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Updated: Jan 20, 2026
TGF - β Signaling Pathway
Effect of miR-9 on myocardial fibrosis in rats via TGF-β1/Smads signaling pathway
1Department of Cardiology, Yantai Hospital of Traditional Chinese Medicine, Yantai, China. yucx05@163.com.
Objective:
To observe the effect of micro ribonucleic acid (miR)-9 on the myocardial fibrosis (MF) in rats and explore its mechanism of action.
Materials And Methods:
A total of 30 rats were selected to prepare the models of MF and randomly divided into Sham group, Model group and MiR-9 group. The rat heart weight (HW)/body weight (BW) and left ventricular weight (LVW)/BW were determined. The content of hydroxyproline (Hyp) in the myocardial tissues of left ventricle was measured using a spectrophotometer. Enzyme-linked immunosorbent assay (ELISA) was performed to determine the levels of type I and type III collagens in myocardial tissues, and the level of miR-9 in myocardial tissues was determined via reverse transcription-polymerase chain reaction (RT-PCR). Finally, Western blotting was conducted to measure the levels of transforming growth factor-β1 (TGF-β1) and Smads2 proteins.
Results:
Compared with Sham group, Model group exhibited increased HW/BW and LVW/BW and markedly raised Hyp content and type I collagen, type III collagen, TGF-β1 protein and Smads2 protein levels, but significantly declined miR-9 expression levels in rats. In MiR-9 group, the rats had substantially decreased HW/BW, LVW/BW, Hyp content, and type I and type III collagen levels as well as lowered TGF-β1 protein and Smads2 protein levels.
Conclusions:
MiR-9 can alleviate the MF in rats by inhibiting the TGF-β1/Smads signaling pathway.
Insights
MicroRNA-9 (miR-9) alleviates myocardial fibrosis in rats by inhibiting the TGF-β1/Smads pathway. This study observed miR-9's effect on cardiac fibrosis and its underlying mechanism.
Area of Science:
- Cardiovascular Biology
- Molecular Medicine
- Fibrosis Research
Background:
- Myocardial fibrosis (MF) is a significant pathological process.
- Understanding the molecular mechanisms regulating MF is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the therapeutic effect of microRNA-9 (miR-9) on myocardial fibrosis in a rat model.
- To elucidate the underlying molecular mechanism of miR-9 in regulating myocardial fibrosis.
Main Methods:
- Myocardial fibrosis was induced in rats.
- Rats were divided into Sham, Model, and miR-9 treatment groups.
- Key indicators measured included heart/body weight ratios, hydroxyproline content, collagen levels (Type I and III), miR-9 expression, and TGF-β1/Smads2 protein levels via RT-PCR and Western blotting.
Main Results:
- Rats with induced myocardial fibrosis showed increased heart/body weight ratios, hydroxyproline, collagen I and III, TGF-β1, and Smads2 levels, alongside decreased miR-9 expression compared to controls.
- miR-9 treatment significantly reversed these pathological changes, reducing fibrosis markers and TGF-β1/Smads2 signaling.
Conclusions:
- MicroRNA-9 (miR-9) demonstrates a protective effect against myocardial fibrosis in rats.
- The mechanism involves the inhibition of the transforming growth factor-β1 (TGF-β1)/Smads signaling pathway.
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