The Effects Of TRPC1 Depletion On Spatial Memory Of Mice And The Invention Of Environmental Enrichment

Objective: Transient receptor potential channels 1(TRPC1) was widely expressed in central nervous system, but its function in the brain was still unknown. In this study, we aimed at preliminarily exploring the effects of TRPC1 depletion on spatial memory of mice, and the possible invention of EE treatment and the molecular mechanisms.Methods: In this study, we used 3-5 month-old TRPC1-/- mice and WT mice. The WT mice and TRPC1-/- mice were randomly divided into four groups: WT mice, EE-treated WT mice, TRPC1-/- mice and EE-treated TRPC1-/- mice. The WT and TRPC1-/- mice were treated by EE for 6 weeks. Using fear conditioning test, Y maze test and step-down test experiment testing the effects of TRPC1 depletion and EE treatment on spatial memory of mice. Then, we used two-dimensional fluorescence difference gel electrophoresis(2D-DIGE) coupled with mass spectrometry to study the influence of TRPC1 depletion on the potential molecular mechanisms of mice, and the mechanism of the invention treated by EE. Immunofluorescence, Nissal staining and TUNEL staining test neurons loss/apoptosis for each group. Using Western blot to verify the differentially expressed protein screened by proteomics.Results: Significant spatial memory impairment assessed by conditional fearing test, Y maze test and step-down test in TRPC1-/- mice was revealed. The behavioral abnormality could be attenuated by the treatment of environment enrichment. Proteomic analysis by 2D-DIGE revealed that TRPC1 deletion caused differential expression of a total of 10 proteins(8 up-regulated and 2 down-regulated) in hippocampus compared to WT mice. EE treatment caused significantly differential expression of a total of 22 proteins(2 up-regulated and 20 down-regulated) in hippocampus of TRPC1 knockout mice. Among these differentially expressed proteins, the expression of voltage-dependent anion-selective channel protein 2(VDAC 2) was significant increased in TRPC1-/- mice compared to WT mice.The expression of α-internexin and glia maturation factor β(GMF-β), two proteins which has been shown to impair memory, were significantly down-regulated by EE treatment in hippocampus of TRPC1-/- mice. Immunofluorescence, Nissal staining and TUNEL staining showed TRPC1 depletion result in neuronal cells loss/apoptosis. Western blot reaveled the expression level of α-internexin and GMF-β was changed, these data further validated the data by 2D-DIGE.Conclusion: Taken together, our data showed that TRPC1 depletion induced memory impairment and altered the expression of proteins in hippocampus in mice, the mechanism may be neuronal loss caused by TRPC1 depletion. Spatial memory impairment by TRPC1 depletion is ameliorated by environmental enrichment. The functional analysis on the differential expressed protein suggested that α-internexin and GMF-β may be the key molecules involved in EE treatment improved memory impairment in mice.