Department of Systems Biology and Translational Medicine, College of Medicine, Texas A&M Health Science Center, Temple, 76504, USA.
Am J Physiol Heart Circ Physiol. 2012 Sep 15;303(6):H693-702. doi: 10.1152/ajpheart.00378.2012. Epub 2012 Jul 13.
We had previously proposed the presence of permanent stimulatory influences in the tissue microenvironment surrounding the aged mesenteric lymphatic vessels (MLV), which influence aged lymphatic function. In this study, we performed immunohistochemical labeling of proteins known to be present in mast cells (mast cell tryptase, c-kit, prostaglandin D(2) synthase, histidine decarboxylase, histamine, transmembrane protein 16A, and TNF-α) with double verification of mast cells in the same segment of rat mesentery containing MLV by labeling with Alexa Fluor 488-conjugated avidin followed by toluidine blue staining. Additionally, we evaluated the aging-associated changes in the number of mast cells located by MLV and in their functional status by inducing mast cell activation by various activators (substance P; anti-rat DNP Immunoglobulin E; peptidoglycan from Staphyloccus aureus and compound 48/80) in the presence of ruthenium red followed by subsequent staining by toluidine blue. We found that there was a 27% aging-associated increase in the total number of mast cells, with an ∼400% increase in the number of activated mast cells in aged mesenteric tissue in resting conditions with diminished ability of mast cells to be newly activated in the presence of inflammatory or chemical stimuli. We conclude that higher degree of preactivation of mast cells in aged mesenteric tissue is important for development of aging-associated impairment of function of mesenteric lymphatic vessels. The limited number of intact aged mast cells located close to the mesenteric lymphatic compartments to react to the presence of acute stimuli may be considered contributory to the aging-associated deteriorations in immune response.
我们之前提出，在衰老的肠系膜淋巴管（MLV）周围的组织微环境中存在永久性的刺激影响，这些影响会影响衰老的淋巴管功能。在这项研究中，我们对已知存在于肥大细胞中的蛋白质进行了免疫组织化学标记（肥大细胞胰蛋白酶、c-kit、前列腺素 D2 合酶、组氨酸脱羧酶、组胺、跨膜蛋白 16A 和 TNF-α），并通过用 Alexa Fluor 488 缀合的亲和素标记同一大鼠肠系膜段中的 MLV 来对肥大细胞进行双重验证，然后用甲苯胺蓝染色。此外，我们通过用各种激活剂（P 物质；抗大鼠 DNP 免疫球蛋白 E；金黄色葡萄球菌的肽聚糖和化合物 48/80）诱导肥大细胞激活，然后用甲苯胺蓝染色，评估了位于 MLV 处的肥大细胞数量的衰老相关变化及其功能状态。我们发现，在静止状态下，衰老的肠系膜组织中的肥大细胞总数增加了 27%，而激活的肥大细胞数量增加了约 400%，同时肥大细胞在存在炎症或化学刺激时新激活的能力降低。我们得出结论，衰老的肠系膜组织中肥大细胞更高程度的预先激活对于衰老相关的肠系膜淋巴管功能障碍的发展很重要。在靠近肠系膜淋巴管的部位，位于这些部位的数量有限的完整的衰老肥大细胞可能对急性刺激的存在做出反应，这可能是导致与衰老相关的免疫反应恶化的原因之一。
