Oxymatrine Extends Survival by Attenuating Neuroinflammation in a Mouse Model of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is one of the leading causes of death associated with neurodegenerative diseases worldwide, and the progression of the disease is characteristically accompanied by severe neuroinflammation. Neuroprotective effects of oxymatrine (OMT) were shown to be due to reduced neuroinflammation in the mouse models of Alzheimer's disease and Parkinson's disease. The present study investigated whether OMT has a therapeutic potential in transgenic SOD1-G93A (TgSOD1-G93A) mice. Daily OMT treatment started at the age of 55 days until the end stage of the disease. Body weight and rotarod motor performance were assessed every 3 days starting from 70 days of age. Footprints were recorded to measure the stride length 40 days and 60 days after the initiation of the treatment. Some animals were sacrificed at the age of 115 days, and the lumbar spinal cord was harvested for immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR) to evaluate the neuroinflammatory responses. The results indicated that treatment with OMT delayed body weight loss, improved motor performance, and prolonged the survival of SOD1-G93A mice. Mechanistically, OMT treatment enhanced motor neuronal survival and alleviated the activation of microglia and astrocytes compared with those in the vehicle-treated group. Furthermore, the expression of the proinflammatory mediators was downregulated, and the expression of the anti-inflammatory factors was upregulated in the OMT-treated group compared with those in the vehicle-treated group (P < 0.05). Thus, the treatment with OMT had neuroprotective effects, promoting neuronal survival and extending the lifetime of SOD1-G93A mice by suppressing neuroinflammation.