Efficacy of polynucleotide, fractional CO2 laser, and their combination in treating striae distensae: a randomized intraindividual clinical trial

Abstract

Striae distensae (SD), or stretch marks, are common atrophic dermal scars that can significantly impact psychological well-being. Despite various treatment options, effective management remains challenging. Fractional CO₂ laser (FrCO₂) therapy is widely used for its ability to stimulate collagen and elastin remodeling but carries a risk of post-inflammatory hyperpigmentation (PIH). Polynucleotides (PN), with larger molecular structures and higher concentrations than polydeoxyribonucleotide (PDRN), improve fibroblast viability and enhance collagen synthesis, both of which are essential for tissue repair and regeneration. This study aimed to evaluate the efficacy and safety of PN injections compared with FrCO₂ laser monotherapy and their combination in the treatment of SD. In a 20-week prospective, randomized, intraindividual clinical trial, twenty volunteers with SD persisting for over 12 months were enrolled. Each abdominal lesion was divided into three treatment zones: PN monotherapy, FrCO₂ laser monotherapy, and a combination of both. Outcomes were assessed using digital photography, Antera 3D imaging, and histological evaluations at baseline and weeks 4, 8, 12, and 20. Nineteen patients completed the trial which mean age was 42.45 ± 11.94 years. After a 20-week period, three treatment groups—polynucleotide injections, fractional CO2 laser, and their combination—showed significant improvement in the volume and width of striae (P < 0.001, mean vol change; -0.73, -0.67. -0.77, mean width change; -0.18, -0.18, -0.2 respectively). No statistically significant differences were found between groups regarding striae volume and width reduction; however, the combination therapy showed the highest mean reduction in improving both the volume and width of striae. Polynucleotide treatment was most effective in improving roughness and the Manchester scar scale of striae and exhibited fewer adverse effects compared to FrCO2 laser and combined therapy. Melanin levels increased in the laser and combined treatment groups but remained unchanged in the Polynucleotide group. In conclusion, PN injections are a safe and effective option for treating SD, with comparable efficacy to FrCO₂ laser and fewer side effects. The combination of PN and laser may offer enhanced outcomes through potential synergistic mechanisms however it still carries a high risk of PIH associated with FrCO₂. Further studies are needed to evaluate long-term efficacy and safety.