Objective      To investigate the effect of cystathionine-β-synthase (CBS) overexpression on amyloid beta peptide (Aβ) metabolism and cognition in amyloid peptide precursor (APP)/presenilin 1 (PS1) transgenic mice.       Methods      CBS overexpression lentivirus was injected into the hippocampus of APP/PS1 transgenic mice

and dummy vector lentivirus was used as negative control. After 4 weeks

cognitive function was measured by Morris water maze. The level of H

2

S was tested by sensitive sulfur electrode assay. The expression and distribution of CBS and Aβ

1-42

were detected by i

mmunohistochemical staining.       Results      H

2

S level in the brain of the mice was significantly increased in the CBS-overexpression group (P0.05). The escape latency was shortened

and the crossing plat times were increased in the CBS overexpression group (P0.05). The level of Aβ

1-42

was decreased (P0.01)

and the number and size of senile plaques were reduced in the CBS-overexpression group (P0.05).       Conclusion      Up-regulation of CBS can reduce the deposition of Aβ

1-42

and improve the cognitive function of APP/PS1 transgenic mice through increasing H2S level in the brain.