为什么在伤口涂布胰岛素能显著加速愈合？
最初人们认为胰岛素只是一种在血液中调节血糖浓度的激素，然而来自加利福尼亚大学的研究者新近发现，把胰岛素直接涂布在皮肤伤口上能显著加速愈合过程。
部分使用胰岛素治疗的老鼠皮肤伤口愈合速度加快，伤口表皮细胞生长迅速，皮肤深部的真皮层内血管重建良好。在随后的人类皮肤细胞培养试验中，Manuela Martins-Green 和同事们研究了胰岛素在分子水平对角质化细胞的影响，包括对创伤后表皮细胞再生作用的影响以及对构筑血流管道的微血管内皮细胞的影响。通过各种细胞分子技术，研究者发现胰岛素对培养的人角质化细胞有促进增殖和扩散的作用。在培养的人微血管内皮细胞中，胰岛素仅仅对伤口处细胞有促进作用。
胰岛素功能在于激活一类叫作激酶的细胞信号蛋白（特定的致敏反应细胞，如磷脂酰肌醇-3激酶, 蛋白激酶B等）以及一种DNA元素结合蛋白（胆固醇调节元件结合蛋白），这种蛋白质能调节胆固醇及类胆固醇的生成。
慢性或难以愈合的创伤使美国人的健康及医疗保健系统付出了极大的代价，就像糖尿病一样对上百万活动不便的病人产生了很大影响。因为糖尿病是由机体不良产物或胰岛素的使用而导致的疾病，或许这有助于解释糖尿病和创伤难以愈合之间的关系。
Martins-Green介绍说，“这项研究很重要，因为当我们知道胰岛素对哪些细胞起作用以及对哪些分子蛋白有影响，我们或许就可以使胰岛素的作用发挥得更好，或者能够找到更多有类胰岛素功能的蛋白分子，以便于治疗那些遭受着难以愈合创伤的病人。”
From managing sugar to managing healing
Why applying insulin to wounds significantly enhances healing
Insulin is a hormone known primarily for regulating sugar levels in the blood, yet researchers at the University of California, Riverside, recently found that applying insulin directly to skin wounds significantly enhanced the healing process.
Skin wounds in rats treated topically with insulin healed faster"surface cells in the epidermis covered the wound more quickly and cells in the dermis, the deeper part of the skin, were faster in rebuilding blood vessels.
In follow-up studies of human skin cells in culture, Manuela Martins-Green and colleagues explored the molecular impact of topical insulin on keratinocytes, the cells that regenerate the epidermis after wounding, and on microvascular endothelial cells, the cells that restore blood flow.
Using various cell and molecular techniques, the researchers discovered that insulin stimulates human keratinocytes in culture to proliferate and migrate. In cultured human microvascular endothelial cells, the insulin stimulates only migration into the wound tissue. The insulin works by switching on cellular signaling proteins called kinases (specifically Src, PI3K, and Akt) and a protein (SREBP) that binds elements in DNA that regulate the production of cholesterol and its relatives.
Chronic or nonhealing wounds take an immense toll on American health and on health care systems. It particularly affects millions of patients with impaired mobility, as well as those with diabetes. Because diabetes is a disease caused by impaired production or utilization of insulin, this work may help explain the connection between diabetes and poor healing.
Says Martins-Green, "This work is important because when we know which cells respond to insulin and which molecules are involved, we may be able to develop ways in which we can make insulin work even better or find ways in which more affordable molecules that mimic these functions of insulin can be developed to treat people who suffer from poor healing."
http://www.eurekalert.org/pub_releases/2006-12/asfc-fms120706.php
编辑：蓝色幻想
