Mechanism of Zuogui Jiangtang Shuxin Formula in inhibiting myocardial fibrosis in mice with diabetic cardiomyopathy by regulating TLR4/NF-κB pathway
Objective To investigate the effects of Zuogui Jiangtang Shuxin Formula(ZGJTSXF)on myocardial fibrosis and inflammatory factors in MKR mice with diabetic cardiomyopathy(DCM)based on the Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB)signaling pathway.Methods Male MKR mice aged 8 weeks were used as experimental subjects.A diabetic cardiomyopathy model was established using a high-fat diet combined with intraperitoneal injection of streptozotocin(STZ)40 mg/kg.The mice were randomized into high-[33.67 g/(kg·d)]and low-dose[16.84 g/(kg·d)]ZGJTSXF groups(containing raw medicinals 2 g/mL),western medicine combination group[metformin 0.23 g/(kg·d)combined with enalapril 1.5 mg/(kg·d)],and model group(equal volume of distilled water);additionally,FVB mice were set as the blank control group(equal volume of distilled water).Each group consisted of 10 mice and samples were collected after 8 weeks of continuous medication.Tail vein blood was collected to test fasting blood glucose levels.Myocardial pathological changes were observed using HE and Masson's trichrome staining,and ultrastructural changes in the myocardial tissue were examined with electron microscopy.ELISA was used to measure the content of tumor necrosis factor-α(TNF-α)and interleukin 1β(IL-1β)of the mice serum.Western blot was used to check the protein expressions of TLR4,NF-κB p56,and p-NF-κB p56/NF-κB p56.RT-qPCR and Western blot were employed to measure the expression levels of collagen type Ⅰ(CollagenⅠ),collagen type Ⅲ(CollagenⅢ),and α-smooth muscle actin(α-SMA)in the myocardial tissue of mice.Results Compared with the blank control group,the model group showed increased fasting blood glucose and serum levels of TNF-α and IL-1β(P<0.01),accompanied by myocardial cell structural disorder,increased collagen content,and severe myocardial cell degeneration;the protein expressions of TLR4,NF-κB p56,and p-NF-κB p56/NF-κB p56 were upregulated in the myocardial tissue(P<0.01),and the mRNA and protein expression levels of Collagen Ⅰ,Collagen Ⅲ,and α-SMA were elevated(P<0.05,P<0.01).Compared with the model group,the high-and low-dose ZGJTSXF groups and the western medicine combination group showed reductions in fasting blood glucose and serum levels of TNF-α and IL-1β(P<0.01),improved myocardial structure,and decreased collagen deposition;the protein expressions of TLR4,NF-κB p56,and p-NF-κB p56/NF-κB p56 were downregulated in the myocardial tissue(P<0.01),as well as the protein and mRNA expressions of Collagen Ⅰ,CollagenⅢ,and α-SMA(P<0.01).Compared with the western medicine combination group,the low-dose ZGJTSXF group exhibited increased fasting blood glucose and serum levels of TNF-α and IL-1β(P<0.01),with no noticeable improvement in myocardial structure and no obvious reduction in collagen deposition;the protein expressions of TLR4,NF-κB p56,and p-NF-κB p56/NF-κB p56 were upregulated in the myocardial tissue(P<0.01),along with increased protein and mRNA expressions of Collagen Ⅰ,Collagen Ⅲ,and α-SMA(P<0.01).Conclusion ZGJTSXF may inhibit myocardial inflammatory response and improve myocardial cell structure.Its mechanism of action may be related to the regulation of TLR4/NF-κB pathway,down-regulation of cellular inflammatory factor expression,and inhibition of myocardial fibrosis.
万方数据
维普
