National Yang-Ming University, Institute of Biophotonics, Taipei 112, Taiwan.
J Biomed Opt. 2013 Jun;18(6):061222. doi: 10.1117/1.JBO.18.6.061222.
Skin wounds heal when a series of cell lineages are triggered, followed by collagen deposition, to reconstruct damaged tissues. This study evaluates the regeneration of collagen and change in cellular metabolic rate in vivo during wound healing in rats, with second harmonic generation (SHG) and fluorescence lifetime imaging microscopy respectively. The metabolic rate of cells is reflected through the lifetime of the autofluorescence from the co-enzyme protein, reduced nicotinamide adenine dinucleotide, due to its change in the relative concentration of bound and free forms. A higher than normal cellular metabolic rate is observed during the first week of healing, which decreases gradually after eight days of wound formation. SHG signal intensity change indicates the net degradation of collagen during the inflammatory phase, and net regeneration begins on day five. Eventually, the quantity of collagen increases gradually to form a scar tissue as the final product. Importantly, this work demonstrates the feasibility of an in vivo imaging approach for a normal wound on rat skin, which has the potential to supplement the noninvasive clinical diagnosis of wounds.
当一系列细胞谱系被触发后，皮肤伤口会愈合，随后胶原蛋白沉积，以重建受损组织。本研究通过二次谐波产生（SHG）和荧光寿命成像显微镜分别评估了大鼠皮肤伤口愈合过程中胶原蛋白的再生和细胞代谢率的变化。由于结合态和游离态的相对浓度发生变化，辅酶蛋白还原型烟酰胺腺嘌呤二核苷酸（NADH）的自发荧光寿命反映了细胞的代谢率。在愈合的第一周观察到高于正常的细胞代谢率，在形成伤口后的第八天逐渐降低。SHG 信号强度变化表明在炎症期胶原蛋白的净降解，并且在第五天开始净再生。最终，随着最终产物瘢痕组织的形成，胶原蛋白的量逐渐增加。重要的是，这项工作证明了在正常大鼠皮肤伤口上进行体内成像方法的可行性，这有可能补充对伤口的非侵入性临床诊断。
