Kim Jinu, Padanilam Babu J
1] Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA [2] Department of Anatomy, Jeju National University School of Medicine, Jeju, Republic of Korea.
1] Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA [2] Department of Internal Medicine, Section of Nephrology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
Kidney Int. 2015 Feb;87(2):350-8. doi: 10.1038/ki.2014.300. Epub 2014 Sep 10.
Signals that drive interstitial fibrogenesis after renal ischemia reperfusion injury remain undefined. Sympathetic activation manifests even in the early clinical stages of chronic kidney disease and is directly related to disease severity. A role for renal nerves in renal interstitial fibrogenesis in the setting of ischemia reperfusion injury has not been studied. In male 129S1/SvImJ mice, ischemia reperfusion injury induced tubulointerstitial fibrosis as indicated by collagen deposition and profibrotic protein expression 4 to 16 days after the injury. Leukocyte influx, proinflammatory protein expression, oxidative stress, apoptosis, and cell cycle arrest at G2/M phase were enhanced after ischemia reperfusion injury. Renal denervation at the time of injury or up to 1 day post injury improved histology, decreased proinflammatory/profibrotic responses and apoptosis, and prevented G2/M cell cycle arrest in the kidney. Treatment with afferent nerve-derived calcitonin gene-related peptide (CGRP) or efferent nerve-derived norepinephrine in denervated and ischemia reperfusion injury-induced kidneys mimicked innervation, restored inflammation and fibrosis, induced G2/M arrest, and enhanced TGF-β1 activation. Blocking norepinephrine or CGRP function using respective receptor blockers prevented these effects. Consistent with the in vivo study, treatment with either norepinephrine or CGRP induced G2/M cell cycle arrest in HK-2 proximal tubule cells, whereas antagonists against their respective receptors prevented G2/M arrest. Thus, renal nerve stimulation is a primary mechanism and renal nerve-derived factors drive epithelial cell cycle arrest and the inflammatory cascade causing interstitial fibrogenesis after ischemia reperfusion injury.
肾缺血再灌注损伤后驱动肾间质纤维化的信号仍不明确。交感神经激活甚至在慢性肾脏病的临床早期阶段就已出现,且与疾病严重程度直接相关。肾神经在缺血再灌注损伤背景下肾间质纤维化中的作用尚未得到研究。在雄性129S1/SvImJ小鼠中,缺血再灌注损伤在损伤后4至16天诱导了肾小管间质纤维化,表现为胶原沉积和促纤维化蛋白表达。缺血再灌注损伤后,白细胞浸润、促炎蛋白表达、氧化应激、细胞凋亡以及G2/M期细胞周期阻滞均增强。在损伤时或损伤后1天内进行肾去神经支配可改善组织学,降低促炎/促纤维化反应和细胞凋亡,并防止肾脏出现G2/M细胞周期阻滞。在去神经支配且缺血再灌注损伤诱导的肾脏中,用传入神经来源的降钙素基因相关肽(CGRP)或传出神经来源的去甲肾上腺素进行治疗可模拟神经支配,恢复炎症和纤维化,诱导G2/M阻滞,并增强TGF-β1激活。使用各自的受体阻滞剂阻断去甲肾上腺素或CGRP功能可防止这些效应。与体内研究一致,用去甲肾上腺素或CGRP处理可诱导HK-2近端小管细胞出现G2/M细胞周期阻滞,而针对其各自受体的拮抗剂可防止G2/M阻滞。因此,肾神经刺激是一种主要机制,肾神经衍生因子驱动上皮细胞周期阻滞和炎症级联反应,导致缺血再灌注损伤后的间质纤维化。