Nitric oxide as a stimulator for the expression of TRPV-4 in collateral vessels during arteriogenesis

Arteriogenesis describes the process of induced collateral arterys growth by fluid shear stress out of a preexisting arteriolar network after occlusion of the major artery. The aim of our study was to find out the role of nitric oxide (NO) and the mechanosensitive TRPV4-channel in a rat hinlimb model in which the superficial femoral artery was ligated. This model is well known and has been described several times before. Methods: 20 male Sprague Dawley Rats (280–320g) were included in this study. We performed, in all animals, a unilateral ligation of the superficial femoral artery and a sham-procedure on the contralateral side. 10 rats were treated with a continous intravenous infusion of detaNONOate (4 or 8 mg/7 days) with a mini osmotic pump system (ALZET®, model 2001) via a catheter in the proximal stump of the internal jugular vein. The other 10 animals were treated in the same way, but instead of detaNONOate, we infused an isotonic NaCl solution for 7 days, We observed clinical deficits, such as acral necrosis and neurological dysfunction of the hindlimb and we used a laser-doppler system (PeriScan PIM III®) to visualize the perfusion of the skin of both hindpaws on day 0 and 7. In order to determine the number and diameter of the formed collateral vessels we performed a post-mortem intraarterial angiography of the aorta, iliacal- and leg-arteries with bariumsulfate as contrast medium. The TRPV4-protein expression was determined semiquantitavely using immunohistochemistry on slices of the quadriceps and adductor mussels.