The protective effect of PK11195 on D-galactose-induced amnestic mild cognitive impairment in rats

This study aimed to investigate the preventive effect of translocator protein 18kDa (TSPO) ligand PK11195 on amnestic mild cognitive impairment (aMCI), as well as its influence on astrocytes, in order to identify effective ways to prevent aMCI.Male SD rats were randomly divided into control group (n=10), aMCI group (n=10), PK11195 group (n=10), PK11195 + D-gal group (n=10). The preventive effect of PK11195 on aMCI in rats was evaluated. The cognitive function of rats in four different treatment groups was determined using the Morris water maze (MWM), as well as whole-brain pathology and immunofluorescence of rat brain tissue.The results of the MWM behavioral test showed that rats pre-treated with PK11195 had improved escape latency and a higher number of platform crossings compared with the aMCI model rats. PK11195 was also shown to prevent the D-galactose (D-gal)-induced senescence of pyramidal cells in the hippocampal CA1 region and to inhibit the apoptosis of astrocytes. At the same time, compared with the aMCI model rats, the TSPO in the brain tissue of rats pretreated with PK11195 had a lower distribution density.Our results prove that PK11195 can effectively prevent D-gal-induced decline of learning and memory function as well as inhibit abnormal changes of related cells.