Luo Jian-Dong, Wang Ying-Ying, Fu Wei-Ling, Wu Jun, Chen Alex F
Department of Pharmacology, Michigan State University, East Lansing 48824-1317, USA.
Circulation. 2004 Oct 19;110(16):2484-93. doi: 10.1161/01.CIR.0000137969.87365.05. Epub 2004 Jul 19.
Nitric oxide (NO) deficiency contributes to diabetic wound healing impairment. The present study tested the hypothesis that increased cutaneous superoxide (O2-) levels in type 1 diabetic mice cause NO deficiency and delayed wound healing.
Wound healing was markedly delayed in streptozotocin-induced type 1 diabetic mice compared with the normal controls. There were significantly reduced levels of endothelial NO synthase (eNOS) protein and constitutive NOS activity in diabetic wounds, whereas O2- levels were markedly increased. A single regimen of cutaneous gene therapy of eNOS or manganese superoxide dismutase (MnSOD) restored such healing delay, with a concomitant suppression of wound O2- levels and augmentation of both eNOS protein and constitutive NOS activity. Gene therapy of MnSOD also increased cutaneous MnSOD activity. Cutaneous O2- levels were also increased in Ins2(Akita) diabetic mice. In vitro glucose treatment of cutaneous tissues from normal mice for 24 hours increased O2- levels in a concentration-dependent manner. The enhanced cutaneous O2- levels induced by high glucose in both normal and diabetic mice were abolished by the NADPH oxidase inhibitor apocynin and the protein kinase C inhibitor chelerythrine. Furthermore, ex vivo gene transfer of dominant-negative HA-tagged N17Rac1, which inhibits NADPH oxidase subunit Rac1, significantly inhibited cutaneous O2- formation induced by high glucose in both normal and Ins2(Akita) diabetic mice.
These results indicate that hyperglycemia augments cutaneous O2- levels, at least in part, via NADPH oxidase and protein kinase C pathways, resulting in impaired wound healing in type 1 diabetic mice. Gene therapy strategies aimed at restoring cutaneous NO bioavailability may provide an effective means to ameliorate delayed diabetic wound healing.
一氧化氮（NO）缺乏会导致糖尿病伤口愈合受损。本研究检验了以下假设：1型糖尿病小鼠皮肤中超氧化物（O2-）水平升高会导致NO缺乏和伤口愈合延迟。
与正常对照组相比，链脲佐菌素诱导的1型糖尿病小鼠的伤口愈合明显延迟。糖尿病伤口中内皮型一氧化氮合酶（eNOS）蛋白水平和组成型NOS活性显著降低，而O2-水平显著升高。单次进行eNOS或锰超氧化物歧化酶（MnSOD）的皮肤基因治疗可恢复这种愈合延迟，同时抑制伤口O2-水平，并增加eNOS蛋白和组成型NOS活性。MnSOD的基因治疗还增加了皮肤MnSOD活性。Ins2（Akita）糖尿病小鼠的皮肤O2-水平也升高。用正常小鼠的皮肤组织进行体外葡萄糖处理24小时，O2-水平以浓度依赖的方式增加。NADPH氧化酶抑制剂阿朴吗啡和蛋白激酶C抑制剂白屈菜红碱消除了正常和糖尿病小鼠中高糖诱导的皮肤O2-水平升高。此外，抑制NADPH氧化酶亚基Rac1的显性负性HA标记的N17Rac1的离体基因转移显著抑制了正常和Ins2（Akita）糖尿病小鼠中高糖诱导的皮肤O2-形成。
这些结果表明，高血糖至少部分通过NADPH氧化酶和蛋白激酶C途径增加皮肤O2-水平，导致1型糖尿病小鼠伤口愈合受损。旨在恢复皮肤NO生物利用度的基因治疗策略可能提供一种有效的手段来改善糖尿病伤口愈合延迟。
