Robertson Lynne M, Fletcher Nicole M, Diamond Michael P, Saed Ghassan M
Temple Therapeutics BV, Geleen, The Netherlands.
Department of Obstetrics and Gynecology, Wayne State University, 75 E Hancock St, Detroit, MI, 48201, USA.
Reprod Sci. 2019 Jun;26(6):724-733. doi: 10.1177/1933719118789511. Epub 2018 Sep 5.
Hypoxia and the resulting oxidative stress play a major role in postoperative tissue fibrosis. The objective of this study was to determine the effect of l-alanyl-l-glutamine (Ala-Gln) on key markers of postoperative tissue fibrosis: hypoxia-inducible factor (HIF) 1α and type I collagen.
Primary cultures of human normal peritoneal fibroblasts (NPF) established from normal peritoneal tissue were treated with increasing doses of Ala-Gln (0, 1, 2, or 10 mM) with hypoxia ([2% O] 0-48 hours; continuous hypoxia) or after hypoxia (0.5, 1, 2, 4 hours) and restoration of normoxia (episodic hypoxia) with immediate treatment with Ala-Gln. Hypoxia-inducible factor 1α and type 1 collagen levels were determined by enzyme-linked immunosorbent assay. Data were analyzed with 1-way analysis of variance followed by Tukey tests with Bonferroni correction.
Hypoxia-inducible factor 1α and type I collagen levels increased in untreated controls by 3- to 4-fold in response to continuous and episodic hypoxia in human NPF. Under continuous hypoxia, HIF-1α and type I collagen levels were suppressed by Ala-Gln in a dose-dependent manner. l-alanyl-l-glutamine treatment after episodic hypoxia also suppressed HIF-1α and type I collagen levels for up to 24 hours for all doses and up to 48 hours at the highest dose, regardless of exposure time to hypoxia.
l-alanyl-l-glutamine significantly suppressed hypoxia-induced levels of key tissue fibrosis (adhesion) phenotype markers under conditions of continuous as well as episodic hypoxia in vitro. This effect of glutamine on molecular events involved in the cellular response to insult or injury suggests potential therapeutic value for glutamine in the prevention of postoperative tissue fibrosis.
缺氧及由此产生的氧化应激在术后组织纤维化中起主要作用。本研究的目的是确定L-丙氨酰-L-谷氨酰胺（Ala-Gln）对术后组织纤维化关键标志物：缺氧诱导因子（HIF）1α和I型胶原蛋白的影响。
用递增剂量的Ala-Gln（0、1、2或10 mM）处理从正常腹膜组织建立的人正常腹膜成纤维细胞（NPF）原代培养物，分别处于缺氧状态（[2% O₂] 0 - 48小时；持续缺氧）或缺氧后（0.5、1、2、4小时）恢复常氧（间歇性缺氧）并立即用Ala-Gln处理。通过酶联免疫吸附测定法测定缺氧诱导因子1α和I型胶原蛋白水平。数据采用单因素方差分析，随后进行经Bonferroni校正后的Tukey检验进行分析。
在人NPF中，未处理的对照组中，缺氧诱导因子1α和I型胶原蛋白水平在持续和间歇性缺氧时增加3至4倍。在持续缺氧条件下，Ala-Gln以剂量依赖性方式抑制HIF-1α和I型胶原蛋白水平。间歇性缺氧后给予L-丙氨酰-L-谷氨酰胺处理，所有剂量下HIF-1α和I型胶原蛋白水平均被抑制长达24小时，最高剂量下长达48小时，且与缺氧暴露时间无关。
在体外持续和间歇性缺氧条件下，L-丙氨酰-L-谷氨酰胺显著抑制缺氧诱导的关键组织纤维化（粘连）表型标志物水平。谷氨酰胺对细胞对损伤或伤害反应中涉及的分子事件的这种作用表明谷氨酰胺在预防术后组织纤维化方面具有潜在的治疗价值。
