Physical exercise combined with prednisolone attenuates serum TNF-α expression in a rat model of epileptic seizures: an experimental and in silico study of candidate regulatory microRNAs.

OBJECTIVES: Epilepsy is frequently associated with neuroinflammation, in which tumor necrosis factor-alpha (TNF-α) promotes excitotoxicity and neuronal hyperexcitability. We evaluated whether physical exercise, alone or combined with prednisolone, modulates peripheral TNF-α mRNA expression in a pentylenetetrazol (PTZ)-induced seizure model, and applied in silico approaches to identify candidate microRNAs (miRNAs) and circular RNAs (circRNAs) potentially regulating TNF-α.

METHODS: Serum from male Wistar rats submitted to a PTZ-seizure and treadmill-exercise protocol (exercise + saline, exercise + prednisolone, sedentary + diazepam, and naïve groups) was analyzed by qRT-PCR using the 2-ΔCt method. Experimentally validated miRNA-TNF-α interactions were retrieved from miRTarBase and TarBase, cross-referenced with IL-1β-targeting miRNAs, and assessed for 3'UTR conservation across mammalian species; competing circRNA interactions were searched in circRNAdisease.

RESULTS: Serum TNF-α expression was lower in the exercise + prednisolone group than in the exercise + saline group (p < 0.05), indicating an additional reduction relative to exercise alone. Twenty-nine miRNAs targeting TNF-α were identified, four of which (hsa-let-7c-5p, hsa-miR-34a-5p, hsa-miR-124-3p, and hsa-miR-149-5p) also targeted IL-1β. hsa-miR-149-5p showed the highest binding-site conservation (92.9%), and no brain-expressed circRNA competing for it was documented in current databases.

DISCUSSION: Among exercised PTZ-treated rats, serum TNF-α mRNA levels were lower in animals receiving prednisolone than in those receiving saline. The in silico findings are hypothesis-generating and highlight hsa-miR-149-5p as a prioritized computational candidate warranting experimental validation.