Ascorbic acid and calcitriol reduce TNF-α to improve the viability of modified McFarlane random skin flaps in Wistar rats

Abstract

Link of Video Abstract: https://youtu.be/8UIEdUv8za8 Introduction: Distal flap necrosis is one of the most common complications in flap procedure. Ascorbic acid (vitamin C) is one of the most widespread antioxidants available, while calcitriol, a metabolite of vitamin D, has anti-inflammatory and antioxidant properties. The purpose of this study was to determine the effect of ascorbic acid and calcitriol on the viability of Modified McFarlane random skin flaps in Wistar rats and its mechanism through suppression of proinflammatory cytokine Tumor Necrosis Factor-α (TNF-α). Methods: An experimental study used 28 Wistar rats, by creating a caudally based 3 cm x 9 cm Modified McFarlane random skin flap and divided into four groups. The first group was injected with 200 mg/kg/day ascorbic acid, the second group with 2μg/kg/day calcitriol, and the third group with 200 mg/kg/day ascorbic acid combined with 2μg/kg/day calcitriol was injected two hours after flap elevation for seven days, respectively. The control group was not given any intraperitoneal injection. After seven days, the percentage of flap viability rate was measured and tissue sampling was performed to measure the amount of capillary density and TNF-α in all groups. Results: The higher percentage of viable flap area was found in all treatment groups, the highest in the ascorbic acid group 80.63% (p<0.001). The highest capillary density was found in ascorbic acid combined with the calcitriol group (27/visual field, p<0.001) compared to all groups. It was also found that the amount of TNF-α in the tissue was lowest in the group administered by ascorbic acid combined with calcitriol compared to all groups 57.38 ng/L and 0.62 nmol/mL respectively compared to all groups (p<0.001). The higher percentage of viable flap area was correlated with a lower amount of TNF-α (p<0.001), but not correlated with the amount of capillary density (p>0.05). Conclusion: Ascorbic acid in combination with calcitriol improves the viability of Modified McFarlane random skin flaps by lowering TNF-α levels.