Objective:To investigate the effects and mechanisms of subchronic exposure to pyrethrin on the mice nervous system.Methods:Twenty-four male mice were randomly divided into a control group,low-,medium-,and high-dose groups,and were exposed continuously for 28 days.The control group received corn oil.The general condi-tion of the mice was observed,and the body weight and brain organ coefficient were measured.Neurobehavioral tests were conducted after the exposure period.The histopathological changes of the hippocampus in mice were observed by HE and nissl staining.The activities of lactate dehydrogenase(LDH),superoxide dismutase(SOD),catalase(CAT)and the contents of malondialdehyde(MDA),glutathione(GSH),acetylcholine(ACh)and glutamate(Glu)in brain tissue of mice were detected by biochemical kit.The Western blot was employed to measure the expression levels of kelch-like ech-associated protein 1(Keap1),nuclearfactorerythroid2-relatedfactor2(Nrf2),and heme oxygenase 1(HO-1)in brain tissue of mice.Results:Compared with the control group,the body weight of the mice in the high-dose group decreased,the brain organ coefficient increased,and the neurological function test showed that the mice had reduced autonomic activity,delayed nerve reflex,and impaired sensory and motor function.Histopathology showed that the hippocampal neurons in the middle-and high-dose groups presented with pyknosis,vacuolization,and disordered arrangement of the CA3 area.Biochemical analysis indicated that in the brain tissue of mice,the activity of LDH and the content of MDA were increased in the medium-and high-dose groups,while the activity of CAT and the content of GSH were decreased.The content of Glu was increased and the content of ACh was decreased.The activity of SOD was reduced in the low-,medium-,and high-dose groups.Western blot analysis showed that the expression of HO-1 and Nrf2 protein in the brain tissue of mice in the middle-and high-dose groups was down-regulated,while the expression of Keap1 protein in the high-dose group was up-regulated.Conclusion:Pyrethrin may cause damage to the nervous system by affecting the Keap1/Nrf2/HO-1 signaling pathway and neurotransmitter levels.

Objective:To investigate the effects and mechanisms of subchronic exposure to pyrethrin on the mice nervous system.Methods:Twenty-four male mice were randomly divided into a control group,low-,medium-,and high-dose groups,and were exposed continuously for 28 days.The control group received corn oil.The general condi-tion of the mice was observed,and the body weight and brain organ coefficient were measured.Neurobehavioral tests were conducted after the exposure period.The histopathological changes of the hippocampus in mice were observed by HE and nissl staining.The activities of lactate dehydrogenase(LDH),superoxide dismutase(SOD),catalase(CAT)and the contents of malondialdehyde(MDA),glutathione(GSH),acetylcholine(ACh)and glutamate(Glu)in brain tissue of mice were detected by biochemical kit.The Western blot was employed to measure the expression levels of kelch-like ech-associated protein 1(Keap1),nuclearfactorerythroid2-relatedfactor2(Nrf2),and heme oxygenase 1(HO-1)in brain tissue of mice.Results:Compared with the control group,the body weight of the mice in the high-dose group decreased,the brain organ coefficient increased,and the neurological function test showed that the mice had reduced autonomic activity,delayed nerve reflex,and impaired sensory and motor function.Histopathology showed that the hippocampal neurons in the middle-and high-dose groups presented with pyknosis,vacuolization,and disordered arrangement of the CA3 area.Biochemical analysis indicated that in the brain tissue of mice,the activity of LDH and the content of MDA were increased in the medium-and high-dose groups,while the activity of CAT and the content of GSH were decreased.The content of Glu was increased and the content of ACh was decreased.The activity of SOD was reduced in the low-,medium-,and high-dose groups.Western blot analysis showed that the expression of HO-1 and Nrf2 protein in the brain tissue of mice in the middle-and high-dose groups was down-regulated,while the expression of Keap1 protein in the high-dose group was up-regulated.Conclusion:Pyrethrin may cause damage to the nervous system by affecting the Keap1/Nrf2/HO-1 signaling pathway and neurotransmitter levels.