Effects of vitamin D mediated MEK/ERK pathway on myocardial damage in rats with gestational diabetes mellitus
Objective To investigate the effects of vitamin D mediated mitogen-activated protein kinase(MEK)/extracellular signal-regulated kinase(ERK)pathway on myocardial injury in rats with gestational diabetes mellitus.Methods Fifty SD rats were divided into control group,model group,experimental-L group,experimental-M group and experimental-H group,and the gestational diabetes rat model was established.After successful modeling,experimental-L,experimental-M,experimental-H groups were given intragastric administration of 0.05,0.10 and 0.15 µg·kg-1 concentration of vitamin D,while control group and model group were given intragastric administration of 0.9％NaCl at the same dose once a day for 2 weeks.Fasting blood glucose concentration and insulin level were detected before intervention,1 week and 2 weeks after intervention.Echocardiography was used to detect cardiac function[left ventricular ejection fraction(LVEF),maximum rate of rise(+dp/dtmax)and maximum rate of decline(-dp/dtmax)of left ventricular pressure].Myocardial enzyme indexes[troponin Ⅰ(cTn Ⅰ)kit,creatine kinase isoenzyme(CK-MB)]and inflammatory factors[tumor necrosis factor-α(TNF-α),C-reactive protein(CRP)]in serum and myocardial tissue of rats were detected by enzyme-linked immunosorbent assay(ELISA),and MEK/ERK pathway protein expression was detected by western blot.Results The levels of cTn Ⅰ in cardiac tissue of control group,model group,experimental-L group,experimental-M group,experimental-H group were(10.50±1.08),(42.26±4.30),(31.85±2.44),(23.31±2.15)and(14.85±1.19)ng·mL-1;serum cTn Ⅰ levels were(23.79±3.46),(63.59±5.52),(51.02±4.27),(42.75±3.19)and(29.20±2.11)ng·mL-1;myocardial tissue levels of CK-MB were(8.52±0.90),(17.65±1.75),(15.62±1.27),(13.11±1.24)and(9.85±0.87)ng·mL-1;serum levels of CK-MB were(11.32±0.98),(21.24±1.45),(18.75±1.32),(15.11±1.02)and(12.27±1.11)ng·mL-1;phosphorylated-MEK protein expression were 0.24±0.03,0.85±0.09,0.72±0.06,0.57±0.07 and 0.35±0.04;phosphorylated-ERK1/2 protein expression were 0.18±0.02,0.66±0.07,0.52±0.06,0.40±0.07 and 0.24±0.05,respectively.There were statistically significant differences of above indexes between control group and model group(all P＜0.05);the difference between model group and experimental-L,experimental-M,experimental-H groups were all statistically significant(all P＜0.05).Conclusion Vitamin D may reduce myocardial injury in rats with gestational diabetes by inhibiting the activation of MEK/ERK pathway.
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