title: [Research of λ-cyhalothrin affect synaptic development in hippocampus by interfering with estrogen action].
abstract: OBJECTIVE
  To explore the effects of λ-cyhalothrin on hippocampus by interfering with estrogen.
  
  
  METHODS
  The healthy female ICR mice of postnatal 28 days were random divided into 12 groups, 4 of those were sham-operation include control, λ-cyhalothrin (LCT, 3.0 µg/g), Letrozole (Let, 1.0 µg/g), and LCT (3.0 µg/g)+Let (1.0 µg/g); and the last 8 were ovariectomized include OVX, Estradiol (E2, 10.0 µg/g), LCT, Let, E2+LCT, E2+Let, LCT+Let, E2+LCT+Let. 10 mice in every group received drugs by intraperitoneal injection for 2 days. Then half of every group initiate the ethological test (open field test and Morris water maze) 24 h later. The last half animals were sacrificed to made frozen section for immunofluorescent assay of postsynaptic density protein 95 (PSD95).
  
  
  RESULTS
  In ethological test, campared with Sham, OVX can lengthen incubation period in the first grid and to get on the platform (P < 0.05); campared with OVX, OVX+E2 can increase the total numbers of through grid and shorten the incubation period to get on the platform (P < 0.05); campared with OVX+E2, OVX+E2+LCT can reduce the number of grid and standing, lengthen incubation period to the platform (P < 0.05); campared with Sham, Sham+LCT can lengthen incubation period to the platform of Sham mice (P < 0.05), but campared with OVX, OVX+LCT can shoten incubation period in the first grid and to get on the platform in OVX mice (P < 0.05); campared with Sham+Let, Sham+LCT+Let can lengthen incubation period in the first grid, reduce the the number of grid and standing (P < 0.05). In the Immunohistochemical fluorescence experiment we find that, campared with Sham, OVX can reduce the expression of PSD95 in CA1,CA3 and DG (P < 0.05); however campared with OVX, E2 or LCT can both inhibit the effect of OVX (P < 0.05); campared with Sham, Sham+LCT can reduce the expression of PSD95, the same result when OVX+E2+LCT campared with OVX+E2 (P < 0.05); campared with OVX+E2+Let, OVX+E2+LCT+Let can reduce the expression of PSD95 in CA3 (P < 0.05); campared with OVX+Let, OVX+LCT+Let can increase the expression of PSD95 in DG (P < 0.05).
  
  
  CONCLUSIONS
  When few estrogen exist in the body, LCT can show estrogen-like action to promote hippocampal synaptic development; but when circulating estrogen exist, LCT can inhibit synaptic development by interfering estrogen.
authors.affiliation: Department of Toxicology, School of Public Health, Anhui Medical University, Hefei 230032, China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Toxicology, School of Public Health, Anhui Medical University, Hefei 230032, China; E-mail: wqn@ahmu.edu.com.
authors.forename: Qunan
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Toxicology, School of Public Health, Anhui Medical University, Hefei 230032, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Xia
authors.affiliation: Department of Toxicology, School of Public Health, Anhui Medical University, Hefei 230032, China.
authors.forename: Nian
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Toxicology, School of Public Health, Anhui Medical University, Hefei 230032, China.
authors.forename: Chengwei
authors.initials: C
authors.lastname: Yang
mesh_terms: D000818:Animals; D004958:Estradiol; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006624:Hippocampus / Q000187:drug effects*; D006801:Humans; D000077289:Letrozole; D051379:Mice; D008813:Mice, Inbred ICR; D009570:Nitriles / Q000494:pharmacology*; D010052:Ovariectomy; D011722:Pyrethrins / Q000494:pharmacology*; D011897:Random Allocation; D013569:Synapses / Q000187:drug effects; D014230:Triazoles
chemical_list: D004967:Estrogens; D009570:Nitriles; D011722:Pyrethrins; D014230:Triazoles; D004958:Estradiol; D000077289:Letrozole; C037304:cyhalothrin