ABSTRACT
Z-VAD-FMK was combined with hypoxia-reoxygenation (H/R) injury to establish a necroptosis model of H9c2 cells to mimic the pathological changes of myocardial ischemia reperfusion injury (MIRI) in vitro and to study the effect and mechanism of tilianin against myocardial ischemia-reperfusion injury. A cell counting kit-8 (CCK-8) was used to detect cell viability, and commercial kits were used to detect lactate dehydrogenase (LDH) and superoxide dismutase (SOD) in the cell culture supernatant. Hoechst 33342/PI immunofluorescence staining was used to detect cell death. DCFH-DA, BBcellProbeTMM61, and JC-1 probes were used to detect reactive oxygen species (ROS), mitochondrial permeability transition pore (mPTP), and mitochondrial membrane potential (MMP), respectively. An enzyme-linked immunosorbent assay (ELISA) method was used to detect the release of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). The results show that the cell viability, SOD activity, and MMP of the model group induced by H/R injury decreased, as compared with control group, but the necroptosis rate, LDH level, and ROS release increased significantly. Furthermore, mPTP of the model group cells opened, and TNF-α, IL-1β, and IL-6 levels were significantly higher. Molecular docking modeling showed that tilianin can bind to calmodulin-dependent protein kinase II (CaMKII), and Western blot results showed that compared with control group, the expression levels of p-CaMKII and phospho-mixed lineage kinase domain-like protein increased in the model group, and tilianin could decrease the expression level of these proteins. The above results indicate that tilianin can protect H9c2 cells by inhibiting the phosphorylation of CaMKⅡ at threonine 287, protecting mitochondrial function, and inhibiting the opening of mPTP to prevent necroptosis. This study has value for research on new methods to treat H/R injury.
ABSTRACT
Objective: To explore the changes of protein expression and activity of calcium/calmodulin-dependent protein kinase-II (CaMK-II) in myocardium nucleus and sarcoplasmic reticulum in experimental rabbits with heart failure (HF). Methods: A total of 16 rabbits were divided into 2 groups: Sham group and HF group, the HF model was established by volume overload plus pressure overload.n=8 in each group and all animals were treated for 7 weeks. Left ventricular structure, hemodynamic parameters and protein expression and activity of CaMK-II in myocardium nucleus and sarcoplasmic reticulum were examined and compared between 2 groups. Results: Compared with Sham group, HF group presented increased left ventricular mass index (LVMI) (1.32 ± 0.06) g/kg vs (3.61 ± 0.09) g/kg, LVEDP (-1.50 ± 0.50) mmHg vs (23.00 ± 2.37) mmHg, allP Conclusion: Increased protein expression and activity of CaMK-II in myocardium nucleus and sarcoplasmic reticulum might be one of the mechanisms for HF occurrence in experimental rabbits.
ABSTRACT
Objective: To explore the role of calcium/calmodulin-dependent protein kinase-II δ (CaMK-II δ) in doxorubicin (DOX) induced cardio-toxicity in experimental rats. Methods:①The rat’s cardiomyocytes were treated by DOX and the cell proliferation, protein expression and activity of CaMK-II δ were examined.②CaMK-II δ gene was knocked out by CRISPR method, the changes of DOX induced cell apoptosis and NF-κb activity and miR-146a expression were detected. Results: DOX could inhibit cardiomyocyte proliferation, the protein expression level of CaMK-II δ was similar and the activity was increased. CRISPR method may effectively knock out CaMK-II δ gene. Compared with normal cells, the cells from CaMK-II δ knocked out rats had decreased sensitivity to DOX induction, suppressed NF-κb activation and miR-146a up-regulation. Conclusion: CaMK-II δ participated in DOX induced cardio-toxicity in experimental rats and NF-κb and miR-146a were involved in this process.
ABSTRACT
Objective: To investigate the effect of endocannabinoid system on cardiac hypertrophy in experimental rats with chronic intermittent hypoxia and to study the impact of endocannabinoid antagonist, rimonabant in such pathological processing. Methods: A total of 48 male Wistar rats were divided into 6 groups. 4 and 6 weeks of Normal control group, 4 and 6 weeks of Hypoxia group, 4 and 6 weeks of Hypoxia with rimonabant intervention group. n=8 in each group. The rats were sacrificed to measure left ventricular mass index (LVMI), the myocardial cell morphological changes were observed by optical microscope, the expression of cardiac calcium/calmodulin-dependent protein kinase II (CaMKII) and cardiotrophin-1 (CT-1) were detected by immunohistochemistry at 4 and 6 weeks respectively. Results: Compared with 4 and 6 weeks of Normal control group, the LVMI, cardiac hypertrophy condition, CaMKII and CT-1 were increased in 4 and 6 weeks of Hypoxia group, all P Conclusion: The Chronic intermittent hypoxia could induce myocardial hypertrophy via endocannabinoid system disorders, such pathological processing could be reduced by rimonabant intervention.