[Mechanism of protective effect of metformin against septic cardiomyopathy based on the P38 MAPK/JNK signaling pathway].

Exploring the protective mechanism of metformin against septic cardiomyopathy based on the mitogen-activated protein kinase P38 (P38 MAPK)/c-Jun amino-terminal kinase (JNK) signaling pathway. This paper is an experimental animal study design, which was completed from January to December 2023 at the Xiangya Hospital, Central South University. Forty-eight 8-week-old female C57BL/6 mice were divided into four groups: group A (control group), group B (model group), group C (model+trimetazidine hydrochloride), and group D (model+metformin group), with 12 mice in each group, by using a randomized numeric table method. Groups B, C, and D were injected intraperitoneally with LPS (15 mg/kg) to construct a septic cardiomyopathy mouse model. 24 h after modeling, Groups A and B were injected intraperitoneally with an equal amount of saline, Group C was given 20 mg/kg trimetazidine hydrochloride by gavage, and Group D was injected with metformin 200 mg/kg intraperitoneally, and all of them were subjected to consecutive interventions for 14 d. The results were summarized in the following table. Ultrasound imaging system was used to detect cardiac function, and TUNEL method was used to detect apoptosis rate of myocardial tissues; real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the levels of mRNA of JNK, P38 MAPK of P38 MAPK signaling pathway in the myocardial tissues of mice; Plasma creatine kinase isoenzyme (CK-MB), brain natriuretic peptide (BNP), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6) levels were measured by enzyme-linked immunosorbent assay (ELISA) in all groups of mice; and protein kinase C, and protein kinase C levels were measured by protein blotting in cardiac muscle tissue. Eplison isoform (PKCε), and Cavity protein-3 (Cav-3) protein expression in myocardial tissues. The results showed that compared with group A, left ventricular ejection fraction (LVEF) (79.51±6.62)%, left ventricular short-axis shortening (FS) (45.66±4.13), apoptosis rate (4.34±0.36)%, JNK (0.96±0.06), P38 MAPK (1.01±0.03), CK-MB (2.37±0.13) μg/L, BNP (21.36±3.47) ng/L, TNF-α (176.22±19.24) ng/L, IL-6 (35.43±3.84) ng/L, PKCε expression (1.98±0.26), Cav-3 expression (1.04±0.03) compared to apoptosis rates in groups B, C, and D (28.22±4.49, 22.45±3.69, 15.88±3.27), JNK (1.68±0.11, 1.32±0.18, 1.13±0.14), P38 MAPK (2.47±0.71,1.77±0.35,1.49±0.05), CK-MB (16.55±2.16, 12.63±1.98, 5.27±0.61), BNP (48.92±5.67, 33.78±4.11, 27.55±3.84), TNF-α (463.71±24.81, 335.71±36.71, 214.78±22.53), and IL-6 (78.57±6.36, 63.71±5.66, 52.47±5.47) expression were elevated, while left ventricular ejection fraction (LVEF) (49.38±5.27, 55.47±5.03, 62.26±5.14), left ventricular short-axis shortening (FS) (24.36±2.17, 30.43±3.29, 33.57±2.72), PKCε expression (1.33±0.21, 1.54±0.23, 1.75±0.22), and Cav-3 expression (0.47±0.06, 0.76±0.05, 0.85±0.04) were all down-regulated (F=113.020,67.657,219.539,206.222,227.977,88.455,6285.186,135.877,65.924,96.362,17.532,314.419,P<0.05). Compared with group B, apoptosis rate, JNK, P38 MAPK, CK-MB, BNP, TNF-α, and IL-6 expression were decreased, and LVEF, FS, PKCε, and Cav-3 expression were up-regulated in groups C and D. And group D was better than group C (P<0.05). In conclusion, metformin has a protective effect against septic cardiomyopathy, and the mechanism may be related to the inhibition of the activation of the P38 MAPK/JNK signaling pathway and the up-regulation of PKCε and Cav-3 expression.