EFFECT OF HYPERTENSION ON ARTERIAL STRUCTURE AND WOUND REPAIR AT THE MICROVASCULAR ANASTOMOSIS SITE USING STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS (SHRSP)

Different processes of microvascular wound healing under hypertension in comparison to normotension have been suspected. To explore these di fferences at the site of anastomotic wound repair, we performed microv ascular anastomoses of the femoral arteries in 12-week-old, stroke-pro ne hypertensive rats (SHRSP) whose maximum blood pressure reached 238 mm Hg and in normotensive age-matched Wistar Kyoto (WKY) rats. Morphol ogic changes under hypertension were examined via light microscopy. Th e arrangement and number of endothelial cells were examined using the en face silver staining technique. The plasma activity levels of facto r XIII were also measured in each group. Transitional healing at the m icrovascular anastomosis site was evaluated via scanning electron micr oscopy. The extent of endothelial migration over the exposed media aro und the needle holes was determined using a computerized graphic analy sis system. Histologic cross sections demonstrated a thickened media, with altered shape and arrangement of the smooth muscle cell nuclei in SHRSP arteries compared with WKY arteries. En face silver staining sh owed small and spindle-shaped endothelial cells with an irregular cell arrangement and distribution in SHRSP arteries relative to WKY arteri es. Factor XIII was increased 36% over baseline in SHRSP rats postoper atively; this was significantly higher than the increase in WKY rats ( P < 0.05). Although both SHRSP and WKY arteries had similar wound heal ing responses to microvascular anastomosis, endothelial cell migration over the exposed media was significantly accelerated in the SHRSP rat s. (C) 1993 Wiley-Liss, Inc.