All authors are affiliated with the Division of Dermatology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Dermatol Surg. 2021 May 1;47(5):e174-e178. doi: 10.1097/DSS.0000000000002943.
Ultraviolet (UV) exposure contributes to skin hyperpigmentation. Recently, botulinum neurotoxin type A (BoNT-A) showed a promising protective effect on UVB-induced hyperpigmentation in both in vitro and animal models.
The study aimed to investigate the preventive effect of BoNT-A against UVB-induced hyperpigmentation in human subjects.
A prospective, double-blinded, randomized controlled trial was performed in 15 healthy participants. Four separate square areas on the abdomen were randomly injected intradermally with different dilutions of BoNT-A (1:2.5, 1:5, 1:7.5) and normal saline (control). Two weeks after injection, hyperpigmented spots were induced by UVB irradiation at the experimental sites. The lightness index and hyperpigmentation scores from blinded physician and participants were evaluated.
Fifteen participants completed the study. One week after UVB irradiation, all BoNT-A-treated sites had a significantly lower degree of hyperpigmentation than the control site in lightness index and hyperpigmentation scores from blinded physician and participants (p < .05). However, no statistically significant difference was observed between different concentrations of BoNT-A. No side effects were observed throughout the study period.
Intradermal BoNT-A injection provided a protective effect from UVB-induced hyperpigmentation. It may be used for other hyperpigmentation disorders that are aggravated by UVB.
紫外线（UV）暴露会导致皮肤色素沉着。最近，肉毒毒素 A 型（BoNT-A）在体外和动物模型中均显示出对 UVB 诱导的色素沉着具有有前景的保护作用。
本研究旨在探讨 BoNT-A 对人体 UVB 诱导的色素沉着的预防作用。
对 15 名健康参与者进行了前瞻性、双盲、随机对照试验。将不同浓度的 BoNT-A（1:2.5、1:5、1:7.5）和生理盐水（对照）分别以皮内注射的方式随机注射到腹部的四个不同的正方形区域。注射两周后，在实验部位用 UVB 照射诱导色素沉着斑。由盲法医生和参与者评估亮度指数和色素沉着评分。
15 名参与者完成了研究。在 UVB 照射后 1 周，所有 BoNT-A 治疗部位的亮度指数和盲法医生及参与者评估的色素沉着评分均明显低于对照部位（p<0.05）。然而，不同浓度的 BoNT-A 之间没有观察到统计学上的显著差异。整个研究期间未观察到任何副作用。
皮内注射 BoNT-A 可提供对 UVB 诱导的色素沉着的保护作用。它可能用于其他因 UVB 加重的色素沉着障碍。
