Ahmed Aisha S, Li Jian, Abdul Alim M D, Ahmed Mahmood, Östenson Claes-Göran, Salo Paul T, Hewitt Carolyn, Hart David A, Ackermann Paul W
Karolinska Institutet, Department of Clinical Neuroscience, Stockholm, Sweden.
Karolinska Institutet, Department of Molecular Medicine and Surgery, Karolinska University Hospital, Solna, Stockholm, Sweden.
PLoS One. 2017 Jan 25;12(1):e0170748. doi: 10.1371/journal.pone.0170748. eCollection 2017.
Metabolic diseases such as diabetes mellitus type-II (DM-II) may increase the risk of suffering painful connective tissue disorders and tendon ruptures. The pathomechanisms, however, by which diabetes adversely affects connective tissue matrix metabolism and regeneration, still need better definition. Our aim was to study the effect of DM-II on expressional changes of neuro- and angiotrophic mediators and receptors in intact and healing Achilles tendon. The right Achilles tendon was transected in 5 male DM-II Goto-Kakizaki (GK) and 4 age-matched Wistar control rats. The left Achilles tendons were left intact. At week 2 post-injury, NGF, BDNF, TSP, and receptors TrkA, TrkB and Nk1 gene expression was studied by quantitative RT-PCR (qRT-PCR) and their protein distribution by immunohistochemistry in intact and injured tendons. The expression of tendon-related markers, Scleraxis (SCX) and Tenomodulin (TNMD), was evaluated by qRT-PCR in intact and injured tendons. Injured tendons of diabetic GK rats exhibited significantly down-regulated Ngf and Tsp1 mRNA and corresponding protein levels, and down-regulated Trka gene expression compared to injured Wistar controls. Intact tendons of DM-II GK rats displayed reduced mRNA levels for Ngf, Tsp1 and Trkb compared to corresponding intact non-diabetic tendons. Up-regulated Scx and Tnmd gene expression was observed in injured tendons of normal and diabetic GK rats compared to intact Wistar controls. However, these molecules were not up-regulated in injured DM-II GK rats compared to their corresponding controls. Our results suggest that DM-II has detrimental effects on neuro- and angiotrophic pathways, and such effects may reflect the compromised repair seen in diabetic Achilles tendon. Thus, novel approaches for regeneration of injured, including tendinopathic, and surgically repaired diabetic tendons may include therapeutic molecular modulation of neurotrophic pathways such as NGF and its receptors.
II型糖尿病（DM-II）等代谢性疾病可能会增加患疼痛性结缔组织疾病和肌腱断裂的风险。然而，糖尿病对结缔组织基质代谢和再生产生不利影响的发病机制仍需进一步明确。我们的目的是研究DM-II对完整和愈合过程中的跟腱中神经和血管营养介质及受体表达变化的影响。在5只雄性DM-II Goto-Kakizaki（GK）大鼠和4只年龄匹配的Wistar对照大鼠中切断右侧跟腱。左侧跟腱保持完整。在损伤后第2周，通过定量逆转录聚合酶链反应（qRT-PCR）研究完整和损伤肌腱中神经生长因子（NGF）、脑源性神经营养因子（BDNF）、血小板反应蛋白（TSP）以及受体酪氨酸激酶A（TrkA）、酪氨酸激酶B（TrkB）和神经激肽1（Nk1）基因的表达，并通过免疫组织化学研究它们的蛋白质分布。通过qRT-PCR评估完整和损伤肌腱中肌腱相关标志物硬骨素（SCX）和肌腱调节蛋白（TNMD）的表达。与受伤的Wistar对照相比，糖尿病GK大鼠受伤的肌腱中Ngf和Tsp1 mRNA及相应蛋白水平显著下调，并下调Trka基因表达。与相应完整的非糖尿病肌腱相比，DM-II GK大鼠的完整肌腱中Ngf、Tsp1和Trkb的mRNA水平降低。与完整的Wistar对照相比，正常和糖尿病GK大鼠受伤的肌腱中观察到Scx和Tnmd基因表达上调。然而，与相应对照相比受伤的DM-II GK大鼠中这些分子未上调。我们的结果表明，DM-II对神经和血管营养途径有有害影响，这种影响可能反映了糖尿病跟腱中受损的修复过程。因此，包括肌腱病性损伤和手术修复的糖尿病肌腱在内的损伤再生新方法可能包括对神经营养途径如NGF及其受体进行治疗性分子调节。
