Effect of botulinum toxin type A and magnesium sulfate on random-pattern skin flap survival in rats
10.3760/cma.j.cn114453-20231023-00115
- VernacularTitle:A型肉毒毒素和硫酸镁对大鼠随意型皮瓣成活的影响
- Author:
Xi XU
1
;
Jinpeng HU
;
Wei ZHANG
;
Xinyi LI
;
Xiaojing LI
Author Information
1. 安徽医科大学第一附属医院整形外科，合肥 230022
- Keywords:
Surgical flaps;
Random-pattern skin flap;
Botulinum toxin type A;
Magnesium sulfate;
Vascular endothelial growth factor;
Rat
- From:
Chinese Journal of Plastic Surgery
2024;40(11):1157-1167
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the effects of botulinum toxin type A (BTX-A) and magnesium sulfate on the survival rate of random-pattern skin flaps (RSF) with different length-to-width ratios.Methods:Using a random number table method, 45 SD rats were divided into three groups: the saline group (Group A), the BTX-A group (Group B), and the magnesium sulfate group (Group C), with 15 rats in each group. Each group was further subdivided into three subgroups based on different length-to-width ratios of RSF (1∶1, 2∶1, 3∶1), with 5 rats in each subgroup. The preparation of the RSF involved using the midline of the rat’s back as the axis and the level 1 cm below the iliac crest line as the base, extending towards the head. The skin tissue was incised to the dorsal fascia layer, separating the subcutaneous tissue at the superficial layer of the deep fascia, while severing the blood vessels and their branches on both sides and at the base. After hemostasis, the flap was sutured in place. Immediately after surgery, 0.2 ml of saline, BTX-A (25 U/ml), or magnesium sulfate solution (50 mg/ml) was injected into the proximal, middle, and distal ends of the flap. On the seventh day post-surgery, the gross appearance of the flap was assessed, and the survival rate was calculated. The surviving flap tissue underwent hematoxylin and eosin (HE) staining to evaluate microvascular density (MVD) and the degree of vasodilation (including vessel outer diameter, inner diameter, and wall thickness). Immunohistochemistry was used to detect the expression level of vascular endothelial growth factor (VEGF). Statistical analysis was performed using GraphPad Prism 9.0.1 software, with data expressed as Mean ± SD. One-way ANOVA was used for multiple group comparisons, and Tukey’s test was used for pairwise comparisons.Results:On the seventh day post-surgery, flaps with a length-to-width ratio of 1∶1 healed well in all subgroups. In the case of flaps with a 2∶1 ratio, Group A exhibited partial necrosis at the distal end, characterized by blackened, non-elastic scabs and exudate. Groups B and C generally healed well. For flaps with a 3∶1 ratio, Group A exhibited extensive necrosis at both the middle and distal ends, with similar blackened, non-elastic scabs, non-bleeding cut sections, and exudate. Groups B and C showed only partial blackening at the distal end, with most areas healing effectively. The survival rates of flaps with a 1∶1 ratio did not show significant differences among the three groups ( P>0.05). Compared to Group A, Groups B and C had significantly higher survival rates for flaps with 2∶1 and 3∶1 ratios ( P<0.01), with no significant difference between Groups B and C ( P>0.05). HE staining indicated that as the length-to-width ratios increased, tissue edema and inflammatory cell infiltration also increased in all groups. Groups B and C had significantly reduced inflammatory changes compared to Group A, with a greater number of newly formed microvessels observed. Quantitative analysis revealed that MVD in Groups B and C was significantly higher than in Group A, regardless of the flap ratio ( P<0.05), with no significant difference between Groups B and C ( P>0.05). Vasodilation analysis showed that the outer diameter and wall thickness of vessels in Groups B and C were significantly greater than those in Group A ( P<0.05), with no significant difference between Groups B and C ( P>0.05). Immunohistochemical staining revealed that VEGF expression levels in Groups B and C were higher than in Group A, regardless of the flap ratio ( P<0.01). In flaps with a 1∶1 ratio, VEGF expression was higher in Group C than in Group B ( P<0.05), with no significant difference between the two groups for other flap ratios ( P>0.05). Conclusion:In RSF with length-to-width ratios of 2∶1 and 3∶1, subcutaneous injections of BTX-A or magnesium sulfate after replantation can promote the expansion and formation of blood vessels in the flap, increase the expression of VEGF, and improve the survival rate of the RSF.
