Mitigated calcification of glutaraldehyde-fixed bovine pericardium by tannic acid in rats

• Published in: Chinese medical journal 2008-09, Vol.121 (17), p.1675-1679
• Main Authors: Wang, De, Jiang, Hong, Li, Jun, Zhou, Jian-Ye, Hu, Sheng-Shou
• Format: Article
• Language: English
• Subjects: Animals; Calcinosis - prevention & control; Cattle; Glutaral - pharmacology; Male; Matrix Metalloproteinase 9 - analysis; Pericardium - pathology; Rats; Rats, Sprague-Dawley; Tannins - pharmacology; Tenascin - analysis; Tissue Fixation; 丹宁酸; 围心膜; 巨噬细胞; 心瓣膜; 钙化作用
• ISSN: 0366-6999; 2542-5641
• DOI: 10.1097/00029330-200809010-00017

Background Bioprosthetic heart valves derived from glutaraldehyde （Glut）-fixed xenografts have been widely used to replace diseased cardiac valves. However, calcification and degeneration are common following their implantation. Inflammation is closely associated with calcification of Glut-fixed xenografts via macrophage infiltration. Tannic acid （TA） possesses anti-inflammatory effects. This study was designed to investigate the anti-calcification of TA treatment on the Glut-fixed bovine pericardium （BP） in a rat subdermal model. Methods Fresh BP was divided into two groups （10 in each group） and separately subjected to different fixation procedures as follows： （1） Glut group： fixation with 0.6% Glut alone; （2） Glut/TA group： fixation with 0.6% Glut and subsequent 0.3% TA. Then the BP samples were subdermally implanted in juvenile male Sprague-Dawley rats and explanted 21 days after implantation. Each explanted BP sample was divided into three parts for calcium content analysis von Kossa＇s staining and immunohistochemical staining, and reverse transcription-polymerase chain reaction study. Results The data from quantitative calcium analysis and von Kossa＇s staining showed that Glut-fixed BP developed significantly more calcification than Glut/TA-fixed BP （（90.3＋32.5） mg/g dry weight vs （6.4_＋1.3） mg/g dry tissue, P 〈0.01）. Immunostaining demonstrated lower matrix metalloproteinase-9 and tenascin-C expression as well as macrophage infiltration into Glut/TA-fixed BP than in its Glut-fixed counterpart （P 〈0.01 for all）. Additionally, the reverse transcription-polymerase chain reaction study showed that higher levels of expression of matrix metalloproteinase-9 and tenascin-C mRNA occurred within Glut-fixed BP than within the Glut/TA-fixed ones （P 〈0.01 for all）. Conclusion TA exerts excellent anti-calcification effects on Glut-fixed BP via inhibiting macrophage infiltration and expression of matrix metalloproteinase-9 and tenascin-C.