Bifenthrin causes neurite retraction in the absence of cell death: a model for pesticide associated neurodegeneration.
BACKGROUND
Bifenthrin is a synthetic pyrethroid insecticide derivative of naturally occurring pyrethrins from chrysanthemum flowers. Bifenthrin is considered relatively safe and therefore incorporated as the active ingredient in preparations sold over the counter for household use. Recent studies have raised concern that chronic exposure to pesticides in the home setting may increase the risk for neurodegenerative diseases. To address this concer, in the present study, bifenthrin is added to pre-differentiated PC12 and effect of bifenthrin on the retraction of existing neurites is observed a model for neurodegeneration.


METHODS
PC12 cells were differentiated with nerve growth factor for twenty-four hours and then treated with what was determined to be a sublethal dose of bifenthrin for up to an additional 48 hours. The percent of cells with neurites was assessed at various times before and after nerve growth factor treatment. Bifenthrin toxicity was determined using trypan blue exclusion.


RESULTS
Bifenthrin was not toxic to PC12 cells at concentrations ranging from 1 x 10(-10) M to 1 x 10(-4) M. Twenty-four hours after nerve growth factor treatment, a maximum percent of cells had formed neurites and with a treatment of 1 x 10(-5) M bifenthrin, approximately 80% of these neurites retracted in within 12 additional hours and almost all neurites had retracted within 48 hours. Trypan exclusion showed that these cells were viable.


CONCLUSIONS
These data show that bifenthrin can stimulate the retraction of neurites in the absence of frank toxicity.
Nandi
Avishek
A
Department of Biology aand Environmental Studies Program, Adelphi University, One South Avenue, Garden City, NY 11530, USA.
Chandil
Daljit
D
Lechesal
Rethabile
R
Pryor
Stephen C
SC
McLaughlin
Ashlea
A
Bonventre
Josephine A
JA
Flynnx
Katherine
K
Weeks
Benjamin S
BS
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D001556:Hexachlorocyclohexane / Q000633:toxicity; D007306:Insecticides / Q000633:toxicity*; D008959:Models, Neurological; D009410:Nerve Degeneration / Q000139:chemically induced* / Q000473:pathology*; D020932:Nerve Growth Factor / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D016716:PC12 Cells; D011722:Pyrethrins / Q000633:toxicity*; D051381:Rats
D007306:Insecticides; D011722:Pyrethrins; D001556:Hexachlorocyclohexane; C099952:bifenthrin; D020932:Nerve Growth Factor