Melatonin Promotes Neurogenesis via the JAK2/STAT3 Pathway in Hypoxic-Ischemic Neonatal Rats

Neonatal hypoxic-ischemic brain damage (HIBD) is a leading cause of neurological dysfunction and long-term disability in newborns. Lactate accumulation and metabolic disturbances after brain injury inhibit neurogenesis, while the restorative capacity of endogenous neural stem cells (NSCs) is essential for neural reconstruction. Melatonin (Mel) alleviates neonatal brain injury, but its effects on NSCs proliferation and migration remain unclear, and the visualization methods for dynamic monitoring of metabolic changes are inadequate. In this study, a neonatal rat model of HIBD was established, and multimodal MRI combined with histological techniques was employed to evaluate the effects of Mel on NSCs regeneration and metabolic conditions in the hippocampal dentate gyrus. Using these techniques, the potential neuroprotective effects of Mel via the JAK2/STAT3 pathway were investigated. Multimodal MRI revealed that Mel increased cerebral blood flow and oxygen saturation, reduced lactate levels, improved brain metabolic microenvironment, and alleviated brain damage caused by HIBD. EdU/Nestin and EdU/DCX staining revealed that Mel promoted the proliferation and migration of endogenous NSCs, thereby enhancing neurogenesis. In addition, the use of a JAK2 inhibitor (WP1066) and agonist (C-A1) verified that Mel exerted its protective effects by down-regulating the JAK2/STAT3 pathway. Morris water maze further confirmed that Mel improved spatial learning and memory function in neonatal rats with HIBD. Multimodal MRI offers a visual basis for monitoring metabolic changes and therapeutic effects, while Mel enhances neurogenesis and mitigates brain injury through inhibition of the JAK2/STAT3 pathway, thus providing a theoretical basis for the clinical application of Mel in HIBD in neonates.