Effect of Milbemycin oxime on Toxocara canis Eggs and Larvae

Toxocara canis （T.canis） is one of the most important zoonotic parasites of dogs.The aim of the present study was to perform an in vitro analysis of the effect of Milbemycin oxime on T.canis eggs following exposure to a concentration gradient of the drug and to determine the inflammatory reaction produced by the infective T.canis larvae in mice.The present study was undertaken using the model nematode,T.canis,to investigate the effect of Milbemycin oxime on T.canis eggs and larvae.T.canis eggs were exposed to a concentration gradient of Milbemycin oxime in vitro,the higher concentration of Milbemycin oxime was,the lower percentage of infective stage larvae was.Light micrographs showed that Milbemycin oxime induced eggs dissolved and eggshell broken.Histological analyses of mice that stained with hematoxylin and eosin （H＆E） showed in lower dosing (10^-7 and 10^-8 g·mL^-1) drug-treated groups,atrophy of alveolar space and interalveolar septum thickening appeared,inflammatory infiltrates accompanied with erythrocytes around blood vessels and bronchioles presented.In higher dosing (10^-6,10^-5 and 10^-4 g·mL^-1) drug-treated groups,low-grade or no pathological changes occurred,indicating that Milbemycin oxime could obviously decrease the inflammatory reaction produced by the infection of T.canis larvae in vivo.