We purchased forty-eight 3-week-old male C57BL/6N mice from Beijing HFK Bioscience Co. Ltd. and gave a twelve-hour light and dark cycle starting from 06:00 (am) to 18:00 (pm). Mice were randomly assigned into three groups after 2 weeks of adaptive feeding as follows. (1) The control group (n = 16): mice were provided with normal drinking water, a normal diet and intraperitoneal administration of solvent (5% DMSO + 40% Peg300 + 5% Tween 80 + 50% ddH2O) 3 mL/kg once a week aged 13 to 17 weeks. (2) The HFpEF group (n = 16): a double-hit model was designed, in which metabolic and mechanical stress worked together and resulted in HFpEF. Briefly, C57BL/6N mice had unrestricted access to a high-fat diet (HFD, D12492, Research Diet) starting from 5 weeks old. Meanwhile, a nitric oxide synthase inhibitor, N (gamma)-nitro-L-arginine methyl ester (L-NAME) (N5751, Sigma) was supplied in drinking water (0.5 g/L) for HFpEF groups, and the pH of the drinking water was adjusted to 7.4. The above placebo solvent was administrated in the same manner. (3) The HFpEF + Levo group (n = 16): according to the previous study, HFpEF mice received 3 mg/kg levosimendan (S2446, Selleck) (Dissolve 1 mg of levosimendan in 50 uL of DMSO, subsequently dilute to 1 mg/mL with the above solvent) intraperitoneally once a week from week 13 to 17.

We purchased forty-eight 3-week-old male C57BL/6N mice from Beijing HFK Bioscience Co. Ltd. and gave a twelve-hour light and dark cycle starting from 06:00 (am) to 18:00 (pm). Mice were randomly assigned into three groups after 2 weeks of adaptive feeding as follows. (1) The control group (n = 16): mice were provided with normal drinking water, a normal diet and intraperitoneal administration of solvent (5% DMSO + 40% Peg300 + 5% Tween 80 + 50% ddH2O) 3 mL/kg once a week aged 13 to 17 weeks. (2) The HFpEF group (n = 16): a double-hit model was designed, in which metabolic and mechanical stress worked together and resulted in HFpEF. Briefly, C57BL/6N mice had unrestricted access to a high-fat diet (HFD, D12492, Research Diet) starting from 5 weeks old. Meanwhile, a nitric oxide synthase inhibitor, N (gamma)-nitro-L-arginine methyl ester (L-NAME) (N5751, Sigma) was supplied in drinking water (0.5 g/L) for HFpEF groups, and the pH of the drinking water was adjusted to 7.4. The above placebo solvent was administrated in the same manner. (3) The HFpEF + Levo group (n = 16): according to the previous study, HFpEF mice received 3 mg/kg levosimendan (S2446, Selleck) (Dissolve 1 mg of levosimendan in 50 uL of DMSO, subsequently dilute to 1 mg/mL with the above solvent) intraperitoneally once a week from week 13 to 17.

We purchased forty-eight 3-week-old male C57BL/6N mice from Beijing HFK Bioscience Co. Ltd. and gave a twelve-hour light and dark cycle starting from 06:00 (am) to 18:00 (pm). Mice were randomly assigned into three groups after 2 weeks of adaptive feeding as follows. (1) The control group (n = 16): mice were provided with normal drinking water, a normal diet and intraperitoneal administration of solvent (5% DMSO + 40% Peg300 + 5% Tween 80 + 50% ddH2O) 3 mL/kg once a week aged 13 to 17 weeks. (2) The HFpEF group (n = 16): a double-hit model was designed, in which metabolic and mechanical stress worked together and resulted in HFpEF. Briefly, C57BL/6N mice had unrestricted access to a high-fat diet (HFD, D12492, Research Diet) starting from 5 weeks old. Meanwhile, a nitric oxide synthase inhibitor, N (gamma)-nitro-L-arginine methyl ester (L-NAME) (N5751, Sigma) was supplied in drinking water (0.5 g/L) for HFpEF groups, and the pH of the drinking water was adjusted to 7.4. The above placebo solvent was administrated in the same manner. (3) The HFpEF + Levo group (n = 16): according to the previous study, HFpEF mice received 3 mg/kg levosimendan (S2446, Selleck) (Dissolve 1 mg of levosimendan in 50 uL of DMSO, subsequently dilute to 1 mg/mL with the above solvent) intraperitoneally once a week from week 13 to 17.

We purchased forty-eight 3-week-old male C57BL/6N mice from Beijing HFK Bioscience Co. Ltd. and gave a twelve-hour light and dark cycle starting from 06:00 (am) to 18:00 (pm). Mice were randomly assigned into three groups after 2 weeks of adaptive feeding as follows. (1) The control group (n = 16): mice were provided with normal drinking water, a normal diet and intraperitoneal administration of solvent (5% DMSO + 40% Peg300 + 5% Tween 80 + 50% ddH2O) 3 mL/kg once a week aged 13 to 17 weeks. (2) The HFpEF group (n = 16): a double-hit model was designed, in which metabolic and mechanical stress worked together and resulted in HFpEF. Briefly, C57BL/6N mice had unrestricted access to a high-fat diet (HFD, D12492, Research Diet) starting from 5 weeks old. Meanwhile, a nitric oxide synthase inhibitor, N (gamma)-nitro-L-arginine methyl ester (L-NAME) (N5751, Sigma) was supplied in drinking water (0.5 g/L) for HFpEF groups, and the pH of the drinking water was adjusted to 7.4. The above placebo solvent was administrated in the same manner. (3) The HFpEF + Levo group (n = 16): according to the previous study, HFpEF mice received 3 mg/kg levosimendan (S2446, Selleck) (Dissolve 1 mg of levosimendan in 50 uL of DMSO, subsequently dilute to 1 mg/mL with the above solvent) intraperitoneally once a week from week 13 to 17.