Role of mechanical strain in incisional hernia fibroblast function.

描述(申请人提供)：描述：7%-11%的剖腹手术伤口会发生切口疝气，这是一个巨大的医疗负担，每年的费用为25亿美元。我们的实验室发现，当剖腹手术的伤口被机械破坏并形成切口性疝气时，会导致成纤维细胞伤口的愈合缺陷。肌肉和肌腱损伤的模型表明，像腹壁这样的承载组织依赖于机械应变来发出修复信号，据信是通过激活伤口修复成纤维细胞的机械转导途径发生的。这一建议建立在这样的前提下，即承重组织中的伤口愈合严重依赖于成纤维细胞感受到的机械应变。这一新概念挑战了“无张力”技术是最好的手术模式，并询问是否实际上需要一个负载力来发出腹壁伤口修复的信号。我们的目的是：1.测试体外机械应变是否能刺激从剖腹手术破裂性伤口和腹股沟分离的成纤维细胞的伤口愈合活性；2.证实在体外去除张力后，这些成纤维细胞失去了增殖和合成功能。使用已建立的大鼠腹股沟模型，我们将从未受伤的对照组培养成纤维细胞。机械完好，破裂和疝气的伤口。为了测试第一个目标，这些培养的成纤维细胞将受到循环和静态拉伸，并评估：微观形态证据的机械应变和肌动蛋白应激纤维表达；测量增殖细胞核抗原(增殖细胞核抗原)和合成成纤维细胞对机械应变的反应；整合素和o-平滑肌肌动蛋白(ASMA)作为成纤维细胞分化的分子标志物；以及在体外MAP激酶阻断支持激活这些修复细胞中的机械转导通路后对应变信号的阻断。第二个目标将通过在恒定应变下培养上述群体并测量移除该应变信号对相同结果的影响来进行测试。我们期待我们的发现将阐明机械张力在成纤维细胞增殖中的作用，并为预防和修复剖腹手术伤口疝气的策略提供启示。与公共卫生相关：在美国，每年大约有400,000例腹股沟切口形成，约占所有剖腹手术伤口的11%，在24-58%的腹股沟修补手术中复发。这是一个巨大的卫生保健负担，也是患者发病率的一个重要原因。尽管“无张力”疝修补术的出现降低了复发率，但我们假设腹壁成纤维细胞需要适当的负荷力来修复承载伤口，而“无张力”修补术可能绕过腹壁修补术的一个重要机制。

DESCRIPTION (provided by applicant): Description: Incisional hernias occur in 7-11% of laparotomy wounds, a substantial health care burden with an annual cost of $2.5 billion. Our laboratory found that a fibroblast wound .healing defect is induced when laparotomy wounds are mechanically disrupted and form incisional hernias. Models of muscle and tendon injury suggest that load-bearing tissues like the abdominal wall are dependent on mechanical strain to signal repair, believed to occur through mechano-transduction pathways that activate wound repair fibroblasts. This proposal is founded on the premise that wound healing in load-bearing tissues is critically dependent on the mechanical strain sensed by fibroblasts. This new concept challenges the surgical paradigm that "tension-free" techniques are best and asks whether a load-force is in fact required to signal abdominal wall wound repair. We aim 1. to test whether mechanical strain In vitro stimulates wound healing activity in fibroblasts isolated from disrupted surgical laparotomy wounds and hernias, and 2. to confirm that these fibroblasts lose proliferative and synthetic function when strain is removed in vitro. Using an established rat hernia model, we will culture fibroblasts from unwounded controls. Mechanically Intact, Disrupted and Hernia wounds. To test the first aim, these cultured fibroblasts will be subjected to cyclic and static stretch, and assessed for: microscopic morphological evidence of mechanical strain and actin stress fiber expression; measurement of the proliferative (PCNA) and synthetic fibroblast response to mechanical strain; integrin and o-smooth muscle actin (aSMA) as molecular markers for fibroblast differentiation; and blockade of fibroblast response to strain signals following MAP kinase blockade supporting activation of a mechanotransduction pathway in these repair cells in vitro. The second aim will be tested by culturing the above groups under constant strain and measuring the effect of removing this strain signal on the same outcomes. We anticipate our findings will clarify the role of mechanical strain in fibroblast proliferation, with implications for strategies for prevention and repair of laparotomy wound hernias. PUBLIC HEALTH RELEVANCE: The rate of incisional hernia formation in the U.S. approaches 400,000 yearly, occurring in approximately 11 % of all laparotomy wounds, with reoccurrences in 24-58% of hernia repairs. This is a substantial health care burden and a significant cause of patient morbidity. Although the advent of the "tension-free" approach to hernia repair, considered the standard, has reduced recurrence rates, we hypothesize that an appropriate load-force is required for abdominal wall fibroblasts to heal the load-bearing wound, and "tension-free" approaches may circumvent an important mechanism for abdominal wall repair.