Comparison of Antiaging Effects on Rat Skin of Cog Thread and Poly-L-Lactic Acid Thread

BACKGROUNDPolydioxanone Cog thread and poly-L-lactic acid (PLLA) thread have been used clinically for lifting and antiaging purposes. However, the histological changes in tissue and the efficacy of these 2 different types of thread have not been compared. OBJECTIVEThis study used hematoxylin and eosin (H&E) staining, Massonʼs trichrome staining, and electron microscopy (EM) to compare the results associated with the use of Cog thread and PLLA thread in rat skin. METHODSThirty female rats were divided into 3 groups of 10 rats eacha control group; a Cog group; and a PLLA group. Biopsy specimens obtained at 1, 3, and 6 months were examined using H&E, MT, and EM. RESULTSAlthough significant increases were observed in dermal thickness and the numbers of fibroblasts in the PLLA group compared with the control group within the first month (p.019), there were no significant differences between the Cog and control groups during this period (p.245). Dermal thickness (p.002) and numbers of fibroblasts (p.001) were similar in samples obtained from the PLLA and Cog groups at 3 and 6 months, and both groups showed significantly improved outcomes compared with the control group. CONCLUSIONPoly-L-lactic acid and Cog sutures were effective in facial rejuvenation; both increased dermis thickness and stimulated collagen production.