Dose-response modeling of reactivating potency of oximes K027 and K203 against a direct acetylcholinesterase inhibitor in rat erythrocytes.
Inhibition of acethylcholinesterase (AChE) as a key molecular event induced by organophosphate (OP) pesticides and nerve agents presents a human health concern. In efficacy testing of experimental oximes, potential antidotes in OP poisoning, reactivation of OP-inhibited AChE is used as specific endpoint. However, according to our best knowledge, so far oximes have not been quantitatively evaluated by comprehensive benchmark dose (BMD) approach, that would improve both identification and quantification of the effect and allow more rigorous comparison of efficacies. Thus, we have examined in vivo dose-response relationship for two promising experimental oximes, K203 and K027, concerning reactivation of erythrocyte AChE inhibited by dichlorvos (DDVP). Groups of Wistar rats were treated with six different doses of oximes (i.m) immediately after DDVP challenge (s.c) and AChE was measured 60 min later. Dose-response modeling was done by PROAST software 65.5 (RIVM, The Nederlands). BMD-covariate method resulted in four-parameter model from both exponential and Hill model families as the best estimate of relationship between AChE activity and oxime dose, with potency parameter being oxime-dependent. Oxime K027 was shown to be 1.929-fold more potent considering that 58% increase in AChE activity was achived with the dose BMD58-K027 = 52 μmol/kg in contrast to BMD58-K203 = 100 μmol/kg.
['Antonijevic|Evica|E|', 'Musilek|Kamil|K|', 'Kuca|Kamil|K|', 'Djukic-Cosic|Danijela|D|', 'Curcic|Marijana|M|', 'Miladinovic|Dejana Cupic|DC|', 'Bulat|Zorica|Z|', 'Antonijevic|Biljana|B|']
D000110:Acetylcholinesterase D000818:Animals D002800:Cholinesterase Inhibitors D002801:Cholinesterase Reactivators D004006:Dichlorvos D004305:Dose-Response Relationship, Drug D004912:Erythrocytes D008297:Male D015394:Molecular Structure D010091:Oximes D011726:Pyridinium Compounds D051381:Rats D017208:Rats, Wistar
Rat erythrocytes Benchmark dose Dichlorvos PROAST K027 vs K203