The Influence of Different Irradiation Regimens on Inflammation and Vascularization in a Random-Pattern Flap Model

Abstract

Background: Irradiation plays an important role in the oncological treatment of various tumor entities. The aim of the study was to investigate the influence of different irradiation regimens on random-pattern flaps at the molecular and histopathological levels. Methods: Twenty-five rats underwent harvesting of bilateral random-pattern fasciocutaneous flaps. The right flaps received irradiation, while the left flaps served as non-irradiated intraindividual controls. Five rats served as a non-irradiated control group. Four different irradiation regimens with give rats each were tested: 20 Gy postoperatively, 3 × 12 Gy postoperatively, 20 Gy preoperatively, and 3 × 12 Gy preoperatively. Two weeks after surgery, HE staining and immunohistochemical staining for CD68 and ERG, as well as PCR analysis to detect Interleukin 6, HIF-1α, and VEGF, were performed. Results: A postoperative cumulative higher dose of irradiation appeared to result in an increase in necrosis, especially in the superficial layers of the flap compared to preoperative or single-stage irradiation. In addition, we observed increased expression of VEGF and HIF-1α in all irradiation groups. Conclusion: Even though no statistically significant differences were found between the different groups, there was a tendency for fractional postoperative irradiation with a higher total dose to have a more harmful effect compared to preoperative or single-dose irradiation.

Application of Stem Cells Shows Antiinflammatory Effect in an Irradiated Random Pattern Flap Model

“…2024, 14, x FOR PEER REVIEW 5 of 11 normally distributed. Calculating 2 -ΔΔCt revealed the relative expression to previously operated non-irradiated control group [21].…”

“…The surgery and the irradiation procedures have already been described [20,21]. In brief, an orthovoltage X-ray device was used to perform the irradiation with a current of 20 mA and a voltage of 150 kV.…”

“…Each flap was divided first longitudinally and divided into thirds. As previously described, the stainings were performed on the cranial lateral third (Table 2) and the PCR analyses on the cranial medial third [21]. For performing the staining, the flaps were embedded in such a manner that they could be evaluated in all layers from dorsal to basal [21].…”

“…As previously described, the stainings were performed on the cranial lateral third (Table 2) and the PCR analyses on the cranial medial third [21]. For performing the staining, the flaps were embedded in such a manner that they could be evaluated in all layers from dorsal to basal [21]. Hematoxylin and eosin (H&E) staining and immunohistochemical stainings with CD68 (ED1 clone, Bio-Rad, Feldkrichen, Germany) as the pan-macrophage marker and ERG (clone EP111, Epitomics, Inc., Burlingame, CA, USA) for vessels were performed.…”

“…In a previous study, the influence of different irradiation regimes on flap perfusion in a random pattern rat model have been studied. It has been shown that preoperative fractional irradiation with a lower individual dose but a higher total dose has a more negative impact on flap perfusion compared to higher single stage irradiation [ 20 , 21 ]. Based on these findings, this study investigates the influence of different cells on preoperatively irradiated random pattern flaps.…”