The Protective Role And Mechanism Of Prolyl Cis-trans Isomerase Pin1 In Age-related Neurodegenerative Damage Induced By Cobalt Chloride In Mice

Objective To study the effects of cobalt chloride on neurodegenerative damage in mice and to explore the role of prolyl cis-trans isomerase?Pin1?in the degeneration of brain cells induced by CoCl₂ and its possible regulatory mechanisms.Whether the molecular mechanism of Pin1 plays a role in the damage of mouse brain neurons induced by cobalt chloride is age-related.Part?Age-related neurodegenerative damage induced by cobalt chloride in miceMethods Forty C57BL/6 male wild type and Pin1 knockout type 2 month old mice and Forty C57BL/6 male wild type and Pin1 knockout type 12 month old mice were randomly divided into saline group and CoCl₂ group.CoCl₂ group?intraperitoneal injection 4.0,8.0,16.0 mg/Kg?,once a day for 30 consecutive days.?1?Using PCR identification of mouse genotypes;?2?Using Morris water maze test?concealed platform and space exploration experiments?to detect whether cobalt chloride exposure changes the spatial learning and memory function of Wild mice and Pin1knockout mice.?3?Using inductively coupled plasma mass spectrometry?ICP-MS?to detect the contents of heavy metal ions such as cobalt in blood,cerebral cortex and hippocampus;?4?Using HE staining and silver staining and nephron staining observe the pathological changes in hippocampus and cerebral cortex of Wild mice and Pin1knockout mice.;?5?Using qRT-PCR and Western Blotting to detect the expression of mRNA and protein of hypoxia-inducible factor HIF-1?and the expression of Caspase-9 in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice.?6?Using In situ nick end labeling?TUNEL?staining to detect apoptosis in hippocampus and cerebral cortex of Pin1 knockout mice.?7?Using qRT-PCR and Western Blotting to detect the mRNA and protein expression levels of Pin1 gene in hippocampus and cerebral cortex of Wild mice.?8?Using qRT-PCR and Western Blotting to detect the expression of mRNA and protein of glycogen synthase kinase3??GSK-3??in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice.?9?Using qRT-PCR and Western blotting to detect the mRNA and protein expression levels of Tau and pT231-tau and cis pT231-tau and trans pT231-tau involved in neurofibrillary tangles in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice.?10?Using qRT-PCR and Western Blotting to detect the mRNA and protein expression levels of?-amyloid precursor APP and?-amyloid A?1-42 associated with senile plaques in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice.Result?1?Compared with the saline group,cobalt chloride exposure can lead to a decrease in learning and memory ability and exercise capacity in mice of 2 months and 12 months of age.Compared with wild-type mice of the same age,Pin1 knockout can further lead to a decrease in spatial learning and memory ability and exercise capacity in mice.?2?After cobalt chloride exposure,Cobalt ions can enter the hippocampus and cerebral cortex and blood of 2-month-old mice,which can cause some metal ions in the blood and cerebral cortex to flocculate.?3?Cobalt chloride can cause nuclear pyknosis in the hippocampus and cerebral cortex of mice,Increased red neurons,decreased nitropes and increased neurofibrillary tangles;Pin1 knockout can further lead to neurodegenerative pathological changes in hippocampus and cerebral cortex of mice compared with wild-type mice of the same age.?4?With the increase of the dose of cobalt chloride,the neuronal hypoxia and apoptosis damage were more significant in Wild mice and Pin1 knockout mice.?5?With the increase of the dose of cobalt chloride,the mRNA and protein expression levels of Pin1 in hippocampus and cerebral cortex of Wild mice increased.?6?With the increase of the dose of cobalt chloride,the mRNA and protein expression levels of GSK3?in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice increased.?7?With the increase of cobalt chloride exposure,the expression of pT231-tau and Tau protein in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice increased,and cis pT231-tau was not obvious change,trans pT231-tau protein decrease.?8?The levels of mRNA and protein expression of APP and A?1-42 in hippocampus and cerebral cortex of Wild mice and Pin1 knockout mice increased.Conclusion?1?Exposed to cobalt chloride can cause degeneration damage of mouse brain cells,which can reduce the Pin1 protein of nerve cells.?2?Low expression of the Pin1 gene can directly produce the pathogenic cis P-Tau and the insoluble polypeptide A?by promoting the transformation of the Tau and APP proteins in the cis-trans conformation.On the other hand,it can promote the expression of GSK3?and promote the hyperphosphorylation and insolubility of tau.The production of polypeptide A?together promotes the occurrence of neuronal degeneration damage caused by cobalt chloride.