Melatonin modulates the aggravation of pyroptosis, necroptosis, and neuroinflammation following cerebral ischemia and reperfusion injury in obese rats

Obesity is well-established as a common comorbidity in ischemic stroke. The increasing evidence has revealed that it also associates with the exacerbation of brain pathologies, resulting in increasingly severe neurological outcomes following cerebral ischemia and reperfusion (I/R) damage. Mechanistically, pyroptosis and necroptosis are novel forms of regulated death that relate to the propagation of inflammatory signals in case of cerebral I/R. Previous studies noted that pyroptotic and necroptotic signaling were exacerbated in I/R brain of obese animals and led to the promotion of brain tissue injury. This study aimed to investigate the roles of melatonin on pyroptosis, necroptosis, and pro-inflammatory pathways occurring in the I/R brain of obese rats. Male Wistar rats were given a high-fat diet for 16 weeks to induce the obese condition, and then were divided into 4 groups: Sham-operated, I/R treated with vehicle, I/R treated with melatonin (10 mg/kg), and I/R treated with glycyrrhizic acid (10 mg/kg). All drugs were administered via intraperitoneal injection at the onset of reperfusion. The development of neurological deficits, cerebral infarction, histological changes, neuronal death, and glial cell hyperactivation were investigated. This study revealed that melatonin effectively improved these detrimental parameters. Furthermore, the processes of pyroptosis, necroptosis, and inflammation were all diminished by melatonin treatment. A summary of the findings is that melatonin effectively reduces ischemic brain pathology and thereby improves post-stroke outcomes in obese rats by modulating pyroptosis, necroptosis, and inflammation.