West D C, Shaw D M, Lorenz P, Adzick N S, Longaker M T
Department of Immunology, University of Liverpool, U.K.
Int J Biochem Cell Biol. 1997 Jan;29(1):201-10. doi: 10.1016/s1357-2725(96)00133-1.
The lack of scarring and fibrosis in healing fetal skin wounds may relate to a prolonged presence of hyaluronan (HA). It has been suggested that fetal wounds may lack hyaluronidase, but the hyaluronidase levels in fetal wounds remain unknown. The size of HA influences its biological action, especially in relation to angiogenesis, which is also reduced in fetal wound healing. The present study determined the levels and size of HA, as well as hyaluronidase levels, in fetal and adult lamb wounds. Wire mesh cylinders, or polyvinyl acetate sponges, were placed subcutaneously in fetal lambs at 75, 100 or 120 days gestation. Wound fluid and wound tissue were harvested 3, 7 or 14 days later. Samples were digested with papain and both HA and hyaluronidase activity were determined in a competitive ELISA assay. Size distribution of HA was estimated using a Sephacryl S1000 column and fractions were collected for HA determination. Adult wound fluid HA remained low (4-5 micrograms/ml) over the 14 days. Fetal fluids were similar on day 3, but increased to 15-25 micrograms/ml by day 7. In 75/100-day wounds, HA remained elevated at 14 days, but in 120-day fluids decreased to levels similar to adult fluid. The HA in all fluids was polydisperse with a main peak at 200 kDa. Hyaluronidase levels were detected in all samples, reaching a peak 7 days post-wounding. In adult wound fluids hyaluronidase was much higher than the fetal wound fluids. These data suggest that lower hyaluronidase levels in fetal wounds may underlie the different pattern of HA deposition seen in fetal wounds.
胎儿皮肤伤口愈合过程中缺乏瘢痕形成和纤维化可能与透明质酸（HA）的长期存在有关。有人提出胎儿伤口可能缺乏透明质酸酶，但胎儿伤口中透明质酸酶的水平仍不清楚。HA的大小会影响其生物学作用，尤其是与血管生成相关的作用，而血管生成在胎儿伤口愈合中也会减少。本研究测定了胎儿和成年羔羊伤口中HA的水平和大小，以及透明质酸酶的水平。将金属丝网圆柱体或聚醋酸乙烯酯海绵皮下植入妊娠75、100或120天的胎儿羔羊体内。3、7或14天后收集伤口液和伤口组织。样品用木瓜蛋白酶消化，然后通过竞争性ELISA测定法测定HA和透明质酸酶活性。使用Sephacryl S1000柱估计HA的大小分布，并收集各部分用于HA测定。成年伤口液中的HA在14天内一直保持在较低水平（4-5微克/毫升）。胎儿伤口液在第3天情况类似，但到第7天增加到15-25微克/毫升。在75/100天的伤口中，HA在14天时仍保持升高，但在120天的伤口液中降至与成年伤口液相似的水平。所有伤口液中的HA都是多分散的，主峰在200 kDa。在所有样品中都检测到了透明质酸酶水平，在受伤后7天达到峰值。成年伤口液中的透明质酸酶比胎儿伤口液中的高得多。这些数据表明，胎儿伤口中较低的透明质酸酶水平可能是胎儿伤口中HA沉积模式不同的基础。
