Changes of nitric oxide synthase in brain-gut axis in the physiological aging process of SD rats

Objective: To observe changes of neuronal nitric oxide synthase and endothelial nitric oxide synthase levels in the physiological aging process of SD rats and investigate the possible mechanism of functional gastrointestinal disorders (FGID) in old people. Methods: Twenty-four healthy SD rats were divided into four groups at the age of 3 months, 9 months, 18 months and 24 months, with six rats in each group. The content of neuronal and endothelial nitric oxide synthase in brain-gut axis (brain, gastric body, jejunum, ileum, sigmoid and rectum) was measured by ELISA in each group. Results: Level of neuronal and endothelial nitric oxide synthase in brain-gut axis was decreased with aging, and these changes in the adult rats (9 months, 18 months and 24 months old) were more significant (P<0.05, P<0.01). The distribution of neuronal and endothelial nitric oxide synthase in brain-gut axis was uneven, and this non-uniform distribution did not change with aging. Conclusion: The content of neuronal and endothelial nitric oxide synthase in brain-gut axis of SD rats is decreased in the physiological aging process. These changes may participate in the occurrence and development of functional gastrointestinal disorders in old people.