Correlation Analysis Between BDNF and Postoperative Cognitive Dysfunction in Aged Rats

Abstract

Objective: To investigate the relationship between BDNF and postoperative cognitive dysfunction among aged rats. Methods: 36 SPF healthy aged male SD rats were randomly assigned to a control group and a model group, respectively, with 18 rats in each group. Abdominal exploration was performed on the rats in the model group after anesthesia, while the rats in the control group were not operated on after anesthesia. The escape latency and swimming distance of the two groups were analyzed on a day prior to surgery as well as on the first day, third day, and seventh day following surgery; the expression levels of BDNF protein in the hippocampus of rats in the two groups were compared on the first day, third day, and seventh day following surgery; the correlation between BDNF and escape latency and swimming distance was analyzed. Results: The escape latency and swimming distance of the rats in the control group on a day prior to surgery, the first day, third day, and seventh day following surgery did not differ significantly (p > 0.05), but those in the model group had significant behavioral difference (p < 0.05). On a day prior to surgery, the rats in both groups showed no significant behavioral difference in escape latency and swimming distance (p > 0.05), but on the first day, third day, and seventh day following surgery, the escape latency and swimming distance of the rats in the model group were significantly longer than those in the control group (p < 0.05). In the control group, there was no significant difference in the protein expression of BDNF in the hippocampus of rats on the first day, third day, and seventh day following surgery, but there was significant difference in the model group. On the first day, third day, and seventh day following surgery, the BDNF protein expression level in the rats’ hippocampus of the control group was significantly higher than that of the model group (p < 0.05). The data from Pearson correlation analysis confirmed that BDNF protein expression is negatively correlated with escape latency (r = -0.567, p < 0.001) and swimming distance (r = -0.623, p < 0.001). Conclusion: In aged rats, the BDNF protein expression level decreases, and the degree of cognitive dysfunction increases after surgery.