Pathogenesis of Focal Cytoplasmic Necrosis of the Smooth Muscle Cells in Hypertensive Rat Arterial Media

Hypertensive rat arteries exhibited severe medial smooth muscle cell injury and necrosis. Electron microscopic observations showed the smooth muscle cells of these arteries exhibited characteristics of focal cytoplasmic necrosis forming new cytodemarcating membrane between the healthy cytoplasm and necrotic cytoplasm. When the focal necrotic cytoplasm disappeared from the injured smooth muscle cells, it left it with a moth-eaten leaf-like appearance (moth-eaten necrosis). At an advanced stage of injury, smooth muscle cells changed to islet-like cell bodies with newly formed basement membranes around them, and further islet-like cell bodies and cell debris disappeared leaving lamellar and reticular basement membranes.In hypertensive rats injected with nitroblue tetrazolium (NBT), formazan deposits were observed in the medial cells and nitrotyrosine, a biomarker of peroxynitrite, were immunohistochemically observed in the arterial media. Nick-end positive extranuclear small granular bodies, which might have derived from focal necrotic cytoplasm and nucleus, were detected in the arterial media using DNA nick-end labeling method. Based on electron microscopical and histochemical findings, we conjectured that the focal cytoplasmic necrosis of the smooth muscle cells in the arterial media depended on injury arising from mitochondria-derived oxidants.     

Characterization of twenty-four polymorphic microsatellite loci of Rasbora borapetensis

Twenty-four microsatellite loci were isolated and characterized from the genome of Rasbora borapetensis. Flanking polymerase chain reaction primers were designed and used to amplify these loci in 32 individuals. All loci were polymorphic with allele numbers ranging from 2 to 27, observed heterozygosity from 0.031 to 1.000 and expected heterozygosity from 0.031 to 0.965. All loci conformed to the Hardy–Weinberg equilibrium and no evidence of null alleles was observed. Pairwise comparisons between alleles did not detect any linkage disequilibrium. The high level of polymorphisms observed in these microsatellite loci will enhance future investigations on the genetic differentiation and structure of populations of Rasbora borapetensis.