ABSTRACT
Objective:To evaluate the effect of resveratrol on radiation-induced myocardial injury in mice.Methods:A total of 80 C57BL/6 mice were randomly divided into the control group, resveratrol (Res) group, radiation (RT) group and radiation+resveratrol (RT+Res) group. In the RT group, mice were given with heart radiation and mice in the Res group were given with resveratrol by gavage for 3 months. Cardiac ultrasound was used to evaluate cardiac function at 3 months after cardiac radiation. The hearts of mice were collected for HE staining, immunofluorescence, TUNEL staining, Masson staining and Western blot to evaluate the expression of silent information regulator 1 (SIRT1), the level of oxidative stress, inflammatory response, apoptosis and the degree of fibrosis in myocardial tissues. Experimental data were expressed as Mean ± SD. Continous data were statistically analyzed by t-test. Results:After 3 months of irradiation, compared with the control group, the ejection fraction (EF) and fractional shortening (FS) of cardiac function were decreased, and myocardial degeneration and disorder, reactive oxygen species (ROS) and inflammatory levels (interleukin-1β, interleukin-6, tumor necrosis factor-α), myocardial apoptosis (TUNEL positive cell rate) and fibrosis were increased in the RT group. In the RT+Res group, the cardiac function was improved, the expression of SIRT1 was increased, and the levels of oxidative stress, inflammation, myocardial apoptosis and fibrosis were decreased.Conclusions:Resveratrol can reduce oxidative stress, inflammatory infiltration, apoptosis and fibrosis of myocardium in mice with radiation-induced myocardial injury, thereby improving cardiac structural abnormalities and cardiac dysfunction. This protective effect can be mediated by upregulation of SIRT1 expression.
ABSTRACT
Objective:To observe the expression of sirtuin 3 (Sirt3) and mitochondrial damage-associated proteins in lipopolysaccharide (LPS)-induced acute kidney injury mouse model and renal tubular epithelial cells, and to explore the role of Sirt3 in LPS-induced abnormal mitochondrial dynamics in renal tubular epithelial cells.Methods:Eighteen specific pathogen free (SPF) male C57BL/6 mice were randomly assigned to control group, LPS 24 h group and LPS 48 h group. The control group was intraperitoneally injected with physiological saline (0.1 ml/10 g), and LPS 24 h group and LPS 48 h group were intraperitoneally injected with LPS (10 mg/kg) solution. Renal functional indexes of mice were analyzed by automatic biochemical analyzer. The pathological change of the kidney was observed by HE staining, and the expressions of dynamin-related protein-1 (Drp1), optic atrophy type 1 (Opa1) and Sirt3 were evaluated by Western blotting. Expression and distribution of Sirt3 in kidney was assessed by immunohistochemistry. Human renal tubular epithelial cells (HK-2) were exposed to 10 μg/ml LPS for 24 h, and the expression of Drp1, Opa1 and Sirt3 were detected by Western blotting. Cell apoptosis was assessed by Hoechst-33342 staining. After transfection to HK-2 cells with pcDNA3.1-Sirt3 recombinant plasmid, the expressions of Sirt3, Drp1, Opa1 and cell apoptosis were detected by the same methods as above.Results:(1) The levels of blood urea nitrogen and serum creatinine in LPS group were significantly higher than those in control group (both P<0.05), and the pathological changes of kidney were obvious. (2) Compared with the control group, the expression of mitochondrial fission-associated protein Drp1 in renal tissue of LPS group was significantly higher ( P<0.05), and the expression of mitochondrial fusion associated protein Opa1 was significantly lower ( P<0.05). (3) Compared with the control group, the expression of Sirt3 in LPS group was significantly lower ( P<0.05), and immunohistochemistry results showed that Sirt3 was mainly expressed in glomerular vascular endothelial cells and renal tubular epithelial cells. (4) In vitro, LPS stimulation induced increased Drp1 expression in HK-2 cells ( P<0.05), decreased Opa1 and Sirt3 expression (both P<0.05), and increased apoptosis ( P<0.05). (5) LPS-induced mitochondrial dynamics disturbance and apoptosis were alleviated by pcDNA3.1-Sirt3 recombinant plasmid transfection. Conclusions:LPS can induce down-regulation of Sirt3 expression and disturbance of mitochondrial dynamics, and Sirt3 may play a protective role in LPS-induced acute kidney injury by regulating mitochondrial dynamics.