Med Lasers.  2022 Dec;11(4):219-228. 10.25289/ML.22.039.

Treatment with a 1,064 nm low-fluence Q-switched Nd:YAG laser in multipulse mode can delay repigmentation in a zebrafish model of laser toning in Republic of Korea: a before and after study

• Jung J
• Kim H
• Park J
• Hwang JK

• KMID: 2537595
• DOI: http://doi.org/10.25289/ML.22.039

Abstract

Background and Objectives
A novel multipulse mode has been developed for the Q-switched 1,064 nm Nd:YAG laser (Q-NYL) which may help prevent rebound pigmentation after laser toning for melasma. The present study compared the depigmentation efficacy and latency of single pulse and multipulse modes over a range of fluences using the zebrafish model.
Materials and Methods
Ninety zebrafish were equally allocated to 9 groups to compare a Q-NYL single pulse mode (QS) using a 7 mm collimated handpiece with double- (PTP), triple- (Q3) and quadruple- (Q4) pulse modes over a range of fluences. Timing and degree of repigmentation were analyzed at the 14- and 49-day post-treatment assessments in each group using light microscopy-captured microphotography with image analysis and a Student’s t-test.
Results
There was an attrition rate of around 1 zebrafish per group per assessment, leaving a minimum of 3 animals per group for the final assessment. All zebrafish showed significant pigment removal at the 2-week assessment (p < 0.01 to < 0.0001). However, the best result among all groups with a significantly longer pigment-free latency period at the 7-week assessment was obtained in the Q4 4 × 0.3 J/cm² /micropulse group, delivering the equivalent in the skin of 1.2 J/cm² (p < 0.0001 at 2 weeks, p < 0.01 at 7 weeks).
Conclusion
The quadruple pulse mode of Q-NYL laser toning demonstrated effective, safe and long-term repigmentation-free efficacy in the zebrafish model, suggesting potential translation to controlled and doubleblind studies on melasma in human patients.

Keyword

Melasma; Laser toning; Melanosome; Zebrafish; Multipulse mode