Objective:To evaluate the effect of baicalein on acute myocardial injury in rats with high-level spinal cord injury (SCI) and the role of nuclear factor E2-related factor 2 (Nrf2).Methods:Twenty-four clean-grade healthy male Sprague-Dawley rats, aged 8-10 weeks, weighing 250-300 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SCI group, SCI+ baicalein group (SCI+ Bai group) and SCI+ baicalein+ ML385 group (SCI+ Bai+ ML385 group). The high-level SCI rat model was established by the modified Allens method. In Sham group, the 7th cervical vertebra (C 7) was only exposed, but the spinal cord was not hit. In SCI group, C 7 was exposed and the spinal cord was hit. In SCI+ Bai group, baicalein 50 mg/kg was intraperitoneally injected immediately after SCI. In SCI+ Bai+ ML385 group, Nrf2 inhibitor ML385 30 mg/kg was intraperitoneally injected at 1 h before SCI, and baicalein 50 mg/kg was intraperitoneally injected immediately after SCI. The rats were anesthetized at 24 h after SCI and sacrificed after the blood samples from the abdominal aorta were collected and the hearts were taken for microscopic examination of the pathological changes (by HE staining) which were scored and the ultrastructure of cells (with a transmission electron microscope) and for determination of the serum cardiac troponin I (cTnI) concentrations (by enzyme-linked immunosorbent assay), content of ferrous ion (Fe 2+ ) in myocardial tissues (by colorimetry), contents of malondialdehyde(MDA) and glutathione (GSH) and activity of superoxide dismutase(SOD) in myocardial tissues (by biochemical method) and expression of glutathione peroxidase 4 (GPX4), acyl CoA synthase long chain family member 4 (ACSl4) and Nrf2 protein and mRNA in myocardial tissues (by Western blot and fluorescent quantitative polymerase chain reaction). The mitochondrial Flameng score was assessed and recorded. Results:Compared with Sham group, the pathological score, mitochondrial Flameng score and serum cTnI concentrations were significantly increased, the contents of Fe 2+ and MDA in myocardial tissues were increased, the content of GSH and SOD activity were decreased, the expression of GPX4 was down-regulated, and the expression of ACSL4 and Nrf2 was up-regulated in SCI group ( P<0.05). Compared with SCI group, the pathological score, mitochondrial Flameng score and serum cTnI concentration were significantly decreased, the contents of Fe 2+ and MDA in myocardial tissues were decreased, the contents of GSH and SOD activity were increased, the expression of GPX4 and Nrf2 was up-regulated, and the expression of ACSL4 was down-regulated in SCI+ Bai group ( P<0.05). Compared with SCI+ Bai group, the pathological score, mitochondrial Flameng score and serum cTnI concentrations were significantly increased, the contents of Fe 2+ and MDA in myocardial tissues were increased, the content of GSH and SOD activity were decreased, the expression of GPX4 and Nrf2 was down-regulated, and the expression of ACSL4 was up-regulated in SCI+ Bai+ ML385 group ( P<0.05). Conclusions:Baicalein can alleviate acute myocardial injury in rats with high-level SCI, and Nrf2 is involved in this process.

Objective:To evaluate the effect of baicalein on acute myocardial injury in rats with high-level spinal cord injury (SCI) and the role of nuclear factor E2-related factor 2 (Nrf2).Methods:Twenty-four clean-grade healthy male Sprague-Dawley rats, aged 8-10 weeks, weighing 250-300 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SCI group, SCI+ baicalein group (SCI+ Bai group) and SCI+ baicalein+ ML385 group (SCI+ Bai+ ML385 group). The high-level SCI rat model was established by the modified Allens method. In Sham group, the 7th cervical vertebra (C 7) was only exposed, but the spinal cord was not hit. In SCI group, C 7 was exposed and the spinal cord was hit. In SCI+ Bai group, baicalein 50 mg/kg was intraperitoneally injected immediately after SCI. In SCI+ Bai+ ML385 group, Nrf2 inhibitor ML385 30 mg/kg was intraperitoneally injected at 1 h before SCI, and baicalein 50 mg/kg was intraperitoneally injected immediately after SCI. The rats were anesthetized at 24 h after SCI and sacrificed after the blood samples from the abdominal aorta were collected and the hearts were taken for microscopic examination of the pathological changes (by HE staining) which were scored and the ultrastructure of cells (with a transmission electron microscope) and for determination of the serum cardiac troponin I (cTnI) concentrations (by enzyme-linked immunosorbent assay), content of ferrous ion (Fe 2+ ) in myocardial tissues (by colorimetry), contents of malondialdehyde(MDA) and glutathione (GSH) and activity of superoxide dismutase(SOD) in myocardial tissues (by biochemical method) and expression of glutathione peroxidase 4 (GPX4), acyl CoA synthase long chain family member 4 (ACSl4) and Nrf2 protein and mRNA in myocardial tissues (by Western blot and fluorescent quantitative polymerase chain reaction). The mitochondrial Flameng score was assessed and recorded. Results:Compared with Sham group, the pathological score, mitochondrial Flameng score and serum cTnI concentrations were significantly increased, the contents of Fe 2+ and MDA in myocardial tissues were increased, the content of GSH and SOD activity were decreased, the expression of GPX4 was down-regulated, and the expression of ACSL4 and Nrf2 was up-regulated in SCI group ( P<0.05). Compared with SCI group, the pathological score, mitochondrial Flameng score and serum cTnI concentration were significantly decreased, the contents of Fe 2+ and MDA in myocardial tissues were decreased, the contents of GSH and SOD activity were increased, the expression of GPX4 and Nrf2 was up-regulated, and the expression of ACSL4 was down-regulated in SCI+ Bai group ( P<0.05). Compared with SCI+ Bai group, the pathological score, mitochondrial Flameng score and serum cTnI concentrations were significantly increased, the contents of Fe 2+ and MDA in myocardial tissues were increased, the content of GSH and SOD activity were decreased, the expression of GPX4 and Nrf2 was down-regulated, and the expression of ACSL4 was up-regulated in SCI+ Bai+ ML385 group ( P<0.05). Conclusions:Baicalein can alleviate acute myocardial injury in rats with high-level SCI, and Nrf2 is involved in this process.