Ibial enthesis, thus we may possibly suggest that each entheses present a equivalent organization on the collagen fibers. In between uncalcified and calcified fibrocartilage could be observed the tidemark, the location where mineralization with apatite abruptly begins [35], in our study the adult rats presented a double tidemark which has been interpreted as a consequence of `start-stop’ phases of calcification [36], inside the elderly rats only a single wavy tidemark is observed, which suggests an advanced degree of mineralization. Our study was realized in typical entheses, when it really is compared with Milz and colleagues (2004) [37] which the authors evaluated histopathology from the entheses in middle aged cadavers (mean 47 years-old) and elderly cadavers (imply 84 years-old), both studies observed that fibrocartilage is a typical qualities of all entheses from subjects of a wide age range that need to not merely be equated with pathological adjust. However, Milz and colleagues (2004) [37] suggest mechanical overload may induce bony spur formation, in their study it was observed in the lateral epicondyle, whereas in our study was not observed within the region analyzed. Moreover, in contrast to from our study which was not observed inflammatory cells, the above authors mention the presence of this cells about modest venules, and explain the majority ofPLOS A single | DOI:ten.1371/journal.pone.0153568 April 14,ten /Ultrastructural Study of Bone-Tendon Junction with the Calcaneal TendonFig 5. Transmission electron microscopy of bone-tendon junction on the calcaneal tendon of elderly Wistar rats. (A) Collagen fibers of your tendon (arrows), calcified fibrocartilage (*). Bar: 0.5 m, x5,000. (B) Osteocyte nucleus (white asterisk), lacuna (black asterisk), cellular method (arrows), bone (B). Bar: 0.5 m, x5,000. (C) Nucleus of fibrocartilage cell (N), rough endoplasmic reticulum (arrow), territorial matrix (*), interterritorial matrix (**). Bar: 0.five m, x5,000. (D) Nucleus of fibrocartilage cell (N), nucleolus (tiny arrow), mitochondria (arrowheads), cytoplasmic processes (bigger arrow), territorial matrix (*), inter-territorial matrixPLOS 1 | DOI:10.1371/journal.pone.0153568 April 14,11 /Ultrastructural Study of Bone-Tendon Junction on the Calcaneal Tendon(**). Bar: 0.5 m, x5,000. (E) Bands of collagen fibers in the tendon tissue (*).Icariin Biological Activity Bar: 1 m, x3,000.Biochanin A Autophagy (F) Striations on the collagen fibrils on the tendon, overlap (arrow), gap (arrowhead).PMID:23671446 Bar: 0.2 m, x75,000. doi:10.1371/journal.pone.0153568.gchanges seen in elderly cadavers had been degenerative as opposed to inflammatory and suggests that such degenerative alterations are typical in elderly people. Our observations in the fibrocartilage cells demonstrates a morphology rounded/elongated housed inside the lacunae, revealing numerous cytoplasmic processes of diverse lengths. The cytoplasmic processes are detached within the territorial matrix, plus the lacunae are formed when the collagen fibrils surround these processes forming interconnected three-dimensional structures [38]. Similarly for the fibrocartilage cells, the osteocytes present inside the analyzed area are also lodged inside the lacunae formed by a complex network of collagen fibers. The osteocytes extend cell processes within the canaliculi and communicate with neighboring cells. They’ve a dendritic morphology, and their cell body are fusiform in lengthy bones or rounded in flat bones [39]. Generally, lacunae and canaliculi of the lacuna-canalicular network are surrounded by bone matrix [40]. Lacunae c.