The role of topical containing camellia sinensis in the cosmetic management of skin scars in healthy human volunteers: part 2

Epigallocatechin-3-gallate (EGCG), a polyphenol, influences cutaneous wound healing due to its anti-angiogenic, anti-inflammatory and anti-oxidant properties. We previously showed EGCG is effective in improving skin scarring when applied immediately post-injury. Here, this double-blinded randomized placebo-controlled trial compared the effects of pre-emptive priming versus immediate and delayed topical EGCG compared with placebo. This was evaluated in 40 healthy human volunteers, over 8 weeks, in scars created in their upper inner arms using skin punch biopsies. Participants were split into 4 groups; each undergoing different modes of application versus placebo: Group 1=priming (7D) pre-injury, Group 2=priming (3D) pre-injury, Group 3=immediate (0D) day-of-injury, Group 4=delayed application (14D) post-injury. RNA sequencing was used here based on 72 samples: Group 1: day 0 (n=3 placebo, n=3 EGCG), week 4 (n=3 placebo, n=3 EGCG), week 8 (n=3 placebo, n=3 EGCG); Group 2: day 0 (n=3 placebo, n=3 EGCG), week 4 (n=3 placebo, n=3 EGCG), week 8 (n=3 placebo, n=3 EGCG), Group 3: day 0 (n=6), week 4 (n=3 placebo, n=3 EGCG), week 8 (n=3 placebo, n=3 EGCG), Group 4: day 0 (n=6), week 4 (n=3 placebo, n=3 EGCG), week 8 (n=3 placebo, n=3 EGCG). The common differentially expressed genes identified between treated (EGCG) and placebo samples were grouped according to time point and group. Further exploration of these genes using Gene Ontology and Ingenuity Pathway Analysis revealed gene signatures of relevant biological processes and pathways. Here, RNA sequencing revealed a number of angiogenic, inflammatory genes that were significantly downregulated with EGCG particularly in pre-emptive priming Group 1 at week 4 including; hemoglobin subunit beta (HBB), hemoglobin subunit alpha-1 (HBA1) and hemoglobin subunit alpha-2 (HBA2) at week-4. Overall design: mRNA profiles of human skin scars over 8 weeks (treatment EGCG versus placebo) were generated by sequencing, in triplicate, using Illumina PE150 Platform.

表没食子儿茶素没食子酸酯（Epigallocatechin-3-gallate, EGCG）是一种多酚类物质，因其具备抗血管生成、抗炎及抗氧化特性，可对皮肤伤口愈合产生影响。既往研究表明，损伤即刻外用EGCG可有效改善皮肤瘢痕形成。本研究采用双盲随机安慰剂对照试验，比较损伤前预给药、即刻给药及延迟给药三种外用EGCG给药方式与安慰剂的效果差异。
本研究纳入40名健康人类受试者，在上臂内侧通过皮肤穿刺活检制造瘢痕模型，随访时长为8周。受试者被分为4组，分别采用不同给药方案联合安慰剂对照：第1组为损伤前7天预给药，第2组为损伤前3天预给药，第3组为损伤当日即刻给药，第4组为损伤后14天延迟给药。
本研究共纳入72份样本进行RNA测序（RNA sequencing）：第1组：第0天（安慰剂组n=3，EGCG组n=3）、第4周（安慰剂组n=3，EGCG组n=3）、第8周（安慰剂组n=3，EGCG组n=3）；第2组：第0天（安慰剂组n=3，EGCG组n=3）、第4周（安慰剂组n=3，EGCG组n=3）、第8周（安慰剂组n=3，EGCG组n=3）；第3组：第0天（n=6）、第4周（安慰剂组n=3，EGCG组n=3）、第8周（安慰剂组n=3，EGCG组n=3）；第4组：第0天（n=6）、第4周（安慰剂组n=3，EGCG组n=3）、第8周（安慰剂组n=3，EGCG组n=3）。
研究人员根据时间节点与分组，对给药组（EGCG）与安慰剂组样本间筛选得到的共同差异表达基因进行聚类分组。通过基因本体（Gene Ontology, GO）注释与Ingenuity通路分析（Ingenuity Pathway Analysis, IPA）对这些基因进行深入探究，揭示了相关生物学过程与通路的基因特征。RNA测序结果显示，EGCG可显著下调多个血管生成、炎症相关基因，尤其在第1组（损伤前预给药组）的第4周样本中，涉及的基因包括血红蛋白亚基β（hemoglobin subunit beta, HBB）、血红蛋白亚基α-1（hemoglobin subunit alpha-1, HBA1）及血红蛋白亚基α-2（hemoglobin subunit alpha-2, HBA2）。
总体实验设计：采用Illumina PE150测序平台，对8周随访周期内人类皮肤瘢痕组织的mRNA表达谱进行测序，每组设置3次生物学重复，涵盖EGCG给药组与安慰剂组的样本。