# Tissue perfusion and its influencing factors in epigastrial adipocutanous flaps affected by ischemia-reperfusion in rats

## TL;DR

This study examines how ischemia-reperfusion injury affects tissue perfusion and healing in rat adipocutaneous flaps used in reconstructive surgery.

## Contribution

The study provides new insights into microcirculatory and histomorphological changes in ischemic flaps over time.

## Key findings

- Ischemic flaps showed reduced microcirculation and impaired erythrocyte deformability compared to non-ischemic flaps.
- Ischemia caused long-term alterations in collagen fiber organization and decreased tensile strength in flaps.
- Mastocyte numbers decreased in ischemic flaps, indicating possible inflammatory changes.

## Abstract

In reconstructive surgery, complications of flaps include thrombosis and necrosis, partly originated from ischemia-reperfusion (I/R) injury. Therefore, investigations on the factors that influence tissue perfusion are essential. We wished to investigate microcirculation, micro-rheological factors, histomorphological, and biomechanical alterations of adipocutaneous flaps with/without I/R.

In anesthetized rats, groin flaps were prepared bilaterally. On the left side, the vascular pedicle was clamped for 2 hours before re-suturing the flaps. Skin temperature and microcirculation were monitored before/after surgery and on the first, third, seventh, and 14th postoperative days, besides blood samplings for testing hematological parameters, erythrocyte deformability and aggregation. At the end of experiment, skin samples were taken for histological and tensile strength examinations.

The hematological and micro-rheological parameters reflected the acute phase reactions, showing erythrocyte deformability impairment and enhanced aggregation. The microcirculatory values of the ischemic flaps were lower than the contralateral ones even two weeks after surgery. The ischemic-side flaps shrank to a greater extent. Histology revealed that mastocyte number decreased, and the quantity and organization of collagen fibers were altered in ischemic flaps.

The microcirculatory and micro-rheological alterations during the regeneration of the flaps were well observed. Flap ischemia modulated the tissue perfusion parameters, tensile strength, collagen content, and fiber organization.