Serum cardiac troponin I concentrations in ewes diagnosed with parturient paresis: correlation with blood ionized calcium and conventional cardiac enzymes
Calcium is an essential mineral for cardiac muscle excitation-contraction coupling and relaxation, and hypocalcemia results of a decrease in the myocardial contractiliy force and an increase of cardiac cell permeability. Therefore; it is possible to occur myocardial damage in ewes with parturient paresis that is a metabolic disease caused by decreased blood ionized calcium (iCa) concentrations. The objectives of this study were to investigate the presence of myocardial damage in ewes diagnosed with parturient paresis by measuring serum cardiac troponin I (cTnI) concentrations and whether there was a correlation among cTnI, iCa and conventional enzymes such as the myocardial band of creatine kinase (CK-MB), creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Twelve ewes diagnosed with parturient paresis (iCa ˂ 1.0 mmol/L) and 10 healthy control ewes (iCa ≥ 1 mmol/L) were used in the study. In order to analyze blood iCa, beta-hydroxybutyrate (β-OHB) and serum cTnI, CK-MB, CK, AST and LDH, venous blood samples were collected from vena jugularis. Serum cTnI concentrations were significantly increased in the patient group (1.11 ± 0.62 ng/mL) when compared to the control group (0.02 ± 0.01 ng/mL). The serum concentrations of CK-MB, CK, AST and LDH in the patient group were higher than control group. cTnI was positively correlated with AST (r = 0.639; P = 0.001), LDH (r = 0.553; P = 0.008) and CK (r = 0.598; P = 0.003). In addition, significant negative correlation was detected between cTnI and iCa (r = -0.867; P = 0.000). The results showed that myocardial damage occured in ewes with parturient paresis.