Time-course of cardiac troponin I release from isolated perfused rat hearts during hypoxia/reoxygenation and ischemia/reperfusion.
The study was designed to determine the time-course of cardiac troponin I (cTn-I) release in isolated and Langendorff-perfused rat hearts during hypoxia and reoxygenation (H/Reox), and after various durations of total ischemia and subsequent reperfusion (I/R). For this purpose, in H/Reox, cTn-I was measured with the conventional Access immunoassay (ng/ml) and a new immunoassay which operates at pg/ml, and compared with creatine kinase (CK), lactate dehydrogenase (LD) and cardiac troponin T (cTn-T). In I/R, cTn-I was compared with CK and LD. The anti-Tn-I mAbs used in cTn-I assays cross-react with cTn-I of the rat. A clear difference between time-courses and concentration levels of cTn-I in I/R and H/Reox models was found. In I/R, maximum release of cTn-I, CK and LD similarly occurred within minutes following reperfusion; however cTn-I did not return to baseline values. cTn-I levels were not linked to the duration of ischemia. In I/R, we were only able to detect small cTn-I concentrations. In H/Reox experiments, cTn-I, CK and LD increased time-dependently. We found higher cTn-I maximal peak levels detected with the Access immunoassay than with the new assay (median, 0.346 ng/ml per min/g dry wt vs 132 pg/ml per min/g dry wt). cTn-T maximal concentrations were lower than maximal cTn-I levels (median, 0.117 ng/ml per min/g dry wt). Time-courses of cTn-I release were roughly similar with both assays in the H/Reox model (r = 0.90). These data indicate that the cTn-I time-course is related to experimental model (I/R or H/Reox), but also likely depends on the sensitivity of cTn-I assays in such experimental conditions.
Laboratory of Cardiovascular Physiology, University of Montpellier-Nîmes, Nîme, France.
J P
JP
Bertinchant
A
A
Polge
E
E
Robert
N
N
Sabbah
P
P
Fabbro-Peray
S
S
Poirey
M
M
Laprade
B
B
Pau
J M
JM
Juan
J P
JP
Bali
J E
JE
de la Coussaye
M
M
Dauzat
D000818:Animals; D003402:Creatine Kinase / Q000032:analysis / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D007118:Immunoassay / Q000379:methods; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D017202:Myocardial Ischemia / Q000378:metabolism*; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D019210:Troponin I / Q000032:analysis / Q000378:metabolism*; D020107:Troponin T / Q000032:analysis / Q000378:metabolism
D019210:Troponin I; D020107:Troponin T; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase