The Effect of Botulinum Toxin A on Ischemia-Reperfusion Injury in a Rat Model

Abstract

Introduction: While studies using various materials to overcome ischemia-reperfusion (IR) injury are becoming increasingly common, studies on the effects of botulinum toxin A (BoTA) on IR injury in musculocutaneous flaps are still limited. The purpose of this study was to examine our hypotheses that BoTA provide protection of musculocutaneous flap from ischemia-reperfusion injury.

Method: Five days after pretreatment injection (BoTA versus normal saline), a right superior musculocutaneous flap (6 × 1.5 cm in size) was made. Ischemia was created by a tourniquet strictly wrapping the pedicle containing skin and muscle for 8 h. After ischemia, the tourniquet was cut, and the musculocutaneous flap was reperfused.

Results: The overall survival percentage of flap after 8 h of pedicle clamping followed by reperfusion was 87.32 ± 3.67% in the control group versus 95.64 ± 3.25% in the BoTA group (p < 0.001). The BoTA group had higher expression of CD34, HIF-1α, VEGF, and NF-kB comparing to control group in qRT-PCR analysis.

Conclusions: In this study, we found that local BoTA preconditioning yielded significant protection against IR injury in a rat musculocutaneous flap model.

Figure 1

A harvesting of right superior musculocutaneous flap. Flap (6 × 1.5 cm in size) was made after the inferior origin was detached at the caudal border. Any musculofascial defect in the abdominal wall was closed primarily using Vicryl 4-0 (a). To prevent revascularization of the overlying flap, a 6 × 1.5 cm of tailored sterile surgical glove was placed under the flap following applying a tourniquet that tightly wrapped the pedicle containing muscle and skin (b).

Figure 2

Representative gross findings created by a tourniquet strictly wrapping the pedicle containing skin and muscle. (a) Immediately after ischemia creation; (b) 8 hrs after ischemia creation.

Figure 3

Representative gross findings of the musculocutaneous flaps in representative animals of the BoTA (a) and control (b) group. The BoTA group showed nearly complete survival of the flap whereas control group revealed partial necrosis of the flap.

Figure 4

Effects of BoTA on the Gene Expression of Muscle Tissue. Relative mRNA expression of CD34, HIF1α, NF-kB, and VEGF by qRT-PCR of the rectus muscle considering each gene expression of proximal area in control group as 1. Gene expression of the rectus muscle was higher in the BoTA group than in the control group with statistical significance except CD34 expression in distal area. ^∗p < 0.05.

Figure 5

Effects of BoTA on the Gene Expression of Skin Tissue. Relative mRNA expression of CD34, HIF1α, NF-kB, and VEGF by qRT-PCR of the skin considering each gene expression of proximal area in control group as 1. Gene expression of the skin was higher in the BoTA group than in the control group with statistical significance except HIF1α expression in middle area. ^∗p < 0.05.