Ploidy in mesenteric vessels of aged spontaneously hypertensive and Wistar-Kyoto rats.

Long-term regulation of blood pressure in a hypertensive rat may be mediated by elevated DNA content of smooth muscle cells of resistance vessels. This study explores DNA changes represented by an increased frequency of polyploid cells in multiple levels of the mesenteric arterial tree of spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) control rats. Two ages were examined: 45 and 78-80 weeks of age. SHR and WKY rats did not differ in frequency of polyploid cells at any mesenteric branch level at either age. Although hypertension per se seemed not to be a factor, both species showed increased numbers of polyploid cells with aging at certain branch levels of the mesenteric arterial tree. The data in the current study support the idea that hypertension and aging may result in similar and possibly additive changes in DNA in the vessel wall.