scholarly journals Early (5-Day) Onset of Diabetes Mellitus Causes Degeneration of Photoreceptor Cells, Overexpression of Incretins, and Increased Cellular Bioenergetics in Rat Retina

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1981
Author(s):  
Jennifer O. Adeghate ◽  
Crystal D’Souza ◽  
Orsolya Kántor ◽  
Saeed Tariq ◽  
Abdul-Kader Souid ◽  
...  

The effects of early (5-day) onset of diabetes mellitus (DM) on retina ultrastructure and cellular bioenergetics were examined. The retinas of streptozotocin-induced diabetic rats were compared to those of non-diabetic rats using light and transmission electron microscopy. Tissue localization of glucagon-like-peptide-1 (GLP-1), exendin-4 (EXE-4), and catalase (CAT) in non-diabetic and diabetic rat retinas was conducted using immunohistochemistry, while the retinal and plasma concentration of GLP-1, EXE-4, and CAT were measured with ELISA. Lipid profiles and kidney and liver function markers were measured from the blood of non-diabetic and diabetic rats with an automated biochemical analyzer. Oxygen consumption was monitored using a phosphorescence analyzer, and the adenosine triphosphate (ATP) level was determined using the Enliten ATP assay kit. Blood glucose and cholesterol levels were significantly higher in diabetic rats compared to control. The number of degenerated photoreceptor cells was significantly higher in the diabetic rat retina. Tissue levels of EXE-4, GLP-1 and CAT were significantly (p = 0.002) higher in diabetic rat retina compared to non-diabetic controls. Retinal cellular respiration was 50% higher (p = 0.004) in diabetic (0.53 ± 0.16 µM O2 min−1 mg−1, n = 10) than in non-diabetic rats (0.35 ± 0.07 µM O2 min−1 mg−1, n = 11). Retinal cellular ATP was 76% higher (p = 0.077) in diabetic (205 ± 113 pmol mg−1, n = 10) than in non-diabetic rats (116 ± 99 pmol mg−1, n = 12). Thus, acute (5-day) or early onslaught of diabetes-induced hyperglycemia increased incretins and antioxidant levels and oxidative phosphorylation. All of these events could transiently preserve retinal function during the early phase of the progression of diabetes.

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 621
Author(s):  
Ernest Adeghate ◽  
Crystal M. D’Souza ◽  
Zulqarnain Saeed ◽  
Saeeda Al Jaberi ◽  
Saeed Tariq ◽  
...  

Nociceptin (NC) consists of 17 amino acids (aa) and takes part in the processing of learning and memory. The role of NC in the induction of endogenous antioxidants in still unclear. We examined the effect of NC on the expression of endogenous antioxidants in kidney, liver, cerebral cortex (CC), and hippocampus after the onset of diabetes mellitus, using enzyme-linked immunosorbent assay and immunohistochemistry. Exogenous NC (aa chain 1–17; 10 µg/kg body weight) was given intraperitoneally to normal and diabetic rats for 5 days. Our results showed that catalase (CAT) is present in the proximal (PCT) and distal (DCT) convoluted tubules of kidney, hepatocytes, and neurons of CC and hippocampus. The expression of CAT was significantly (p < 0.05) reduced in the kidney of normal and diabetic rats after treatment with NC. However, NC markedly (p < 0.001) increased the expression CAT in the liver and neurons of CC of diabetic rats. Superoxide dismutase (SOD) is widely distributed in the PCT and DCT of kidney, hepatocytes, and neurons of CC and hippocampus. NC significantly (p < 0.001) increased the expression of SOD in hepatocytes and neurons of CC and the hippocampus but not in the kidney. Glutathione reductase (GRED) was observed in kidney tubules, hepatocytes and neurons of the brain. NC markedly increased (p < 0.001) the expression of GRED in PCT and DCT cells of the kidney and hepatocytes of liver and neurons of CC. In conclusion, NC is a strong inducer of CAT, SOD, and GRED expression in the kidney, liver and brain of diabetic rats.


2017 ◽  
Vol 95 (11) ◽  
pp. 1343-1350
Author(s):  
Aleksandra Vranic ◽  
Stefan Simovic ◽  
Petar Ristic ◽  
Tamara Nikolic ◽  
Isidora Stojic ◽  
...  

Currently, cardiovascular diseases are the leading cause of global mortality, while diabetes mellitus remains an important cause of cardiovascular morbidity. A recent study showed that patients with diabetes mellitus treated with mineralocorticoid receptor antagonists have improved coronary microvascular function, leading to improved diastolic dysfunction. In this study, we evaluated the influence of acute administration of spironolactone on myocardial function in rats with streptozotocin-induced diabetes mellitus, with special emphasis on cardiodynamic parameters in diabetic rat hearts. The present study was carried out on 40 adult male Wistar albino rats (8 weeks old). Rats were randomly divided into 4 groups (10 animals per group): healthy rats treated with 0.1 μmol/L of spironolactone, diabetic rats treated with 0.1 μmol/L of spironolactone, healthy rats treated with 3 μmol/L of spironolactone, and diabetic rats treated with 3 μmol/L of spironolactone. Different, dose-dependent, acute responses of spironolactone treatment on isolated, working diabetic and healthy rat heart were observed in our study. In healthy rats, better systolic function was achieved with higher spironolactone dose, while in diabetic rats, similar effects of low and high spironolactone dose were observed.


Author(s):  
Abbas Bakhteyari ◽  
Yasaman Zarrin ◽  
Parvaneh Nikpour ◽  
Zeinab Sadat Hosseiny ◽  
Zeinab Sadat Hosseiny ◽  
...  

Background: Diabetes mellitus deeply changes the genes expression of integrin (Itg) subunits in several cells and tissues such as monocytes, arterial endothelium, kidney glomerular cells, retina. Furthermore, hyperglycemia could impress and reduce the rate of successful assisted as well as non-assisted pregnancy. Endometrium undergoes thorough changes in normal menstrual cycle and the question is: What happens in the endometrium under diabetic condition? Objective: The aim of the current study was to investigate the endometrial gene expression of α3, α4, αv, Itg β1 and β3 subunits in diabetic rat models at the time of embryo implantation. Materials and Methods: Twenty-eight rats were randomly divided into 4 groups: control group, diabetic group, pioglitazone-treated group, and metformin-treated group. Real-time PCR was performed to determine changes in the expression of Itg α3, α4, αv, β1, and β3 genes in rat’s endometrium. Results: The expression of all Itg subunits increased significantly in diabetic rats’ endometrium compared with control group. Treatment with pioglitazone significantly reduced the level of Itg subunits gene expression compared with diabetic rats. While metformin had a different effect on α3 and α4 and elevated these two subunits gene expression. Conclusion: Diabetes mellitus significantly increased the expression of studied Itg subunits, therefore untreated diabetes could be potentially assumed as one of the preliminary elements in embryo implantation failure.


2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
P. P. Wołkow ◽  
B. Bujak-Giżycka ◽  
J. Jawień ◽  
R. Olszanecki ◽  
J. Madej ◽  
...  

Purpose. Products of angiotensin (ANG) I metabolism may predispose to vascular complications of diabetes mellitus. Methods. Diabetes was induced with streptozotocin (75 mg/kg i.p.). Rat aorta fragments, isolated 4 weeks later, were pretreated with perindoprilat (3 μM), thiorphan (3 μM), or vehicle and incubated for 15 minutes with ANG I (1 μM). Products of ANG I metabolism through classical (ANG II, ANG III, and ANG IV) and alternative (ANG (1–9), ANG (1–7), and ANG (1–5)) pathways were measured in the buffer, using liquid chromatography-mass spectrometry. Results. Incubation with ANG I resulted in higher concentration of ANG II (P = 0.02, vehicle pretreatment) and lower of ANG (1–9) (P=0.048, perindoprilat pretreatment) in diabetes. Preference for the classical pathway is suggested by higher ANG III/ANG (1–7) ratios in vehicle (P=0.03), perindoprilat (P=0.02), and thiorphan pretreated (P=0.02) diabetic rat. Within the classical pathway, ratios of ANG IV/ANG II (P=0.01) and of ANG IV/ANG III (P=0.049), but not of ANG III/ANG II are lower in diabetes. Conclusions. Diabetes in rats led to preference toward deleterious (ANG II, ANG III) over protective (ANG IV, ANG (1–9), and ANG (1–7)) ANG I metabolites.


1999 ◽  
Vol 77 (12) ◽  
pp. 980-985 ◽  
Author(s):  
Jean-François Bouchard ◽  
Éric C Dumont ◽  
Daniel Lamontagne

Functional dilatory response in streptozotocin-induced diabetic rats was investigated using thoracic aortas, isolated hearts, and mesenteric beds. Dose-response curves to the PGI2 analogue iloprost on phenylephrine-preconstricted rings of diabetic rats and controls were comparable. In contrast, decreased vasodilation in diabetic rats was observed when dose-response curves to iloprost were performed in hearts and on phenylephrine-preconstricted mesenteric beds. Dose-response curves to forskolin, an adenylyl cyclase activator, performed with hearts and phenylephrine-preconstricted aortic rings and isolated mesenteric beds of diabetic rats and controls were comparable. However, a decreased vasodilation to the ATP-sensitive potassium channel (KATP) activator lemakalim was observed in diabetic hearts, but not in aortic rings and mesenteric beds. In conclusion, under our experimental conditions, diabetes mellitus affects the vasodilation to iloprost in both coronary and mesenteric beds, but not in the aorta. In the heart, this modification of vascular reactivity may be due to a decrease in KATP channel mediated response and not to a decreased activity of adenylyl cyclase. At this time, in the isolated mesenteric bed, the mechanism of this modification in vascular reactivity remains unknown.Key words: diabetes mellitus, iloprost, KATP channels, adenylyl cyclase, aorta, coronary circulation, mesenteric bed.


2013 ◽  
Vol 220 (3) ◽  
pp. 291-304 ◽  
Author(s):  
Mohamed Lotfy ◽  
Jaipaul Singh ◽  
Hameed Rashed ◽  
Saeed Tariq ◽  
Erika Zilahi ◽  
...  

Glucagon-like peptide 1 (GLP1) agonists are promising therapeutic agents in the treatment of diabetes mellitus. This study examines the mechanism of the protective effects of exenatide in experimental diabetes, employing four groups of ten rats each, in which two groups were streptozotocin-induced diabetic and two were control groups. One control and one diabetic group were treated with exenatide (1 μg/kg body weight (BW)) for 10 weeks. Blood plasma was taken for biochemical analyses while pancreatic tissue was taken for immunofluorescence and immunoelectron microscopy studies and real-time PCR to examine the expression of genes. The results show that exenatide improved BW gain and reduced blood glucose in diabetic rats compared with controls. Similarly, exenatide enhanced insulin release from the pancreatic fragments and improved liver and kidney functions and lipid profile in diabetic rats compared with controls. Exenatide not only induced significant increases in serum insulin level but also elevated the number of insulin-, GLP1- and exenatide-positive cells compared with untreated controls. Exenatide also elevated the number of catalase- and glutathione reductase-positive cells in diabetic rat pancreas compared with controls. Exenatide caused significant elevation in the expressions of pancreatic duodenal homeobox-1, heat shock protein-70, glutathione peroxidase, insulin receptor and GLP1 receptor genes in the pancreas of both control and diabetic rats compared with untreated animals. The results have demonstrated that exenatide can exert its beneficial and protective effects by elevating the levels of endogenous antioxidants and genes responsible for the survival, regeneration and proliferation of pancreatic β-cell.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Mengshan He ◽  
Pan Long ◽  
Lunfeng Guo ◽  
Mingke Zhang ◽  
Siwang Wang ◽  
...  

Aims. Diabetic retinopathy (DR) remains one of the leading causes of acquired blindness. Fushiming capsule (FSM), a compound traditional Chinese medicine, is clinically used for DR treatment in China. The present study was to investigate the effect of FSM on retinal alterations, inflammatory response, and oxidative stress triggered by diabetes. Main Methods. Diabetic rat model was induced by 6-week high-fat and high-sugar diet combined with 35 mg/kg streptozotocin (STZ). 30 days after successful establishment of diabetic rat model, full field electroretinography (ffERG) and optical coherence tomography (OCT) were performed to detect retinal pathological alterations. Then, FSM was administered to diabetic rats at different dosages for 42-day treatment and diabetic rats treated with Calcium dobesilate (CaD) capsule served as the positive group. Retinal function and structure were observed, and retinal vascular endothelial growth factor-α (VEGF-α), glial fibrillary acidic (GFAP), and vascular cell adhesion protein-1 (VCAM-1) expressions were measured both on mRNA and protein levels, and a series of blood metabolic indicators were also assessed. Key Findings. In DR rats, FSM (1.0 g/kg and 0.5 g/kg) treatment significantly restored retinal function (a higher amplitude of b-wave in dark-adaptation 3.0 and OPs2 wave) and prevented the decrease of retinal thickness including inner nuclear layer (INL), outer nuclear layer (ONL), and entire retina. Additionally, FSM dramatically decreased VEGF-α, GFAP, and VCAM-1 expressions in retinal tissues. Moreover, FSM notably improved serum antioxidative enzymes glutathione peroxidase, superoxide dismutase, and catalase activities, whereas it reduced serum advanced glycation end products, methane dicarboxylic aldehyde, nitric oxide, and total cholesterol and triglycerides levels. Significance. FSM could ameliorate diabetic rat retina damage possibly via inhibiting inflammation and improving antioxidation.


2015 ◽  
Vol 67 (2) ◽  
pp. 655-661 ◽  
Author(s):  
Tahir Ali ◽  
Farhat Shaheen ◽  
Madiha Mahmud ◽  
Hina Waheed ◽  
Muhammad Ishtiaq ◽  
...  

Patients with diabetes mellitus (DM) develop tendencies toward heart disease. Hyperglycemia induces the release of serotonin from enterochromaffin cells (EC). Serotonin was observed to elevate reactive oxygen species (ROS) and downregulate antioxidant enzymes. As a result, elevated levels of serotonin could contribute to diabetic complications, including cardiac hypertrophy. In the present study, diabetes mellitus was induced in rats by alloxan administration; this was followed by the administration of serotonin to experimental animals. ROS, catalase (CAT), superoxide dismutase (SOD), B-type natriuretic peptide (BNP) expression, and histopathological assessments were performed. Elevated ROS concentrations and decreased antioxidant enzyme activities were detected. Further, we observed an increase in cell surface area and elevated BNP expression which suggests that events associated with cardiac hypertrophy were increased in serotonin-administered diabetic rats. We conclude that serotonin secretion in diabetes could contribute to diabetic complications, including cardiac hypertrophy, through enhanced ROS production.


1984 ◽  
Vol 51 (03) ◽  
pp. 307-312 ◽  
Author(s):  
P D Winocour ◽  
M Laimins ◽  
J A Colwell

SummaryPlatelet survival in diabetes mellitus may be decreased or normal, and it is not clear whether altered platelet survival is due to a platelet or to a non-platelet defect. Therefore, platelet survival studies were performed at intervals up to 28 days in streptozotocin-induced diabetic and normal rats, using washed platelets from diabetic or normal animals.When compared to platelets from control rats, there was a significant decrease in platelet survival when platelets from 7 and 14 day diabetic rats were injected into normal controls or into diabetic rats.After 28 days of diabetes, platelet survival in diabetic rats was significantly lengthened, whether the platelets came from control or diabetic rats. Conclusions. (1) Shortened platelet survival in the diabetic rat is caused initially by a platelet defect. Later, non-platelet factors become dominant. (2) These findings may help explain reported discrepancies in results of platelet survival in diabetes mellitus.


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