title: Attenuation of dichlorvos-induced microglial activation and neuronal apoptosis by 4-hydroxy TEMPO.
abstract: The neurotoxic consequences of acute high-level as well as chronic low-level organophosphates exposure are associated with a range of abnormalities in nerve functions. Previously, we have shown that after 24 h of dichlorvos exposure, microglia become activated and secrete pro-inflammatory molecules like nitric oxide, tumour necrosis factor-α and interleukin-1β. Here, we extended our findings and focused on the neuronal damage caused by dichlorvos via microglial activation. For this, neurons and microglia were isolated separately from 1-day-old Wistar rat pups. Microglia were treated with dichlorvos for 24 h and supernatant was collected (dichlorvos-induced conditioned medium, DCM). However, when 4-hydroxy TEMPO (4-HT) pretreatment was given, we observed significant attenuation of dichlorvos-induced microglial activation; we also collected the supernatant of this culture (4-HT + DCM, TDCM). Next, we checked the effects of DCM on neurons and found heavy loss in viability as evident from NF-H immunostaining and MTT results, whereas dichlorvos alone-treated neurons showed comparatively less damage. However, we observed significant increase in neuronal viability when cells were treated with TDCM. Semi-quantitative PCR and western blot results revealed significant increase in p53, Bax and cytochrome c levels along with caspase 3 activation after 24 h of DCM treatment. However, TDCM-treated neurons showed significant decrease in the expression of these pro-apoptotic molecules. Taken together, these findings suggest that 4-HT can significantly attenuate dichlorvos-induced microglial activation and prevent apoptotic neuronal cell death.
authors.affiliation: Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012, India.
authors.forename: Aditya
authors.initials: A
authors.lastname: Sunkaria
authors.forename: Deep Raj
authors.initials: DR
authors.lastname: Sharma
authors.forename: Willayat Yousuf
authors.initials: WY
authors.lastname: Wani
authors.forename: Kiran Dip
authors.initials: KD
authors.lastname: Gill
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D004006:Dichlorvos / Q000037:antagonists & inhibitors / Q000633:toxicity*; D019811:Hydroxylamine / Q000494:pharmacology*; D008297:Male; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D003497:Cyclic N-Oxides; D019811:Hydroxylamine; D004006:Dichlorvos; C505333:TEMPOL-H