Protective Effects of Shi-Zhen-An-Shen Decoction on the Cognitive Impairment in MK801-Induced Schizophrenia Model

Cognitive dysfunction is a core feature of schizophrenia that strongly correlates to the patients' difficulties in independent living and occupational functioning. Synaptic dysfunction may result in cognitive and behavioral changes similar to what have been identified in schizophrenia. Shi-Zhen-An-Shen Decoction (SZASD) is the empirical formula of traditional Chinese medicine adopted in treating psychiatric symptoms, especially the cognitive impairment in schizophrenia patients, with proven efficacy in the long term of clinical practice in Beijing Anding Hospital, Capital Medical University. However, the mechanisms of SZASD on the cognitive improvement in schizophrenia is still unclear. Here, we aim to investigate the underlying mechanisms of the impact of SZASD on the cognitive impairment in MK801-induced schizophrenia-like rats.

Six rat groups (n = 12 per group) were subjected to different treatments for 14 days. All the six groups were injected intraperitoneally with a given volume of 0.9% saline and MK801 (0.2 mg/kg) for consecutive 14 days for modelling. And the rats in the SZASD-treated groups and the clozapine-treated group were given SZASD (low, middle, and high doses) or clozapine, respectively, by intragastric administration. Then, we performed behavioral tests after the treatments, and the rats were sacrificed on the 19th day for biological analysis.

Behavioral tests indicated that SZASD mitigated the aberrant motor activity and improved schizophrenia-like rats' spatial reference memory and sensory gating ability. Furthermore, SZASD significantly increased the expressions of PSD95, BDNF, and synapsin I in the hippocampus of MK801-induced schizophrenia-like rats.

Our findings suggest that SZASD may ameliorate cognitive impairment by restoring the levels of synaptic proteins in the hippocampus.