Department of Forensic Pathology, China Medical University School of Forensic Medicine, Liaoning Province, PR China.
Collaborative Laboratory of Intelligentized Forensic Science (CLIFS), PR China.
Histol Histopathol. 2019 Jul;34(7):745-753. doi: 10.14670/HH-18-072. Epub 2018 Dec 5.
HIPK2 is an evolutionarily conserved serine/threonine kinase and is considered a co-regulator of an increasing number of transcription factors modulating a variety of cellular processes, including inflammation, proliferation and fibrosis. Skeletal muscle injuries repair is an overlapping event between inflammation and tissue repair. There are no reports about HIPK2 expression in skeletal muscles after trauma. A foundational study on distribution and time-dependent expression of HIPK2 was performed by immunohistochemical staining, Western blotting and quantitative real-time PCR, which is expected to obtain a preliminary insight into the functions of HIPK2 during the repair of contused skeletal muscle in mice. An animal model of skeletal muscle contusion was established in 50 C57B6/L male mice. Samples were taken at 1, 3, 5, 7, 9, 14, 17, 21 and 28 days after contusion, respectively (5 mice at each posttraumatic interval). 5 mice were employed as control. No HIPK2-positive staining was detected in uninjured skeletal muscle. Intensive immunoreactivties of HIPK2 were observed in polymorphonuclear cells, round-shaped mononuclear cells, regenerated multinucleated myotubes and spindle-shaped fibroblastic cells in the contused tissue. The HIPK2-positive cells were identified as neutrophils, macrophages and myofibroblasts by double immunofluorescent procedure. HIPK2 protein and mRNA expression were remarkably up-regulated after contusion by Western blotting and qPCR analysis. The results demonstrated that the expression of HIPK2 is distributed in certain cell types and is time-dependently expressed in skeletal muscle after contusion, which suggested that HIPK2 may participate in the whole process of skeletal muscle wound healing, including inflammatory response, muscle regeneration and fibrogenesis.
HIPK2 是一种进化上保守的丝氨酸/苏氨酸激酶，被认为是越来越多转录因子的共调节剂，这些转录因子调节着各种细胞过程，包括炎症、增殖和纤维化。骨骼肌损伤修复是炎症和组织修复重叠的事件。目前尚无创伤后骨骼肌中 HIPK2 表达的报道。通过免疫组织化学染色、Western blot 和定量实时 PCR 对 HIPK2 的分布和时间依赖性表达进行了基础研究，有望初步了解 HIPK2 在小鼠挫伤性骨骼肌修复过程中的功能。在 50 只 C57B6/L 雄性小鼠中建立了骨骼肌挫伤动物模型。分别在挫伤后 1、3、5、7、9、14、17、21 和 28 天（每个创伤后间隔 5 只小鼠）取样本。设 5 只小鼠为对照组。未受伤的骨骼肌未检测到 HIPK2 阳性染色。在挫伤组织中，多形核细胞、圆形单核细胞、再生多核肌管和梭形成纤维细胞中观察到强烈的 HIPK2 免疫反应性。通过双免疫荧光程序，将 HIPK2 阳性细胞鉴定为中性粒细胞、巨噬细胞和成肌纤维细胞。Western blot 和 qPCR 分析显示，HIPK2 蛋白和 mRNA 表达在挫伤后显著上调。结果表明，HIPK2 的表达分布在某些细胞类型中，并在挫伤后骨骼肌中呈现时间依赖性表达，提示 HIPK2 可能参与骨骼肌创伤愈合的全过程，包括炎症反应、肌肉再生和纤维化形成。
