Influence of liquid nitrogen preservation time on the morphology and mechanical characteristics of acellular vessel matrix

Chi Yi-fan, Lin Ming-shan, Sun Long, Hou Wen-ming, Sun Zhong-dong, Niu Zhao-zhuo, Sun Yong, Sheng Wei

Department of Cardiovascular Surgery, Qingdao Municipal Hospital, Qingdao   266001, Shandong Province, China

Chi Yi-fan☆, Doctor, Chief physician, Professor, Tutor of master, Department of Cardiovascular Surgery, Qingdao Municipal Hospital, Qingdao   266001, Shandong Province, China
chiyf@hotmail.com

Correspondence to: Sun Long, Doctor, Department of Cardiovascular Surgery, Qingdao Municipal Hospital, Qingdao   266001, Shandong Province, China
sunlongboshi@ yahoo.com.cn

Supported by: a grant from Qingdao Municipal Science and Technology Bureau, No. 06-2-2-6-nsh*

Received: 2008-05-17
Accepted: 2008-06-30

Abstract
BACKGROUND: As a natural scaffold biomaterial, acellular tissue matrix deserves further experiences for its clinical application, and the effect of preservation condition has attracted more and more attention.
OBJECTIVE: To observe the influence of liquid nitrogen preservation time on the morphology and mechanical characteristics of acellular vessel matrix.
DESIGN, TIME AND SETTING: A randomized control observation was completed in the Laboratory of Cardiovascular Surgery, Qingdao Municipal Hospital (Qingdao, Shandong, China) between August 2007 and May 2008.
MATERIALS: Ten New Zealand rabbits weighing 550-600 g were used to prepare acellular vessel matrix.
METHODS: Trypsin, hypertonic solutions and chemical detergent were applied for a multistep process to carry out the preparation of acellular vessel matrix from rabbit thoracic aorta. According to the liquid nitrogen preservation time, the vascular specimens were divided into four groups randomly, namely fresh group, 1 month group, 2 months group and 3 months group. Fresh group was not subjected to liquid nitrogen preservation.
MAIN OUTCOME MEASURES: Specimens were detected by hematoxylin-eosin stain and observed by scanning electron microscope for the mechanics test, including Lagrange strain, Lagrange stress, extension ratio and ultimate stress.
RESULTS: Hematoxylin-eosin stain results showed that, collagen fiber and elastic fiber in the acellular vessel matrix of fresh group retained the previous morphology and mesh structure, the cells were almost removed. Under scanning electron microscope, the collagen fiber of both groups was intact without fragmentation, showing a mesh or porous structure. The porosity was also identical between the two groups, (100-150)×(10-20) μm. There were no obvious differences between liquid nitrogen groups and fresh group in the morphology and mechanical characteristics (P > 0.05).
CONCLUSION: There are no obvious influence in the morphology, histology and mechanical characteristics of acellular vessel matrix by the different liquid nitrogen preservation time.

Chi YF, Lin MS, Sun L, Hou WM, Sun ZD, Niu ZZ, Sun Y, Sheng W.Influence of liquid nitrogen preservation time on the morphology and mechanical characteristics of acellular vessel matrix.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(27):5235-5238 [www.zglckf.com/zglckf/ejournal/upfiles/08-27/27k-5235(ps).pdf]