Macchi Veronica, Porzionato Andrea, Sarasin Gloria, Petrelli Lucia, Guidolin Diego, Rossato Marco, Fontanella Chiara Giulia, Natali Arturo, De Caro Raffaele
Institute of Human Anatomy, Department of Molecular Medicine, University of Padua, Padua, Italy.
Cells Tissues Organs. 2016;201(3):220-31. doi: 10.1159/000442876. Epub 2016 Jan 22.
The infrapatellar fat pad (IFP) can be regarded as a peculiar form of fibro-adipose tissue localized close to the synovial membrane and articular cartilage. The aims of the present study were to analyze the microscopic anatomy of the IFP through histological and ultrastructural methods, comparing it with that of the subcutaneous tissue of the abdomen and of the knee. Ten specimens of IFP were sampled from bodies of the Donation Program of the University of Padua without a history of osteoarthritis. The IFP consisted of white adipose tissue, of lobular type, with lobules delimited by thin connective septa. The IFP lobule areas were smaller (p < 0.05) and the interlobular septa were thicker (p > 0.05) than those of subcutaneous tissues of the abdomen, whereas the IFP lobule areas were larger (p < 0.05) and the interlobular septa were thinner than those of the subcutaneous tissue of the knee (p < 0.05). The IFP adipocytes present a mean area of 3,708 ± 976 µm2 with a large intercellular space, whereas the mean area of the abdominal tissues was greater (6,082 ± 628 µm2; p < 0.05). At scanning electron microscopy the IFP adipocytes were covered by thick fibrillary sheaths, creating a basket around the adipocytes. The structural characteristics of the IFP (lobular aspect of the adipose tissue, thickness of the septa with scarce elastic fibers) could act as a plastic portion aimed at the absorption of pressure variation during knee articular activity. The extensive distribution of nerves suggests a possible role of the IFP as a mechanoreceptor, corresponding to a tridimensional connective mesh working in the proprioceptive regulation of the activity of the knee joint.
髌下脂肪垫（IFP）可被视为一种特殊形式的纤维脂肪组织，位于滑膜和关节软骨附近。本研究的目的是通过组织学和超微结构方法分析IFP的微观解剖结构，并将其与腹部和膝部的皮下组织进行比较。从帕多瓦大学捐赠项目的尸体中采集了10个无骨关节炎病史的IFP标本。IFP由小叶型白色脂肪组织组成，小叶由薄的结缔组织间隔分隔。与腹部皮下组织相比，IFP小叶面积较小（p<0.05），小叶间隔较厚（p>0.05）；而与膝部皮下组织相比，IFP小叶面积较大（p<0.05），小叶间隔较薄（p<0.05）。IFP脂肪细胞的平均面积为3708±976µm²，细胞间隙较大，而腹部组织的平均面积更大（6082±628µm²；p<0.05）。在扫描电子显微镜下，IFP脂肪细胞被厚厚的纤维鞘覆盖，形成围绕脂肪细胞的篮状结构。IFP的结构特征（脂肪组织的小叶形态、弹性纤维稀少的间隔厚度）可作为一个可塑性部分，旨在吸收膝关节活动期间的压力变化。神经的广泛分布表明IFP可能作为一种机械感受器，对应于一个在膝关节活动的本体感觉调节中起作用的三维结缔组织网。
