Effects of CyPA signal pathway in myocardial tissue after cardiopulmonary resuscitation in rats

Abstract

To investigate the changes in cyclophilin A (CyPA) signal pathway in rat myocardial tissue after cardiopulmonary resuscitation (CPR). Sixty-eight healthy male Sprague-Dawley (SD) rats were randomly divided into sham operation group (n = 8), instantaneous CPR after cardiac arrest (CA), immediate CPR after CA (CRP), and 15, 30, 60 and 120 minutes after CPR groups, respectively, with 10 rats in each group. Asphyxia was simulated by occlusion of the tracheal tube at the end of exhalation. Mechanical ventilation, compression and epinephrine injection were given for restoration of spontaneous circulation (ROSC) in order to reproduce cardiopulmonary resuscitation after cardiac arrest (CA-CPR) models in rats. Hemodynamic changes were recorded at different time points. The blood was collected from abdominal aorta, and myocardial tissue was also harvested. The serum CyPA and CD147 levels were determined by enzyme-linked immunosorbent assay (ELISA). The protein positive cells and mRNA expression of CyPA and CD147 in myocardial tissue of the rats were determined by immunohistochemical and real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR ). The protein expressions of matrix metalloproteinases (MMP-2, MMP-9) and myeloperoxidase (MPO) in rat myocardial tissue were determined by Western Blot. The neutrophil infiltration in rat myocardial tissue was assessed by hematoxylin and eosin (HE) staining. The heart rate of rat was lowered to 0 with arterial pressure lowered immediately after CA. Arterial pressure was elevated to normal range immediately after CPR. Heart rate was restored at about 30 minutes later, and the dose of epinephrine was 50-60 µg, and ROSC time was 1-4 minutes. Compared with those of the sham group, serum CyPA and CD147 levels were gradually increased along with elongation of ROCS time within 120 minutes, and peaked at 120 minutes, CyPA was increased from (786.11 ± 3.93) µL to (2001.80 ± 10.61) µg/L, and CD147 was increased from (2.94 ± 0.02) µg/L to (5.99 ± 0.023) µg/L (P < 0.05 or P < 0.01). CyPA and CD147 mRNA expressions (A value) in rat myocardial tissue were gradually increased, and peaked at 120 minutes. Relative expression of CyPA at 120 minutes was 2.42 ± 0.05 when it was 1 in the control, and relative expression of CD147 at 120 minutes was 1.88 ± 0.10 (both P < 0.01). The immunohistochemical results under light microscope showed that the brown positive cells were gradually increased, which indicated that the expressions of CyPA and CD147 were increased. Expressions of MMP-2, MMP-9 and MPO (gray value) in myocardial tissue were also gradually increased, peaking at 120 minutes, and MMP-2 was increased from 0.396 ± 0.021 to 0.879 ± 0.020, MMP-9 was increased from 0.372 ± 0.009 to 0.819 ± 0.012, and MPO was increased from 0.176 ± 0.005 to 0.829 ± 0.018 (P < 0.05 or P < 0.01). No obvious neutrophil infiltration in myocardial tissue was found with HE staining. Expressions of CyPA and CD147 were up-regulated in serum and myocardial tissue after CPR in rats, which may be the markers of inflammatory reaction.