Cardiac mitochondria alteration and peripheral vessel morphology in female diabetes

One of diabetes complications is chronic cardiomyopathty and fibrotic alteration of aorta and peripheral vessels. Diabetes has been correlated to ROS superproduction (Lashin et al., 2006) and an alteration of mitochondrial chain complexes function in the whole heart (Herelin et al., 2011). Despite diabetic cardiomyopathy is most frequent in women, to date studies on female experimental diabetic models are lacking. Our aim was to investigate on heart mitochondrial oxygen phosphorylation (OXPHOS), and on aorta and portal vein morphology in female Wistar rats, after 4 and half months of streptozotocin-induced (65 mg/kg) diabetes. Mitochondrial OXPHOS was assessed by means of a Clark-type electrode on the following isolated mitochondrial subpopulations: left and right ventricles subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria. Morphology and extracellular matrix composition of aorta and portal vein were investigated in light microscopy on paraformaldehyde fixed samples, stained with Masson Trichrome method (for collagen fibers) and Weigert’s stain (for elastic fibers). Evaluation of OXPHOS revealed an impairment of complex II in mitochondrial diabetic female rats in left and right IFM, but not in SSM. Interestingly, administration of the substrate glutamate resulted in an improvement of complex I efficiency in left IFM only, while association of complex I and II substrates displayed a reduced efficiency both in left and right IFM. Neither administration of glucidic substrates on SSM or of lipidic substrates on both SSM and IFM resulted in any change of mitochondrial OXPHOS efficiency. The study of connective fibrous composition in aorta and vena porta revealed a slight more abundant collagen production in the aorta’s wall and a disorganized and fragmented aspect of elastic bundles in the portal vein. Taken together, these data suggest a peculiar unknown development of diabetic cardiopathy in female rats

Subcellular distribution of melatonin receptors in rat parotid salivary glands: effect of melatonin intravenous infusion

The ultrastructural localization of melatonin receptors Mt1 and Mt2 in human salivary glands has previously been reported (Isola el al, 2013). In the acinar cells, the intragranular distribution of these receptors suggested to us that they may serve as a transcytotic system for melatonin. In an attempt to verify our working-hypothesis we currently exposed anaesthetized rats to the intravenous infusion of melatonin for 2 hrs. After another 30 min, the parotid gland on the right side was removed to be compared with prestimulation removed pieces of the left parotid gland serving as control specimens. Parotid gland tissues from 5 rats were cut into small pieces and fixed with a mixture of paraformaldehyde and glutaraldehyde. They were dehydrated, and embedded in Epon Resin. The ultrathin sections were collected on nickel grids and incubated overnight at 4ºC with an antibody specific for Mt1 and Mt2, respectively. The grids were then incubated for 1 hr with the appropriate secondary antibody conjugated to gold particles and, finally examined using electron transmission microscopy. In all sections, the immunoreactivity to Mt2 and, with less intensity, to Mt1 was principally expressed in secretory granules of acinar cells. Occasionally, plasma membranes were also stained, although slightly. Statistical analysis showed that, in response to melatonin, the immunogold particles reactive for Mt1, but not those for Mt2, increased. To conclude, in line with our hypothesis, melatonin stimulates an acinar carrier system, which seems predominantly to involve the Mt1 receptor, in order to delivery this hormone into saliva