Therapeutic efficacy of 4-hydroxyisoleucine in experimental rat model of demyelination: Neuroprotection through IGF-1 and GLP-1 level restoration.

BACKGROUND: Multiple Sclerosis (MS) is a chronic autoimmune neurodegenerative condition causing demyelination and axonal damage. Ethidium bromide (EBrD) induces focal demyelination by damaging glial cells, especially oligodendrocytes and astrocytes. 4-hydroxyisoleucine (4-HI) exhibits neuroprotective potential by regulating key signaling pathways. To our knowledge, this is the first study assessing the neuroprotective potential of 4-HI in an experimental rat model of demyelination. OBJECTIVE: This study aims to evaluate the neuroprotective potential of 4-HI in an EBrD-induced experimental rat model of demyelination. METHODS: Adult Wistar rats received EBrD injection into the intracerebropeduncle region (ICP) to induce demyelination. Animals were administered 4-HI orally at a dose of 100 or 200 mg/kg and semaglutide at 2 mg/kg. Neurobehavioral performance, pro-inflammatory cytokines, apoptotic markers, neurotransmitter levels, and hematological indices were assessed. Histopathological analysis was conducted to evaluate myelin damage, neuroinflammation, and myelin repair. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to examine IGF-1 and GLP-1 signaling. Further, molecular docking studies were performed to predict 4-HI interactions with IGF-1R and GLP-1R. RESULTS: The study found that 4-HI treatment improved neuromuscular coordination, locomotion, and cognitive function. It reduced pro-inflammatory cytokines, pro-apoptotic markers, and restored neurotransmitter imbalances. Histopathological analysis revealed enhanced myelin repair, reduced neuroinflammation, normalized hematological profiles, and mitigated pathological alterations in various brain regions. Additionally, qRT-PCR showed that 4-HI administration modulated mRNA expression of IGF-1, GLP-1, and cytokines. CONCLUSION: 4-HI exhibits neuroprotective potential in the EBrD-induced demyelination by targeting IGF-1 and GLP-1 pathways, reducing neuroinflammation, restoring myelin integrity, and improving neurobehavioral outcomes. Our findings suggest that 4-HI holds therapeutic potential in demyelination, though further validation is needed.