Ben-Shahar Y, Abassi Z, Pollak Y, Bitterman A, Kreizman-Shefer H, Koppelman T, Fuhrer A E, Hayari L, Sukhotnik I
Department of Pediatric Surgery B, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, 6 Weizmann st, 6423906, Tel Aviv, Israel.
Department of Physiology, The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
Pediatr Surg Int. 2019 Dec;35(12):1413-1420. doi: 10.1007/s00383-019-04569-z. Epub 2019 Oct 1.
Notch signaling plays important roles in maintaining intestinal epithelial homeostasis. When Notch signaling is blocked, proliferation ceases and epithelial cells become secretory. The purpose of the present study was to evaluate the role of Notch signaling pathway following intestinal ischemia-reperfusion (IR) injury in a rat model.
Male Sprague-Dawley rats were randomly divided into four experimental groups: Sham-24 and Sham-48 rats underwent laparotomy and were killed 24 or 48 h later, respectively; IR-24 and IR-48 rats underwent occlusion of SMA and portal vein for 30 min followed by 24 or 48 h of reperfusion, respectively. Enterocyte proliferation and enterocyte apoptosis were determined at killing. Notch-related gene and protein expression were determined using Real Time PCR, Western blotting and immunohistochemistry 48 h followed IR.
IR-48 rats demonstrated significantly increased rates of cell proliferation and increased cell apoptosis in both jejunum and ileum compared to Sham rats. IR-48 rats exhibited a significant decrease in Notch-1 protein expression (Western blot) that was coincided with a significant decrease in the number of Notch-1 positive cells (immunohistochemistry) in jejunum (35% decrease, p < 0.05) and ileum (twofold decrease, p < 0.05) as well as Hes-1 positive cells in jejunum (28% decrease, p < 0.05) and ileum (31% decrease, p < 0.05) compared to Sham-48 rats.
Forty-eight hours following intestinal IR in rats, accelerated cell turnover was associated by inhibited Notch signaling pathway. Intestinal stem cells differentiation toward secretory progenitors rather than differentiation toward absorptive cells is important at this phase of intestinal recovery.
Notch信号通路在维持肠道上皮稳态中发挥重要作用。当Notch信号通路被阻断时，细胞增殖停止，上皮细胞转变为分泌细胞。本研究的目的是评估在大鼠模型中肠道缺血再灌注（IR）损伤后Notch信号通路的作用。
雄性Sprague-Dawley大鼠随机分为四个实验组：假手术-24组和假手术-48组大鼠接受剖腹手术，分别在24或48小时后处死；IR-24组和IR-48组大鼠分别接受肠系膜上动脉（SMA）和门静脉阻断30分钟，随后再灌注24或48小时。处死时测定肠上皮细胞增殖和凋亡情况。IR后48小时，采用实时定量PCR、蛋白质免疫印迹法和免疫组织化学法测定Notch相关基因和蛋白表达。
与假手术组大鼠相比，IR-48组大鼠空肠和回肠的细胞增殖率显著增加，细胞凋亡增加。IR-48组大鼠Notch-1蛋白表达（蛋白质免疫印迹法）显著降低，同时空肠（降低35%，p<0.05）和回肠（降低两倍，p<0.05）中Notch-1阳性细胞数量（免疫组织化学法）以及空肠（降低28%，p<0.05）和回肠（降低31%，p<0.05）中Hes-1阳性细胞数量与假手术-48组大鼠相比显著减少。
大鼠肠道IR后48小时，细胞更新加速与Notch信号通路受抑制有关。在此肠道恢复阶段，肠道干细胞向分泌祖细胞而非吸收细胞分化很重要。
