Cohen D, DeLeo V A
Columbia University, Department of Dermatology, New York, NY 10032.
Photochem Photobiol. 1993 Feb;57(2):383-90. doi: 10.1111/j.1751-1097.1993.tb02306.x.
Ultraviolet erythema in human skin is mediated in part by membrane derivatives of arachidonic acid (AA). UVA (320-400 nm) and UVB (290-320 nm) have been shown to induce release of AA from intact mammalian cells in culture. In order to investigate the mechanism of this release we examined the effect of UVA and UVB on release of [3H] AA from membrane preparations of murine fibroblasts. C3H 10T1/2 cells were prelabelled for 24 h with [3H] AA. The membrane fractions of the cells were separated after lysis by differential centrifugation. The membranes were irradiated in suspension and the [3H] AA released from the membranes was determined by scintillation spectroscopy of supernatants 3-4 h after irradiation. Both UVA and UVB induced release of AA from the membrane preparations. The response to UVB was small but significant, reaching levels approximately 150% of control release at doses of 1,200-4,000 J/m2. The response to UVA was larger; doses of 2.5-5.0 J/cm2 induced release equal to twice control (200%) levels, while doses of 10-20 J/cm2 induced maximal release at levels approximately 400% of control. Time course studies with UVB and UVA showed maximal release at 4 h after irradiation. When the membrane preparations were incubated with a polyclonal anti-phospholipase A2 antibody the UV induced release of [3H] AA was completely inhibited in both UVB (1200 J/m2) and UVA (10 J/cm2) treated cells.(ABSTRACT TRUNCATED AT 250 WORDS)
人类皮肤中的紫外线红斑部分是由花生四烯酸（AA）的膜衍生物介导的。已表明，紫外线A（320 - 400纳米）和紫外线B（290 - 320纳米）可诱导培养的完整哺乳动物细胞释放AA。为了研究这种释放的机制，我们检测了紫外线A和紫外线B对鼠成纤维细胞膜制剂中[3H] AA释放的影响。用[3H] AA对C3H 10T1/2细胞进行预标记24小时。细胞裂解后通过差速离心分离膜组分。将膜在悬浮液中照射，并通过照射后3 - 4小时上清液的闪烁光谱法测定从膜中释放的[3H] AA。紫外线A和紫外线B均诱导膜制剂释放AA。对紫外线B的反应较小但显著，在1200 - 4000 J/m2的剂量下达到对照释放水平的约150%。对紫外线A的反应较大；2.5 - 5.0 J/cm2的剂量诱导的释放等于对照的两倍（200%）水平，而10 - 20 J/cm2的剂量诱导的最大释放水平约为对照的400%。紫外线B和紫外线A的时间进程研究表明，照射后4小时释放最大。当膜制剂与多克隆抗磷脂酶A2抗体一起孵育时，在紫外线B（1200 J/m2）和紫外线A（10 J/cm2）处理的细胞中，紫外线诱导的[3H] AA释放均被完全抑制。（摘要截于250字）
