Downregulation of fibromodulin attenuates inflammatory signaling and atrial fibrosis in spontaneously hypertensive rats with atrial fibrillation via inhibiting TLR4/NLRP3 signaling pathway

Figures

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  Figure 1. Expression levels of fibromodulin (FMOD) in various rat groups. (A) The relative mRNA expression levels of FMOD in atrial tissues of rats were measured by reverse transcription polymerase chain reaction (RT‐qPCR) 1 week after atrial fibrillation (AF) establishment. Normal group: n = 7; Normal‐AF group: n = 3; Spontaneously hypertensive rats (SHR) group: n = 5; SHR‐AF group: n = 6. (B, C) Protein expression levels of FMOD in atrial tissues of rats were measured using Western blot analysis and immunohistochemistry (IHC) 1 week after AF establishment. n = 3. ***p < .001.

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  Figure 2. Fibromodulin (FMOD) expression was downexpressed in fibroblasts. (A) The relative mRNA expression levels of FMOD in fibroblasts after transfection with si‐FMOD were measured by RT‐qPCR. (B) GFP expression in fibroblasts visualized under a fluorescence microscope 24 h after infection with sh‐FMOD or sh‐NC. (C) FMOD mRNA expression in sh‐FMOD and sh‐NC groups was measured by RT‐qPCR. (D) FMOD protein level in sh‐FMOD and sh‐NC groups was measured by Western blot analysis. *p < .05, **p < .01, ***p < .001.

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  Figure 3. Fibromodulin (FMOD) expression was reduced in the SHR‐AF model 8 weeks after sh‐FOMD adenovirus injection. (A) The relative mRNA expression levels of FMOD in atrial tissues of rats was measured by reverse transcription polymerase chain reaction (RT‐qPCR) 8 weeks after adenovirus injection. Spontaneously hypertensive rats (SHR): n = 5; SHR‐AF, SHR‐AF + sh‐NC, and SHR‐AF+sh‐FMOD groups: n = 6. (B and C) The protein expression levels of FMOD in atrial tissues of rats were measured by Western blot analysis and immunohistochemistry (IHC) 8 weeks after adenovirus injection. n = 3. (***p < .001).

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  Figure 4. Fibromodulin (FMOD) knockdown can improve the pathology in SHR‐AF rats. Pathological changes in the atrium were assessed using hematoxylin and eosin (H&E), Masson's, and Picrosirius red staining 8 weeks after sh‐FOMD adenovirus injection.

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  Figure 5. Fibromodulin (FMOD) knockdown can improve the cardiac function in SHR‐AF rats. Schematic diagram of echocardiography results 8 weeks after sh‐FOMD adenovirus injection. Representative images of the echocardiographic measurement are shown. Left atrial diameter is presented as the mean ± standard deviation. Spontaneously hypertensive rats (SHR): n = 5; SHR‐AF, SHR‐AF + sh‐NC, and SHR‐AF + sh‐FMOD groups: n = 6. *p < .05, **p < .01, ***p < .001.

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  Figure 6. Fibromodulin (FMOD) knockdown can silence the TLR4/MyD88/NLRP3 in SHR‐AF rats. (A) Expression of TLR4, MyD88, and NLRP3 mRNAs in atrial tissues were measured via RT‐qPCR 8 weeks after sh‐FOMD adenovirus injection. Spontaneously hypertensive rats (SHR): n = 5; SHR ‐AF, SHR‐AF + sh‐NC, and SHR‐AF + sh‐FMOD groups: n = 6. (B) Protein expression levels of TLR4, MyD88, NLRP3, cleavage‐caspase‐1, and cleavage‐IL‐1β in atrial tissues were measured via western blot analysis 8 weeks after sh‐FOMD adenovirus injection. n = 3. ***p < .001. C‐Caspase‐1, Cleavage‐Caspase‐1; C‐IL‐1β, Cleavage‐IL‐1β.

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  Figure 7. FOMD knockdown can silence the TGF‐β1/Smad and inhibit fibrosis in SHR‐AF rats. (A) Expression of TGF‐β1, collagen I, and collagen II mRNAs in atrial tissues were measured via RT‐qPCR 8 weeks after sh‐FOMD adenovirus injection. SHR: n = 5; SHR‐AF, SHR‐AF + sh‐NC, and SHR‐AF + sh‐FMOD groups: n = 6. (B) Protein expression levels of TGF‐β1, p‐Smad2, Smad2, collagen I, and collagen II in atrial tissues were measured via Western blot analysis 8 weeks after sh‐FOMD adenovirus injection. n = 3. ***p < .001.