OBJECTIVE:Experimental MI models induced by isoproterenol (ISO) are frequently used because they show many similarities to the human heart attack model. Thymoquinone (THQ) is a biologically active compound known for its antioxidant and anti-inflammatory properties. This study aimed to induce experimental MI using ISO and to investigate the effects of THQ through its relationship with apelin.
METHODS:Control, THQ group, ISO group, THQ + ISO group. THQ was administered orally (20 mg/kg) for 10 days, while ISO was administered at 100 mg/kg every 24 h on days 10 and 11. At the end of the experiment, electrocardiograms were performed on the rats, and blood samples were taken to excise heart tissue. Histopathological scoring, gene expression, and immunohistochemistry were performed on the heart tissue to assess the expression of APJ, apelin-13, AGTR1, and ACE2 proteins. CK-MB, cTn-I, LDH, apelin-36, and ELA were measured in blood serum, and apelin-36 and ELA were measured in heart tissue homogenate using ELISA.
RESULTS:ISO successfully created an MI model, as evidenced by both ECG and CK-MB, cTn-I, and LDH levels. Histopathologically, ISO caused intense fibrosis and inflammatory cell infiltration. APJ, apelin-13, AGTR1, and ACE2 gene expressions and immunoreactivities were decreased in the ISO group. Apelin-36 and ELA levels were also found to be decreased in the ISO group. THQ protected ECG, CK-MB, cTn-I, and LDH levels. Furthermore, it regulated the gene expression levels and immunoreactivities of all markers, especially APJ and apelin-13. It also contributed to the preservation of ELA levels.
CONCLUSION:It has been shown that THQ may exert cardioprotective effects by supporting apelin and apelin-related receptors and other mechanisms. While the short half-lives of apelin and ELA peptides in the bloodstream or extracellular environment limit their use, we suggest that forms and mechanisms that affect the half-life of these peptides should be developed or their use in combination with THQ should be evaluated in the MI model.