title: XTT-colorimetric assay as a marker of viability in cryoprocessed cardiac valve.
abstract: This study sought to evaluate the use of tetrazolium salt XTT reduction as an indicator of valvular viability in a cryoprocessed porcine cardiac homograft model. The XTT tetrazolium assays was based on the metabolic reduction of Sodium 3'-[1-(phenylamino-carbonyl)-3,4-Tetrazolium]-bis(4-methoxy-6-nitro) benzene sulfonic acid hydrate. The relationship between XTT reduction and: (1) leaflet tissue with various weight (n = 24); (2) morphometric evaluation (n = 30); (3) cadaveric ischemic intervals (n = 30); (4) freeze-thawing (n = 30) has been studied. The measurement of XTT reduction were significantly correlated with the weight of cardiac leaflets, in the range of 30 to 180mg (y=0.015x-0.063; r=0.99). Compared to morphometry of valvular damage, the reduction of mitochondrial enzymatic activity in cardiac leaflets was correlated with matrix cells without irreversible damage (r=0.89, P<0.005). The depletion of XTT reduction occurred dependent of ischemic time intervals. In general, freeze-thawing reduced more than 20% activity of mitochondrial dehydrogenase. We concluded that XTT tetrazolium assay is highly sensitive to determine valvular injury. The study demonstrated its potential for testing of cryopreserved cardiac valve.
authors.affiliation: Homograft Laboratory, Veterans General Hospital-Taipei, Taiwan, R.O.C.
authors.forename: J H
authors.initials: JH
authors.lastname: Lu
authors.forename: Y T
authors.initials: YT
authors.lastname: Chiu
authors.forename: H W
authors.initials: HW
authors.lastname: Sung
authors.forename: B
authors.initials: B
authors.lastname: Hwang
authors.forename: C K
authors.initials: CK
authors.lastname: Chong
authors.forename: S P
authors.initials: SP
authors.lastname: Chen
authors.forename: S J
authors.initials: SJ
authors.lastname: Mao
authors.forename: P Z
authors.initials: PZ
authors.lastname: Yang
authors.forename: Y
authors.initials: Y
authors.lastname: Chang
mesh_terms: D000818:Animals; D015415:Biomarkers; D003124:Colorimetry / Q000379:methods*; D015925:Cryopreservation; D006351:Heart Valves / Q000473:pathology / Q000502:physiology*; D008854:Microscopy, Electron; D008928:Mitochondria / Q000201:enzymology; D017202:Myocardial Ischemia / Q000378:metabolism; D010088:Oxidoreductases / Q000032:analysis / Q000378:metabolism*; D013552:Swine; D013778:Tetrazolium Salts / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D013778:Tetrazolium Salts; C059087:2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide; D010088:Oxidoreductases