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Document Type

Abstract

Publication Date

1-14-2026

Abstract

Myocardial fibrosis is an important pathological feature of cardiovascular aging, and a high-fat diet (HFD) can accelerate its progression, while SPARC, a remodeling-related protein, may mediate this mechanism. Endurance exercise has been shown to have cardioprotective effects, but its regulatory mechanism on age-related myocardial fibrosis induced by a high-fat diet is still unclear. This study aims to explore whether endurance exercise improves the cardiac fibrosis phenotype in high-fat-fed fruit flies by downregulating SPARC expression and elucidates its underlying molecular mechanisms. Method: Wild-type female fruit flies (n=400) within 12 hours of feathering were selected and randomly divided into four groups (n=100 per group): 10-day-old normal diet control (10D-NC), 10-day-old high-fat diet (10D-HFD), 40-day-old normal diet (40D-NC), and 10-day-old high-fat diet and exercise (10D-HE). The NC group continued to feed normal feed (including yeast, corn, and starch). The HFD group and the HE group received high-fat feed with 30% coconut oil (volume ratio) for 5 days from 5 days old. The HE group performed 2.5 hours of endurance exercise daily from 5 days of age until 10 days of age. 24 hours after the intervention, RT-qPCR was used to detect the expression level of SPARC mRNA in the heart tissue, and cardiac pulsation was recorded by an EM-CCD camera (130 frames/s). The cardiac functional parameters, such as heart rate, cardiac cycle, systolic interval, arrhythmia index, diastolic diameter, and shortening fraction, were quantified in combination with semi-automatic optical analysis software. Compared with the 10D-NC group, the expression of cardiac SPARC in the 10D-HFD group was significantly upregulated (P < 0.01), accompanied by accelerated heart rate (P < 0.001), prolonged cardiac cycle (P < 0.05), increased arrhythmia index (P < 0.001), and decreased shortening score (P < 0.001); compared with the 10D group, the expression of cardiac SPARC in the 40D group was significantly upregulated (P < 0.001), accompanied by accelerated heart rate (P < 0.001), prolonged cardiac cycle (P < 0.001), increased arrhythmia index (P < 0.05), and decreased shortening score (P < 0.05). Compared with the HFD group, SPARC expression in the HE group was significantly downregulated (P < 0.01), heart rate slowing (P < 0.001), shortening of cardiac cycle (P < 0.05), prolonging of systolic interval (P < 0.05), decreased arrhythmia index (P < 0.001), increased diastolic diameter (P < 0.05), and improved shortening score (P < 0.001). There was no statistical difference between the HE groups and the NC group in SPARC expression and various cardiac function indicators (heart rate, ejection fraction, etc.>0.05. Endurance exercise reduces the deposition of cardiac collagen and prevents myocardial fibrosis and dysfunction in Drosophila in HFD.

DOI

https://doi.org/10.18122/ijpah.5.1.75.boisestate

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