Comparative effects of various absorbable threads in a rat model

Background: Conventional procedures including botulinum toxin and filler injections have their limitations in improving deep wrinkles and decreasing tissue laxity, and possess the propensity for vascular accidents. Absorbable thread is a recently commercialized field, but there is little evidence on comparative superiority. Objectives: We observed the effects of polydiaxanone (PDO) threads with different number of strands in relation to collagen production and histopathology in a rat model. Materials and methods: Dorsal skin of rat was divided into five different compartments and four different PDO threads and monofilament poly-lactic acid (PLA) thread were inserted. Tissue samples were obtained at week 1, 2, and 12 after the procedure for histopathologic review and real-time PCR for quantification of collagen. Results: Multiple PDO filaments produced more collagen at 2 weeks. Single-stranded PLA thread insertion resulted in more Col1α1 levels than the double PDO thread and also showed the most Col1α3 production at week 2. The amount of collagen showed a sharp decline at week 12. Histologic evaluation showed retained threads surrounded by fibrous capsule-like structure at week 12. Conclusion: We were able to observe more collagen production in multiple stranded PDO threads compared to a single strand and that increasing number of threads leads to more collagen synthesis.