Title : Ozone and ultrasound in tattoo removal: Preliminary in vivo study
Abstract:
Tattoo removal, which is currently widely performed using the Nd:YAG laser, still has limitations such as pain and scar formation (Baleisis and Rudys, 2023; Chacur et al., 2014). Therapeutic ultrasound (TUS) has been used in the field of aesthetic health because it promotes biological effects such as increased skin permeability, as well as influencing cellular processes through cavitation and local heating (Alizadeh et al., 2016; Azagury et al., 2014; Ter Haar, 2007). Medical ozone (O?), in turn, has antimicrobial, anti-inflammatory and immunomodulatory properties, with lipoperoxidative action through mild oxidative stress (Liu et al., 2023; Sagai and Bocci, 2011). There are no studies evaluating the use of ozone and/or UST in the removal of pigments in biological tissues in vivo. In this study, 21 tattoo sites were analyzed (n = 7 tattoos × 3 pigs), distributed into four experimental groups: Control Group (C, n = 3), with no intervention; Ozone Group (O?, n = 6), treated with 1.0 mL of ozone gas and a concentration of 20 mg/L; Therapeutic Ultrasound Group (UST, n = 6), with application in continuous mode of 1 W/cm² for 5 minutes; and Hybrid Group (H, n = 6), which received both interventions according to the isolated protocols. After the tattoos had been applied, the patients waited 30 days for baseline healing before starting the experimental treatment, which consisted of 10 sessions, totaling 10 weeks. A skin biopsy was taken on the 11th week. The porcine animal model was chosen because of its similarity morphofunctional, physiological and immunological to humans (Lunney etal., 2021; Summerfield, Meurens and Ricklin, 2015). The tattoos were made with blue pigment, chosen because it is difficult to remove and easy to see. The macroscopic results showed that both ozone and therapeutic ultrasound (TUS), applied alone, promoted progressive lightening of the pigmented area over the course of the sessions. On the other hand, the hybrid protocol did not outperform the isolated approaches. Image analysis corroborated these findings, indicating greater depigmenting efficacy in the groups treated with ozone or UST independently. Histological evaluation confirmed the presence of moderate pigment in the control and hybrid groups, and slight pigment in those treated with ozone or UST alone. Ozone showed action through oxidative stress, while UST facilitated pigment dispersion by increasing permeability and cavitation. In the hybrid group, the thermal and oxidative interaction seems to have impaired the overall effectiveness of the treatment, and it is believed that the thermal and cavitational effect of UST may have negatively interfered with the cellular action of ozone through lipoperoxidation of the membranes. The findings indicate that ozone and UST promote partial depigmentation of recent blue tattoos in pigs, with histological and visual confirmation. Further investigations with old tattoos, different pigments, dosages and application intervals are needed to validate the efficacy of the technique (Schubert, Kluger and Schreiver, 2023; Snehota et al., 2020). The study concludes that both resources have the potential for safe and less invasive application in tattoo removal, especially with fewer side effects and patient discomfort.
