Collagen Content and Collagen Fiber Architecture in the Skin of Shamo Chicken, a Japanese Game Fowl

Collagen content and collagen fiber architecture in the skin of Shamo chickens were compared between sexes and body parts. Cervical, thoracic, dorsal, femoral, and crural skin samples were collected and their collagen content was analyzed. Collagen fiber specimens were prepared for scanning electron microscopy using the cell maceration method with a NaOH solution. Sex differences in collagen content were only observed in the femoral skin of mature chickens, but not in 10-week-old chicks. The difference in collagen content between body parts was obvious; femoral and crural skin had higher collagen content than those of other parts in both sexes. Scanning electron microscopy indicated that the collagen fiber architecture was quite different between the superficial and deep layers in the dermis, with the former consisting of loosely tangled band-like collagen fibers, and the latter composed of thick and dense layers of collagen bundles in a parallel arrangement. The width of collagen fibers in the superficial layer of the dermis differed between sexes in the dorsal, femoral, and crural skin. From these results, it is likely that the difference in collagen content in the femoral skin is not due to sex hormones but other factors, such as mechanical stimulation in daily activity. Additionally, collagen fiber width in the superficial layer is likely related to the difference in collagen content between sexes and between body parts

Glycerol induces early fibrosis in regenerating rat skeletal muscle

Glycerol has been recently used to induce muscle adiposity in mice. However, its effects on the rat muscles have not been investigated previously. Therefore, we investigated the regeneration outcomes of rat muscles following glycerol-induced injury at different time points. Glycerol injection induced myofiber degeneration with extensive inflammatory infiltration on day 4 followed by appearance of regenerating myotubes on day 7 after injury without adipocyte infiltration. Meanwhile, a significant collagen deposition at early stage of regeneration that increased together with persistent inflammatory infiltration up to day 14 after injury indicates impaired regeneration. In conclusion, glycerol injury in rats is more suitable as a fibrosis-inducing model than in mice due to earlier and higher accumulation of fibrous tissue with lacking adipogenesis.JSPS KAKENHI Grant Number 16H02585 and the Egyptian Government.https://www.jstage.jst.go.jpam2019Anatomy and Physiolog

Distribution of TNF receptors and TNF receptor-associiated intracellular signaling factors on equine tendinocytes in vitro

Although tumor necrosis factor (TNF)α is animportant key factor in degeneration of equine superficial digital flexor tendon (SDFT), the dynamism of TNF receptors and associated factors on tendinocytes has not been elucidated. To reveal signaling events mediated by TNF-receptors (TNF-Rs) in tendinocytes, we focused on four signaling factors, TNF-R1, TNF-R2, TNF-R-associated factor 2 (TRAF2) and nuclear factor-kappa B (NF-κB), and investigated the distribution and production of these factors. Cultured tendinocytes were obtained from SDFTs of thoroughbred horses. The tendinocytes were treated with 10ng/ml equine TNFα medium for 6 hours and then the four factors on tendinocytes were visualized by using an immunohistochemical method, and the amounts of the four factors were determined by Western blot analysis. Although TNF-R1 and TNF-R2 co-localized on the same tendinocyte, in untreated control cells (normal condition), immunoreactivity against TNF-R1 was very weak but TNF-R2 showed a strong reaction. However, TNF-R1 showed the same high level of reactionas TNF-R2 in TNFα-treated cells (inflamed condition). Intense TRAF2 and NF-κB were detected at inflamed condition, however both factors were also detected at normal condition. The distinct distributions of the four factors under diffrent conditions (normal and innamed condition) in vitro not only renect the dynamism of the cytokines but may also provide important clues for a means to prevent from occurrence of tendonitis and progress of tendon degeneration