Bloomer Steven A
Division of Science and Engineering, Penn State Abington, Abington, Pennsylvania.
J Histochem Cytochem. 2025 Sep-Oct;73(9-10):329-337. doi: 10.1369/00221554251374725. Epub 2025 Sep 24.
Macrophages have multiple roles in the heart including immune surveillance and extracellular matrix remodeling. Aging increases both collagen deposition and macrophage number in the heart; however, rodent models used to study cardiac macrophages have age-related comorbidities such as atherosclerosis and hypertension. The Fischer 344 rat does not develop these conditions with aging; therefore, the purpose of this study was to evaluate macrophage number and polarization in the hearts of aged (24-month) and young (6-month) Fischer 344 rats. Paraffin-embedded hearts were assessed for collagen deposition and immunolabeled for CD68, CD163, CD206, and galectin-3. Compared with young rats, significantly greater collagen deposition was observed in the old rats. There were no significant differences in CD68 or CD163 cells between age groups, but both CD206 and galectin-3 cells were more numerous in the aged animals. Double-immunofluorescence studies demonstrated that galectin-3 colocalized with both CD68 and CD163, suggesting that galectin-3 is found in cardiac macrophages. Further colocalization studies demonstrated similar proportions of CD68/CD163, CD68/CD163, and CD68/CD163 cells between age groups, suggesting that aging does not affect macrophage polarization. As CD206 and galectin-3 cells promote fibrosis, these results warrant future studies that delineate the specific roles of these cells in the aged heart.
巨噬细胞在心脏中发挥多种作用，包括免疫监视和细胞外基质重塑。衰老会增加心脏中的胶原蛋白沉积和巨噬细胞数量；然而，用于研究心脏巨噬细胞的啮齿动物模型存在与年龄相关的合并症，如动脉粥样硬化和高血压。Fischer 344大鼠不会随着年龄增长而出现这些病症；因此，本研究的目的是评估老年（24个月）和年轻（6个月）Fischer 344大鼠心脏中的巨噬细胞数量和极化情况。对石蜡包埋的心脏进行胶原蛋白沉积评估，并对CD68、CD163、CD206和半乳凝素-3进行免疫标记。与年轻大鼠相比，老年大鼠的胶原蛋白沉积明显更多。不同年龄组之间的CD68或CD163细胞没有显著差异，但老年动物中的CD206和半乳凝素-3细胞数量更多。双重免疫荧光研究表明，半乳凝素-3与CD68和CD163共定位，这表明半乳凝素-3存在于心脏巨噬细胞中。进一步的共定位研究表明，不同年龄组之间CD68/CD163、CD68/CD163和CD68/CD163细胞的比例相似，这表明衰老不会影响巨噬细胞极化。由于CD206和半乳凝素-3细胞会促进纤维化，这些结果值得未来开展研究来阐明这些细胞在老年心脏中的具体作用。
