Supplementary Material for: Is Human Sebum the Source of Skin Follicular Ultraviolet-Induced Red Fluorescence? A Cellular to Histological Study

Background: The ultraviolet-induced red fluorescence (UVRF) from human skin follicles was suggested to be a result of Propionibacterium acnes and was used for the monitoring of acne. More recent studies suggested that the UVRF may be more related to sebum rather than to microorganisms. Objective: To clarify whether human sebum or follicular microorganisms are the source of UVRF. Methods: We examined the fluorescence of human-derived SZ95 sebocytes, human sebaceous glands, sebum extracted from the sebaceous glands, and bacteria isolated from human hair follicles under ultraviolet light. Results: SZ95 sebocytes, human sebaceous glands, and sebum do not emit UVRF. Two types of UVRF peaking at about 635 nm and at about 620 nm were detected in P. acnes and Staphylococcus epidermidis, respectively. This is the first report that S. epidermidis emits UVRF when it is anaerobically cultured and then exposed to air. Conclusion: Human follicular UVRF is emitted by resident bacteria, not by sebum. Therefore, UVRF may be used to monitor certain species of skin microorganisms.

背景：人体皮肤毛囊产生的紫外线诱导红色荧光（ultraviolet-induced red fluorescence, UVRF）曾被认为是痤疮丙酸杆菌（Propionibacterium acnes）作用的结果，并被应用于痤疮的监测。近期研究则提出，UVRF或更多与皮脂（sebum）相关，而非皮肤微生物。
研究目的：明确人体毛囊UVRF的来源为人体皮脂还是毛囊寄居的微生物。
实验方法：我们在紫外光照射条件下，检测了人源SZ95皮脂腺细胞（SZ95 sebocytes）、人体皮脂腺（sebaceous glands）、从皮脂腺中提取的皮脂，以及从人体毛囊中分离得到的细菌的荧光表现。
实验结果：SZ95皮脂腺细胞、人体皮脂腺及皮脂均未释放UVRF。痤疮丙酸杆菌（Propionibacterium acnes，下称P. acnes）与表皮葡萄球菌（Staphylococcus epidermidis）分别在约635 nm和约620 nm处出现UVRF特征峰。本研究首次报道，表皮葡萄球菌经厌氧培养并暴露于空气后可产生UVRF。
研究结论：人体毛囊的UVRF由寄居的皮肤细菌产生，而非皮脂。因此，UVRF可用于监测特定种类的皮肤微生物。