Mowlavi Arian, Reynolds Christopher, Neumeister Michael W, Wilhelmi Bradon J, Song Yao-Hua, Naffziger Ryan, Glatz Frank R, Russell Robert C
Southern Illinois University, Plastic Surgery Institute, Springfield, USA.
Ann Plast Surg. 2003 Apr;50(4):403-11. doi: 10.1097/01.SAP.0000041663.28703.54.
Free tissue transfers and replantation of amputated limbs are better tolerated by young adolescents than mature adults. The authors hypothesized that this observation may be, in part, because of an attenuated ischemia-reperfusion (IR) injury in younger patients. Because neutrophils have been identified as a critical cell line responsible for IR injury, the authors investigated the effects of animal age on the degree of neutrophil activation in a rat model. Activation was evaluated by monitoring expression of integrin surface markers (mean fluorescence intensity [MFI] of CD11b) and oxidative burst potential (MFI of dihydrorhodamine [DHR] oxidation) by flow cytometry in neutrophils analyzed after 4 hours of ischemia and 1, 4, and 16 hours of reperfusion in a gracilis muscle flap model in mature adult and young adolescent rats. Neutrophil activation was also evaluated in control sham-operated animals, which underwent elevation of gracilis muscle flaps without exposure to an ischemic insult. Muscle edema, determined by wet-to-dry muscle weight ratio, and muscle viability, determined by nitro blue tetrazolium (NBT) staining, were completed for gracilis muscles exposed to ischemia after 24 hours of reperfusion for each of the groups. Integrin expression, assessed by MFI of CD11b, was increased significantly in ischemic muscles of mature adult rats at 4 hours of reperfusion (71.10+/-3.53 MFI vs. 54.88+/-12.73 MFI, p=0.025). Neutrophil oxidative potential, assessed by MFI of DHR oxidation, was increased significantly in ischemic muscles of mature adult rats compared with young adolescent rats at 1 hour of reperfusion (78.10+/-9.53 MFI vs. 51.78+/-16.91 MFI, p=0.035) and 4 hours of reperfusion (83.69+/-15.29 MFI vs. 46.55+/-8.09 MFI, p=0.005). Increased edema formation was observed in the ischemic muscles of mature adult rats when compared with young adolescent rats (1.25+/-0.04 vs. 1.12+/-0.05, p=0.031) after 24 hours of reperfusion. A trend toward decreased muscle viability was observed in the mature adult rats when compared with young adolescent rats (23.7+/-3.1% NBT staining vs. 32.3+/-13.7% NBT staining, p=0.189) after 24 hours of reperfusion. The authors present evidence of an attenuated IR injury in young adolescent animals when compared with mature adult rats. These findings emphasize the importance that studies involving IR injury should be performed with consideration of animal age.
与成熟成年人相比,青少年对游离组织移植和断肢再植的耐受性更好。作者推测,这一观察结果可能部分归因于年轻患者的缺血再灌注(IR)损伤减轻。由于中性粒细胞已被确定为导致IR损伤的关键细胞系,作者在大鼠模型中研究了动物年龄对中性粒细胞激活程度的影响。通过在成熟成年大鼠和青少年大鼠的股薄肌皮瓣模型中,对缺血4小时以及再灌注1、4和16小时后的中性粒细胞进行流式细胞术检测,监测整合素表面标志物(CD11b的平均荧光强度[MFI])和氧化爆发潜能(二氢罗丹明[DHR]氧化的MFI)来评估激活情况。还对假手术对照组动物进行了中性粒细胞激活评估,这些动物进行了股薄肌皮瓣掀起但未遭受缺血损伤。对于每组再灌注24小时后暴露于缺血的股薄肌,通过湿重与干重之比测定肌肉水肿,并通过硝基蓝四氮唑(NBT)染色测定肌肉活力。通过CD11b的MFI评估的整合素表达,在成熟成年大鼠缺血肌肉再灌注4小时时显著增加(71.10±3.53 MFI对54.88±12.73 MFI,p = 0.025)。通过DHR氧化的MFI评估的中性粒细胞氧化潜能,在成熟成年大鼠缺血肌肉再灌注1小时(78.10±9.53 MFI对51.78±16.91 MFI,p = 0.035)和4小时(83.69±15.29 MFI对46.55±8.09 MFI,p = 0.005)时,与青少年大鼠相比显著增加。再灌注24小时后,与青少年大鼠相比,成熟成年大鼠缺血肌肉中观察到水肿形成增加(1.25±0.04对1.12±0.05,p = 0.031)。再灌注24小时后,与青少年大鼠相比,成熟成年大鼠中观察到肌肉活力有降低趋势(23.7±3.1% NBT染色对32.3±13.7% NBT染色,p = 0.189)。作者提供了证据表明,与成熟成年大鼠相比,青少年动物的IR损伤减轻。这些发现强调了在进行涉及IR损伤的研究时应考虑动物年龄的重要性。