The Effect Of Protein Shadoo In Aging Mice

Shadoo protein is the third prion protein in proteins family, Shadoo protein screened by Genomics approach is similar to prion protein(PrP). It’s encoding gene is Sprn, the expression of Shadoo protein and prion protein are basically the same, Shadoo protein has the nerve protective effect which is similar to prion protein. Studies have shown that prion protein has neuroprotective and antioxidant effects, and participates in the process of biological aging, Shadoo protein and prion protein have many similarities,isconsidered as a special factor transformation process of normal prion protein PrPC toabnormal prion PrPSc.Shadoo protein deficiency can lower cognition and memory excitability, so we think that Shadoo protein may be a regulatory role on physiological senescence.In this paper,we chose Shadoogene knockout aged rats as a model,and compared with wild type(WT) aged mice to study the brain regulating function of Shadoo protein.Built Sprn knockout mice strain, and screened Sprn knockout double chromosome homozygous mice by PCR,and fed to 18 months age.1.To study the shadoo protein on the impact of learning and memory, we used the Sprn-/- aged mice and wild aged mice to observe the behavior changes of two kinds of mice by passive avoidance shuttle experiments, step down test, water maze and locomotor activity experiments. The results showed that Place navigation experiment in the water maze, on the third day, fourth day and sixth day, the differences were significant(P<0.05), and the remaining days were not significant.In space exploration experiment,the number of Sprn-/- mice went through the virtual platform was less than wild mice,and the time of the first timepassed through the platform was more than 40 s,the search mode of the wild mice had obvious tendency, and the Sprn-/- mice were random.In the locomotor activity experiment,the activity of Sprn-/- mice were less than wild mice,on the second day,third day,fourth day,the differences were significant(P<0.01).In the passive avoidance test, the number of shocks in Sprn-/- mice was more than wild mice and on the first day, the number of shocks in Sprn-/- mice was less than wild mice on the second day and third day,but the differenceswere not obvious(P>0.05);On the Jumping experiment, no significant differences in Sprn-/- mice and wild mice about jumping times, but the number of Sprn-/- mice was less than wild mice,the wild mice demonstrated a stronger ability of learning and memory than the knockout mice;Studies have shown that wild mice learning and memory abilities were stronger than the Sprn-/- mice. All of this reflects that shadoo protein deficiency damagesthe learning and memory abilities.2.Observe and count the density of the hippocampus area neurons and the cerebral cortex neurons of Sprn knockout mice by using Golgi staining. The results showed that the neocortex of Sprnknockout aged mice was thinner than wild type aged rats,the molecular layer of glial cells decreased.The neuron density in hippocampus and cerebral cortex of Sprn knockout micewere less compared with Wild-type mice. HE staining was used to observe the two kinds of rats’ cerebellum, hippocampus, cerebral cortex, small vertebral cells in the cerebral cortex, Sprn knockout aged rats brain cortex vertebral facet cells were significantly less than that the wild-type mice and cerebellar granule layer became thiner,purkinje cell layer of two kinds of rats became chaos.3.To ensure the changes of protein and detect the neurotransmitter related to aging, the gene of neurotransmitter receptor and protein expression by using RT-PCR and Western blot. Western blot results showed that compared with wild type(WT) aged mice, Sprn knockout aged rats GFAP protein expression decreased;RT-PCR results showed that compared with the wild type(WT) aged mice hippocampus, the abundance of Sprn knockout aged ratsGFAP and Ras-GRF1 mRNA decreased.