Effects of external gamma radiation on femoral artery reimplantation in rats: morphometrical analyzes

Abstract

Costa RFB, Fagundes DJ, Juliano Y, Novo NF, Vieira WTT. Effects of external gamma radiation on femoral artery reimplantation in rats: morphometrical analyzes. Acta Cir Bras [serial online] 2003 Mar-Apr;18(2). Available from URL: http://www.scielo.br/acb. ABSTRACT -Purpose: To investigate the effects of external gamma radiation on rat femoral artery reimplant. Methods: Sixty-two male Wistar rats were distributed in two groups I (Control) and II (Irradiated), both formed by three observation subgroups: 2 (10 animals), 7 (11) and 21(10) postoperative days (PO). The right femoral artery of each animal was split up and reimplanted (end-to-end anastomosis), through microsurgery technique. In the first PO day group II animals were irradiated with a single dose of 15Gy, external source. The histological analysis, qualitative and descriptive analysis, was accomplished through hematoxylin and eosin (HE), Verhoeff and Masson trichromium methodology. Morphometric analysis was realized in the same slides used to histological analysis stained by HE. Computer software was used to quantify morphological alterations of the vascular wall, by processing captured images from a microscope. It was analyzed the intimal layer (intimal hyperplasia and endothelium cells formation) and the nuclei percentage of smooth muscular cell in the medium layer and in the intima hyperplasia. The data were treated applying the statistical tests: Fisher s exact, Chi-square, Mann-Whitney, Kruskal-Wallis and analysis of variance (p < .05). Results: The patency graft was observed by microscope distal to the autograft in 93.5% (29/31). It was observed that the gamma-radiation reduced the degree of covering of the vascular wall for the neo-formed endothelium. The nuclei percentage of smooth muscular cells, in the media, was smaller compared to control animals, although it was no significant for the studied sample size. The irradiated group showed a significant lower luminal stenosis and the intimal hyperplasia occurrence. In this group the percentage of smooth muscular cells proliferation, in the media, were significantly lower for 7 and 21 days of observation. Conclusion: The external single dose of 15 Gy gamma-radiation delivered at first postoperative day may inhibit the endothelial cells regeneration and the percentage of lumen stenosis and prevents intimal hyperplasia, in the 2, 7 and 21 PO on femoral artery autograft in rats.

Inhibition of neointimal formation and hyperplasia in vein grafts by external stent/sheath

“…23,[42][43][44] Smaller trials with edifoligide (E2F) decoy oligodeoxynucleotide had shown favourable results in reducing the incidence of NIH. [45][46][47] However, when studied in large, multicenter, randomized trials it has failed to show reduction in the incidence of vein graft failure in patients undergoing CABG as well as lower extremity vein bypass. 48,49 These latter studies on E2F may support the role of remodelling as opposed to pure neointimal growth as the cause of vein graft failure.…”