Diabetic cardiomyopathy is the leading cause of mortality in type 1 diabetes. Thus study of cardiomyocyte morphology and function during early stages of diabetes using modern analytical methods is of critical importance. Therefore, using confocal microscopy, we determined metric parameters, volumes and contractility, with calcium transients in isolated left-ventricular myocytes at one week after induction of diabetes in rats. Myocyte volume analysis from 3D confocal scans was performed using an automated contour detection algorithm that took the actual shape of the myocytes into account. We showed a significant reduction in myocyte volume in diabetic animals. We also showed a significant reduction in length and width but not in thickness of the myocytes, which suggests disproportional reorganization of the structure of the heart tissue during short-term diabetes. From a functional point of view, we observed a significant decrease in cell shortening at a stimulation frequency of 0.5 Hz. This was accompanied by a decrease in calcium transient amplitude. Together, these data suggest that impaired calcium handling is one of the factors that contributes to the observed decrease in myocyte shortening during early stages of streptozotocin-induced diabetes in rats.
- MeSH
- algoritmy MeSH
- časové faktory MeSH
- diabetická kardiomyopatie etiologie metabolismus patologie patofyziologie MeSH
- elektrická stimulace MeSH
- experimentální diabetes mellitus chemicky indukované komplikace MeSH
- interpretace obrazu počítačem MeSH
- kardiomyocyty metabolismus patologie MeSH
- konfokální mikroskopie MeSH
- kontrakce myokardu * MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- streptozocin MeSH
- tvar buňky * MeSH
- vápníková signalizace MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this study, we report for the first time concurrent measurements of membrane potential and dynamics and respiratory chain activities in rat heart mitochondria, as well as calcium transients in the hearts of rats in an early phase of streptozotocin diabetes, not yet accompanied with diabetes-induced complications. Quantitative relationships among these variables were assessed. The mitochondria from diabetic rats exhibited decreased fluorescence anisotropy values of diphenylhexatriene. This indicates that hydrophobic core of the membranes was more fluid compared with controls (p<0.05). We discuss the changes in fluidity as having been associated with augmented energy transduction through the diabetic membranes. Reduced ratio of JC-1 fluorescence (aggregates to monomers) in the mitochondria from diabetic hearts reflected descendent transmembrane potential. A significant negative association between membrane fluidity and potential in the diabetic group was found (p<0.05; r=0.67). Further, we observed an increase in calcium transient amplitude (CTA) in the diabetic cardiomyocytes (p=0.048). We conclude that some of the calcium-induced regulatory events that dictate fuel selection and capacity for ATP production in diabetic heart occur at the membrane level. Our findings offer new insight into acute diabetes-induced changes in cardiac mitochondria.
- MeSH
- experimentální diabetes mellitus metabolismus patofyziologie MeSH
- financování organizované MeSH
- fluidita membrány MeSH
- kardiomyocyty metabolismus MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- membránový potenciál mitochondrií MeSH
- mitochondriální membrány fyziologie MeSH
- myokard metabolismus MeSH
- oxidativní fosforylace MeSH
- potkani Wistar MeSH
- spotřeba kyslíku MeSH
- srdce patofyziologie MeSH
- srdeční komory cytologie MeSH
- srdeční mitochondrie fyziologie MeSH
- vápník fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- MeSH
- ekotoxikologie MeSH
- embryonální vývoj MeSH
- lidé MeSH
- olovo izolace a purifikace škodlivé účinky MeSH
- placenta * anatomie a histologie patologie MeSH
- placentace MeSH
- počítačové zpracování obrazu metody využití MeSH
- těhotenství MeSH
- vývoj plodu MeSH
- znečištění životního prostředí * analýza škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- přednášky MeSH
- Geografické názvy
- Slovenská republika MeSH
