Effect of the herbal formulation Shen-Zhi-Ling on an APP/PS1 mouse model of Alzheimer's disease by modulating the biliverdin reductase/heme oxygenase 1 system

Shen-Zhi-Ling (SZL) oral liquid is a traditional Chinese medicine formula that is mainly used for the clinical treatment of mild to moderate Alzheimer's disease (AD). The aim of the present study was to investigate the effects and underlying mechanisms of SZL treatment on AD. APP/PS1 transgenic mice were utilized to evaluate the effect of SZL treatment (0.5 g/20 g/day). Morris water maze and Thioflavin S staining analyses were used to evaluate the cognitive impairment and β-amyloid plaques, respectively, while quantitative polymerase chain reaction and western blot analysis were performed to examine the mRNA and protein expression levels of heme oxygenase 1 (HO-1) and biliverdin reductase (BVR). Furthermore, immunofluorescence staining was used to measure the BVR and HO-1 protein levels in the hippocampus. The findings of the current study demonstrated that SZL treatment was able to ameliorate the impairment of memory and reduce the accumulation of amyloid plaques, and its ameliorating effects may be attributed to the modulation of the HO-1/BVR system in the hippocampus. These results indicate that SZL may be a possible complementary and alternative therapy to delay the development of AD.