The aims of this study were to characterize and to compare the structural alterations of collagen and elastic fibers in the abdominal stretch marks of patients submitted to intralesional and per quadrant (region close to stretch marks) Platelet-Rich Plasma (PRP) treatment, as well as, to establish the possible mechanisms of action of this treatment involving toll-like receptors (TLRs) signaling pathways and growth factors. Incisional biopsies were collected from abdominal stretch marks with a 2 mm diameter punch in female patients, at the beginning of treatment, after 6 and 12 weeks of treatment, and submitted to morphological analyzes of elastic and collagen fibers, and immunohistochemistry for TLRs signaling pathways and growth factors. Our results demonstrated PRP per quadrant treatment was most effective in reducing the area of the abdominal stretch marks, with consequent stimulation of the synthesis and remodeling of collagen and elastic fibers. Also, PRP per quadrant treatment promoted an increase in TLR2 and TLR4 immunoreactivities, with consequent increase in TNF-α, VEGF and IGF-1. Based on the current findings, PRP constitutes a promising therapeutic approach in patients with stretch marks, since it promoted modulation of inflammatory cytokines and growth factors, with consequent remodeling of extracellular matrix, culminating with tissue improvement.

本研究的目的是表征并比较接受病灶内和每个象限（靠近妊娠纹的区域）富血小板血浆 (PRP) 治疗的患者腹部妊娠纹中胶原蛋白和弹性纤维的结构变化，以及因此，建立这种治疗涉及 Toll 样受体 (TLR) 信号通路和生长因子的可能作用机制。在治疗开始时、治疗6周和12周后，用直径2毫米的冲孔从女性患者的腹部妊娠纹中采集切口活检，并进行弹性纤维和胶原纤维的形态学分析，以及TLRs信号通路和免疫组织化学分析。生长因子。我们的结果表明，每象限 PRP 治疗对于减少腹部妊娠纹面积最为有效，从而刺激胶原蛋白和弹性纤维的合成和重塑。此外，每个象限的 PRP 治疗促进了 TLR2和 TLR4免疫反应性的增加，从而导致 TNF-α、VEGF 和 IGF-1 的增加。根据目前的研究结果，PRP 是妊娠纹患者一种有前途的治疗方法，因为它促进炎症细胞因子和生长因子的调节，从而重塑细胞外基质，最终改善组织。