by treadmill test was decreased in SAB rats. In summary, rats undergoing SAB exhibit many of the clinical phenotypes of HFpEF. Further work includes examining the effects of novel therapies in SAB rats on improving these clinical phenotypes of HFpEF and expanding the model to study morbidity and mortality.

scholarly journals Influence on Bone-to-Implant Contact of Non-Thermal Low-Pressure Argon Plasma: An Experimental Study in Rats

2020 ◽  
Vol 10 (9) ◽  
pp. 3069
Author(s):  
Arturo Sanchez-Perez ◽  
Ana I. Nicolas-Silvente ◽  
Carmen Sanchez-Matas ◽  
Fernando Muñoz-Guzon ◽  
Carlos Navarro-Cuellar ◽  
...  
Keyword(s):  
Essential Role ◽  
Histological Analysis ◽  
Bacterial Colonization ◽  
Argon Plasma ◽  
Low Pressure ◽  
Sprague Dawley ◽  
New Techniques ◽  
Implant Placement ◽  
Sprague Dawley Rats ◽  
Bone To Implant Contact

Roughness characteristics play an essential role in osseointegration. However, there is a concern about the susceptibility of those surfaces to bacterial colonization. New techniques for cleaning and surface treatment have appeared that could favor osseointegration without the need to create surfaces as rough. Such is the case of non-thermal low-pressure argon plasma (NTLP-ArP). One hundred and forty-four implants were placed in the tibiae of 36 Sprague Dawley rats, distributed in four experimental groups: I: mechanized surface; II: mechanized surface treated with NTLP-ArP, III: resorbable blast media (RBM) surface; and IV: RBM surface treated with (NTLP-ArP). Bone-to-implant contact (BIC) percentages were calculated by microtomographic evaluation and histological analysis at one, two, and four weeks after implant placement. ANOVA and Mann–Whitney tests were used for statistical analysis, establishing p < 0.05. No significant differences were found at one-week comparisons. The groups treated with NTLP-ArP obtained higher BIC% than those not treated at two and four weeks. Mechanized surfaces treated with NTLP-ArP obtained BIC values similar to RBM surfaces.

scholarly journals Corticotomy depth and regional acceleratory phenomenon intensity:

2020 ◽  
Author(s):  
Jeremy R. Kernitsky ◽  
Taisuke Ohira ◽  
Dhurata Shosho ◽  
June Lim ◽  
Abdullah Bamashmous ◽  
...  
Keyword(s):  
Histological Analysis ◽  
Cone Beam ◽  
Deep Penetration ◽  
Sprague Dawley ◽  
Collagen Formation ◽  
Sprague Dawley Rats ◽  
Computed Tomography Scans ◽  
Group A ◽  
Regional Acceleratory Phenomenon ◽  
The Right

ABSTRACT Objectives To determine if the depth of corticotomy done with the piezoelectric knife could play a role in the intensity of the regional acceleratory phenomenon (RAP). Materials and Methods Eighteen Sprague-Dawley rats were divided into two groups: untreated (3 rats) and treatment (15 rats). In the treatment group, a split-model design was used. The right tibia received transcortical (deep) penetrations with the piezoelectric knife, while intracortical (shallow) penetrations were performed on the left tibia of the same animal. The rats were euthanized at day 1, 3, 7, 14, and 28. Cone-beam computed tomography scans were taken for each sample and then assessed by histological analysis. Results Higher amounts of osteoclastic activity and new collagen formation were observed in the deep penetration group when compared with the shallow penetration group. The former peaked at day 14 for both groups (1.53% ± 0.01% vs 0.03% ± 0.0004%, respectively), and the latter peaked at day 28 (0.65 × 106 ± 0.01 vs 0.08 × 106 ± 0.0008, respectively). Conclusions Within the limitations of this study, it appears that the intensity of the RAP in the rat is corticotomy depth dependent. This is to be kept in mind when decorticating the bone during surgically facilitated orthodontic procedures.

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