Brief Articles
Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jul 7, 2009; 15(25): 3166-3172
Published online Jul 7, 2009. doi: 10.3748/wjg.15.3166
Cardiopulmonary bypass induced microcirculatory injury of the small bowel in rats
Guo-Hua Dong, Chang-Tian Wang, Yun Li, Biao Xu, Jian-Jun Qian, Hai-Wei Wu, Hua Jing
Guo-Hua Dong, Chang-Tian Wang, Yun Li, Biao Xu, Jian-Jun Qian, Hai-Wei Wu, Hua Jing, Department of Cardiothoracic Surgery, Jinling Hospital, Clinical Medicine School of Nanjing University, Nanjing 210002, Jiangsu Province, China
Author contributions: Dong GH and Jing H designed the study; Wang CT and Wu HW performed the majority of experiments; Xu B contributed to data collection, analysis and interpretation; Qian JJ provided vital reagents and edited the manuscript; Li Y wrote the manuscript.
Correspondence to: Dr. Guo-Hua Dong, Department of Cardiothoracic Surgery, Jinling Hospital, Clinical Medicine School of Nanjing University, 305 Zhongshan East Road, Nanjing 210002, Jiangsu Province, China. dr.dongguohua@gmail.com
Telephone: +86-25-84819984   
Fax: +86-25-84819984
Received: December 16, 2008
Revised: May 29, 2009
Accepted: June 5, 2009
Published online: July 7, 2009
Abstract

AIM: To investigate microvascular injury quantitatively in the small bowel with respect to cardiopulmonary bypass (CPB) and related mechanisms.

METHODS: In 10 male SD rats, normothermic CPB was established and continued with a flow rate of 100-150 mL/kg per minute for 60 min, while another 10 sham-operated animals served as controls. An approximate 10-cm loop of the terminal ileum was exteriorized for observation by means of intravital fluorescence microscopy. The small bowel microcirculatory network including arterioles, capillaries, and collecting venules was observed prior to CPB, CPB 30 min, CPB 60 min, post-CPB 60 min and post-CPB 120 min. The intestinal capillary perfusion, microvascular permeability and leukocyte adherence were also measured.

RESULTS: The systemic hemodynamics remained stable throughout the experiment in both groups. In CPB animals, significant arteriolar vasoconstriction, blood velocity reduction and functional capillary density diminution were found. As concomitances, exaggerated albumin extravasation and increased leukocyte accumulation were also noted. These changes were more pronounced and there were no signs of restitution at the end of the observation period.

CONCLUSION: CPB induces significant microcirculatory injury of the small bowel in rats. The major underlying mechanisms are blood flow redistribution and generalized inflammatory response associated with CPB.

Keywords: Cardiopulmonary bypass, Functional capillary density, Intestinal microcirculation, Intravital microscopy