2.4. Hemodynamic and Electrophysiological Analysis
Hemodynamic data were recorded with the Biopac MP-100 Data Acquisition system (Biopac Systems, Inc., Santa Barbara, CA) after the ECHO analysis. Mean BP was recorded by cannulating the left carotid artery. During this period, rectal temperature controls were performed at 15 min intervals to keep the body temperature of the rats in the range of 36-37 °C. In cases where body temperatures drop, the body blanket, which is laid under the rats, is run and body temperature is balanced. Three-lead electrocardiographic (ECG) electrodes were also used to record ECG changes. In the JWH-018 administered groups, electrophysiological characteristics and pathologic changes in the ECG trace included ST depression, T-wave negative, heart block, cardiac arrhythmia, and QT prolongation. Arrhythmia variety as well as QT times were calculated using Lambeth Convention criteria once the computer data were completed (26). Blood samples from the inferior vena cava and cardiac tissues were obtained once the test regimen was completed. Since hemodynamic records were taken for 2 hours, blood and heart tissue samples were taken by euthanasia of 4 rats every day. The serums were separated by centrifugation from the blood taken into the gel biochemistry tube. Heart tissue and serum samples were stored in a deep freezer at -80 degrees until biochemical analyzes began.
2.5. Histopathological Analysis
Heart tissue samples were preserved in 10% formaldehyde at the end of the experiment. After routine tissue follow-up the paraffin-embedded samples were cut in 4µ thickness and stained with Hematoxylin and Eosin (H&E). Staining was performed in a Ventana Benchmark XT immunohistochemical staining device (Ventana Medical Systems, Roche Group, Tucson, AZ, USA) to evaluate desmin and caspase-3 antibodies in sections. All staining was evaluated under the light microscope. Semi-quantitative scoring was done between 0-3 for the intensities of desmin staining. Scoring system; 0: no staining, 1: mild staining, 2: moderate staining, 3: severe staining (27).