Objective:To explore the cardioprotective effects of icariin (ICA) against radiation-induced cardiac disease (RICD) in C57BL/6 mice.Methods:A total of 48 female C57BL/6J mice aged 6-8 weeks were randomly divided into three groups: the control group (CON), the irradiation group (IR), and the irradiation combined with icariin group (IR+ ICA), with 16 mice in each group. The IR and IR+ ICA groups received a single cardiac irradiation at a dose of 30 Gy, while the CON group received no radiation treatment. The IR+ ICA group was treated with ICA (70 mg·kg -1·d -1) two weeks before irradiation until the end of the experiment through intragastric administration. In contrast, the CON and IR groups were treated with an equal volume of vehicle solution (0.5% sodium carboxymethyl cellulose, NaCMC) via intragastric administration. The mice′s mental status, food intake, body weight, and survival rates were monitored during the experiment. At two weeks post-irradiation, the venous blood of the mice was collected and serum was separated for the enzyme-linked immunosorbent assays (ELISA) of creatine kinase MB isoenzyme (CK-MB) and cardiac troponin T (cTnT/TNNT2). At 12 weeks post-irradiation, the cardiac function of the mice was assessed using echocardiography. After the mice were euthanized under anesthesia, the histopathological changes and fibrosis degree of their myocardial tissues were assessed using hematoxylin and eosin (HE) and Masson′s trichrome staining, followed by the calculation of collagen volume fraction (CVF). The differential gene expression of brain natriuretic peptide (BNP), transforming growth factor-β (TGF-β), and interleukin-6 (IL-6) in the cardiac tissues of the mice was detected using real-time reverse transcription-polymerase chain reaction (RT-PCR). Apoptosis-related proteins and proteins associated with the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway were determined using Western blotting. The survival curves of the mice were plotted using Kaplan-Meier, and the survival differences of the mice among various groups were compared using the log-rank test. Results:After irradiation, the mice in the IR group showed lethargy, as well as decreased food intake and activity, while these symptoms in the IR+ ICA group were significantly alleviated. At two weeks post-irradiation, the CK-MB and cTnT levels of the IR group were significantly elevated compared with the CON group ( t = 5.28, 8.89, P < 0.01). At 12 weeks post-irradiation, the mice in the IR group exhibited significantly decreased body weight ( t = 2.47, P < 0.05) and decreased survival rates ( HR = 8.25, 95% CI: 1.157-58.770, P < 0.05) compared with the CON group. Echocardiography revealed that the IR group featured decreased left ventricular ejection fraction (EF), decreased fractional shortening (FS), and increased left ventricular end-diastolic diameter (LVDD) compared with the CON group ( t = 7.02, 4.45, P < 0.05). Histopathological examination revealed that the IR group suffered from cardiomyocyte edema, disordered arrangement, and increased fibrosis, with an elevated CVF. The IR group exhibited significantly upregulated gene expression of BNP, TGF-β, and IL-6 in cardiac tissues compared with the CON group ( t = 4.23, 6.39, 4.61, P < 0.05). After-irradiation, the IR group exhibited upregulated apoptosis-related proteins Cleaved Caspase-3 and Bax ( t = 6.29, 9.54, P < 0.05), decreased Bcl-2 expression ( t = 8.20, P < 0.001), and decreased phosphorylation levels of PI3K and Akt ( t = 6.47, 3.42, P < 0.001). The symptoms of the mice were partially ameliorated after treatment with ICA. Specifically, the mice in the IR+ ICA group exhibited higher body weight ( t = 5.13, P < 0.001) and significantly higher survival rates ( HR = 0.121, 95% CI: 0.017-0.864, P < 0.05) than the IR group. Compared to the IR group, the IR+ ICA group showed elevated cardiac function indicators EF and FS( t = 3.23, 3.05, P < 0.05), and reduced LVDD ( t = 3.02, P < 0.05). The histopathological analysis revealed mitigated edema and disordered arrangement of cardiomyocytes in the IR+ ICA group. Furthermore, the IR+ ICA group exhibited significantly lower BNP, TGF-β, and IL-6 expression levels than the IR group ( t = 2.83, 4.15, 2.96, P < 0.05). The expression of apoptosis-related proteins Cleaved Caspase-3 and Bax was lower ( t = 3.23, 3.24, P < 0.05), Bcl-2 expression was higher ( t = 5.92, P < 0.001), and restored phosphorylation levels of PI3K and Akt ( t = 2.89, 8.35, P < 0.001). Conclusions:Icariin has protective effects against the RICD. It alleviates cardiomyocyte apoptosis possibly by upregulating the phosphorylation levels of PI3K and Akt.

Objective:To explore the cardioprotective effects of icariin (ICA) against radiation-induced cardiac disease (RICD) in C57BL/6 mice.Methods:A total of 48 female C57BL/6J mice aged 6-8 weeks were randomly divided into three groups: the control group (CON), the irradiation group (IR), and the irradiation combined with icariin group (IR+ ICA), with 16 mice in each group. The IR and IR+ ICA groups received a single cardiac irradiation at a dose of 30 Gy, while the CON group received no radiation treatment. The IR+ ICA group was treated with ICA (70 mg·kg -1·d -1) two weeks before irradiation until the end of the experiment through intragastric administration. In contrast, the CON and IR groups were treated with an equal volume of vehicle solution (0.5% sodium carboxymethyl cellulose, NaCMC) via intragastric administration. The mice′s mental status, food intake, body weight, and survival rates were monitored during the experiment. At two weeks post-irradiation, the venous blood of the mice was collected and serum was separated for the enzyme-linked immunosorbent assays (ELISA) of creatine kinase MB isoenzyme (CK-MB) and cardiac troponin T (cTnT/TNNT2). At 12 weeks post-irradiation, the cardiac function of the mice was assessed using echocardiography. After the mice were euthanized under anesthesia, the histopathological changes and fibrosis degree of their myocardial tissues were assessed using hematoxylin and eosin (HE) and Masson′s trichrome staining, followed by the calculation of collagen volume fraction (CVF). The differential gene expression of brain natriuretic peptide (BNP), transforming growth factor-β (TGF-β), and interleukin-6 (IL-6) in the cardiac tissues of the mice was detected using real-time reverse transcription-polymerase chain reaction (RT-PCR). Apoptosis-related proteins and proteins associated with the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway were determined using Western blotting. The survival curves of the mice were plotted using Kaplan-Meier, and the survival differences of the mice among various groups were compared using the log-rank test. Results:After irradiation, the mice in the IR group showed lethargy, as well as decreased food intake and activity, while these symptoms in the IR+ ICA group were significantly alleviated. At two weeks post-irradiation, the CK-MB and cTnT levels of the IR group were significantly elevated compared with the CON group ( t = 5.28, 8.89, P < 0.01). At 12 weeks post-irradiation, the mice in the IR group exhibited significantly decreased body weight ( t = 2.47, P < 0.05) and decreased survival rates ( HR = 8.25, 95% CI: 1.157-58.770, P < 0.05) compared with the CON group. Echocardiography revealed that the IR group featured decreased left ventricular ejection fraction (EF), decreased fractional shortening (FS), and increased left ventricular end-diastolic diameter (LVDD) compared with the CON group ( t = 7.02, 4.45, P < 0.05). Histopathological examination revealed that the IR group suffered from cardiomyocyte edema, disordered arrangement, and increased fibrosis, with an elevated CVF. The IR group exhibited significantly upregulated gene expression of BNP, TGF-β, and IL-6 in cardiac tissues compared with the CON group ( t = 4.23, 6.39, 4.61, P < 0.05). After-irradiation, the IR group exhibited upregulated apoptosis-related proteins Cleaved Caspase-3 and Bax ( t = 6.29, 9.54, P < 0.05), decreased Bcl-2 expression ( t = 8.20, P < 0.001), and decreased phosphorylation levels of PI3K and Akt ( t = 6.47, 3.42, P < 0.001). The symptoms of the mice were partially ameliorated after treatment with ICA. Specifically, the mice in the IR+ ICA group exhibited higher body weight ( t = 5.13, P < 0.001) and significantly higher survival rates ( HR = 0.121, 95% CI: 0.017-0.864, P < 0.05) than the IR group. Compared to the IR group, the IR+ ICA group showed elevated cardiac function indicators EF and FS( t = 3.23, 3.05, P < 0.05), and reduced LVDD ( t = 3.02, P < 0.05). The histopathological analysis revealed mitigated edema and disordered arrangement of cardiomyocytes in the IR+ ICA group. Furthermore, the IR+ ICA group exhibited significantly lower BNP, TGF-β, and IL-6 expression levels than the IR group ( t = 2.83, 4.15, 2.96, P < 0.05). The expression of apoptosis-related proteins Cleaved Caspase-3 and Bax was lower ( t = 3.23, 3.24, P < 0.05), Bcl-2 expression was higher ( t = 5.92, P < 0.001), and restored phosphorylation levels of PI3K and Akt ( t = 2.89, 8.35, P < 0.001). Conclusions:Icariin has protective effects against the RICD. It alleviates cardiomyocyte apoptosis possibly by upregulating the phosphorylation levels of PI3K and Akt.