Yang Guangcheng, Liang Chen, Yuan Rongxian, Zhou Xunrong, Dai Xin
Objective To investigate the effects and mechanisms of processed Polygonatum derived from a novel combined processing technology with Rehmannia glutinosa on learning and memory functions in D-galactose-induced aging rats. Methods SD male rats were randomly divided into five groups (n=12 per group): blank control, model, Ginkgo biloba tablet (0.01 g/kg), novel-processed Polygonatum (1.95 g/kg), and traditionally-processed Polygonatum (1.95 g/kg). Except for the blank control group receiving subcutaneous normal saline, all other groups received subcutaneous injections of D-galactose (200 mg/kg) for 8 consecutive weeks to establish aging models. Starting from the 5th week of modeling, rats were administered corresponding drugs or normal saline by gavage for 4 consecutive weeks. On days 26 and 28 of administration, Morris water maze tests were conducted to evaluate escape latency and spatial probe trials. Following the experiment, serum was collected to determine malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels. Brain tissues were harvested, fixed, sectioned, and stained with hematoxylin-eosin (H&E) to observe pathological changes in the cerebral cortex and hippocampal CA1 region,so as to compare the anti-aging effects and effects on learning and memory impairment between the old polygonatum group and the new polygonatum group. Results Compared with the blank control group, rats in the model group exhibited typical aging characteristics including sparse hair, slow movement, and lethargy; body weight was significantly lower from the 2nd week onward (P<0.01); escape latency was prolonged and platform crossing frequency decreased (P<0.01); serum MDA increased while SOD and GSH-Px activities decreased (P<0.01); cortical and hippocampal neurons displayed disordered arrangement with nuclear pyknosis and blurred cellular structures. Compared with the model group, all drug-treated groups showed significant improvements: body weight recovered from the 6th week (P<0.05 or P<0.01); escape latency shortened and platform crossings increased (P<0.01); MDA decreased while SOD and GSH-Px increased (P<0.01); neuronal structural integrity improved with alleviated cellular damage. Between the two processed Polygonatum groups, except that escape latency in the novel-processed group was significantly shorter than that in the traditionally-processed group (P<0.05), no significant differences were observed in other indices. Conclusion This novel combined processing technology for Rehmannia glutinosa and Polygonatum retains antioxidant and anti-aging efficacy comparable to traditional processing methods.Meanwhile, it substantially reduces processing time and resource consumption, demonstrating excellent application potential.