title: [Effects of aluminium chloride on the methylation of app in hippocampal of rats].
abstract: OBJECTIVE
  To study the effect of aluminum chloride on amyloid precursor protein ( APP ) promoter methylation and the content of amyloid beta-protein (Abeta) in hippocampus of rats.
  
  
  METHODS
  Forty male SPF grade SD rats were divided into four groups: control group (0.9% NaCl), 10 mg/kg AlCl3 group, 20 mg/kg AlCl3 group, and 30 mg/kg AlCl3 group, respectively. After treatment for 8 weeks, the APP methylation level and expressions of APP mRNA was detected by methylation specific PCR and quantitative real time PCR, respectively. The content of APP and Abeta were detected with enzym-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  With the increase of the content of aluminium chloride, the escape latency were significantly prolong (P < 0.05), numbers of traversing flat in AlCl3 20 mg/kg and AlCl3 30 mg/kg group high and were significantly decreased (P < 0.05), the methylation level of APP contaminated by AlCl3 were decreased (chi2 = 27.61, P < 0.05), the level of APP methylation in 30 mg/kg AlCl3 group was lower than three groups (P < 0.01). With the increase of aluminium chloride, the level of APP methylation were decreased (chi2 = 19.08, P < 0.01). With the increase of the content of aluminium chloride, the methylation level of APP treated with 20 mg/kg AlCl3 and 30 mg/kg AlCl3 were decreased compared with control group (P < 0.05), the level of APP methylation in 30 mg/kg AlCl3 group was lower than 10mg/kg AlCl3 group (P < 0.05), the APP mRNA expression level in AlCl3 group was of statistical significance compared to the control group (F = 8.973, P < 0.05), the level of APP mRNA in 30 mg/kg AlCl3 were higher than 10 mg/kg AlCl3 (P < 0.05). Compared with the control group, the content of APP and Abeta in hippocampus of AlCl3 group were increased (F = 11.14, P = 0. 032, F = 17.82, P = 0.018), and 30 mg/kg AlCl3 group were higher than 10 mg/kg AlCl3 (P < 0.05), the content of APP in 20 mg/kg AlCl3 group were higher than 10 mg/kg AlCl3 (P < 0.05). The result of immunohistochemistry revealed that the grey scale in hippocampus, which suggested that the deposition of Abeta was the most in 20 mg/kg AlCl3 group and 30 mg/kg AlCl3 group.
  
  
  CONCLUSIONS
  Aluminium chloride might cause APP promoter methylation decline, affect the APP mRNA and APP expression increased and result in Abeta deposition in hippocampal.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Yang
authors.forename: Yuzhou
authors.initials: Y
authors.lastname: Yuan
authors.forename: Qiao
authors.initials: Q
authors.lastname: Niu
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000494:pharmacology*; D016229:Amyloid beta-Peptides / Q000737:chemistry; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry*; D000818:Animals; D002712:Chlorides / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects*; D008297:Male; D008745:Methylation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D017607:Aluminum Compounds; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D002712:Chlorides; D000077410:Aluminum Chloride