The Expression Of NMDAR And The DNA Damage Of Nerve System In Offsprings Of Rats After Prenatal Exposured To Combined Cypermethrion And Mythylparathion

Object: To detect the expression of NMDAR1 and the DNA damage of nerve system in offsprings of rats after prenatal exposured to combined Cypermethrion and Mythylparathion.Methods: 47 pregnant rats were devided into four groups randomly, i.e, control group and three combined pesticides treated groups 1/300LD50,1/95LD50 and 1/30LD50 which corresponding to four level of doses: 0, 0.0230+0.8000mg/kg BW, 0.0725+2.5265mg/kg BW and 8.0000+0.2300mg/kg BW. From the 0-day to the 15-day, each day the rats were exposed to the combined pesticides of Mythylparathion and Cyperthrion orally. Take 5 off-springs rats in each group randomly after birth on 7, 14, 21 and 28 day respectively and by using immunohistochemistry(IHC), detect the NMDAR1 protein expression levels in the regions of pallium, diencephalon and hippocampus. Also Single Cell Gel Electrophoresis (SCGE or Comet Assay) and acrodine orange stain were used to analyse the DNA damage of the neuron cells of the 16~th-day pregnant and the 30~th-day off-spring rats after the cells were trypsinized and made into single-cell suspension.Results: In the 7~th-day offspring sample, positive cells mostly focus in the bottom of the pallium and little cells scatter in other regions of the pallium CA1 ~4 regions. In the 14th, 21th and 28th-day samples, the positive NMDAR1 cells distribute abroad in the whole region of pallium and hippocampus, while relatively centralized in the regions of inner and outer sides of coping pallium, pear-like pallium, hippocampus and reticular-region of diencephalon. The positive cells in such regions were stained deeply and clearly. In the regions of outer side of pallium, the protein expression level of NMDAR1 of the 14th and 21th-day samples in high-dose level was lower compared with the low-dose level(P<0.01) and the positive cells decrease with the increase of the doses(β1= -0.377, P<0.01) which indicates that combinedpesticides of Mythylparathion and Cyperthrion may have significant effect on the expression of NMDARl in CAl region and the relation of level-effect may exists. In the control and low-dose level groups, the NMDARl expression of the 7th group was lower thanH*, 21th and 28th-day. In the middle and high-dose level groups, the NMDARl expression of the 7th group was lower than21th and 28th-day . Compared with the control, the protein expression acme in 21th-day in low and middle reduced incoordinately. In the region of CA3, H^-day samples, the positive ceils in the control and high-dose level groups are both lower than the low-dose level group(P<0.01, P<0.05), which shows that low-dose level combined pesticides may up-regulate the protein expression but with the doses increases, the expression may decrease. In other regions there is not statistical significance among the different groups (P>0.05). The NMDARl level in the regions of pallium, hippocampus CAl and CA3 are different in different time points (P<0.05). In control group, the protein level was lowest in and highest in 21th-day and decreased in 28th-day. The expression acme of three groups are all retrusive and the retrusive tendency was consistent with the increase of the doses. In the range of 1/300LD50 to 1/30LD50, the combined pesticides of Mythylparathion and Cyperthrion can induce the neuron cell DNA strain rupture remarkably of the neuron cell in the ^^-day fetal sample(P<0.05,) while the high-dose level group can induce the damage of the 30th-day off-spring sample (P<0.05) and the neuron, DNA damage(arbitrary unit) increased with the rising concentration of the combined pesticides.(corelation analysis:DNA damage of the 16th-day fetal sample r]=0,836,P=0.000; comet cells appearance rate r2=0.849,P=0.000; DNA damage of the 30th-day off-spring sample r3=0.865,P=0.000; comet cells appearance rate r4=0.969,P=0.000).Conclusions: The exposure to high-level combined pesticides of Mythylparathion and Cyperthrion down-regulated the expression of NMDARl in the regions of outer side of pallium, CAl and CA3 of hippocampus while the low-level exposure up-regulated the expression of NMDARl in the regions of CA3 and delayed the acme of the protein expression in the prenatal rats. Also the exposure induced the neuron cell's DNA chain to rupture and the damage displayed an dose-effect relation and may persist for a long time.