Comparative study on effect of penicillin G, oxytetracyclin and enrofloxacin antibiotics on neutrophil function of the peripheral blood of sheep (in vitro)

The aim of this study was in vitro evaluation of the effects of some common antibiotics in treatment of microbial infections in sheep on in vitro function of neutrophils. Purified neutrophils of sheep incubated with different levels of oxytetracyclin and enrofloxacin (0, 1, 10, 100 and 200 mcg/ml) and penicillin G (0, 250, 500, 1000, 2000 and 4000 IU/ml) antibiotics for one hour in room temperature. Phagocytosis and nitro-blue tetrazolium reduction (NBT) percentage tested in every sample. Mixed model (REML) was used as a statistical procedure. Data means compared by LSMEAN and p<0.01 considered statistically significant. The results showed that LSMEAN of phagocytosis and NBT percentage were not statistically significant in different levels of penicillin G. Phagocytosis and NBT percentage were statistically non-significant comparing to control group up to 10 and 200 mcg/ml (respectively) but, phagocytosis percentage from 100 mcg/ml to upper level and NBT percentage in 400 mcg/ml level were statistically significant (p<0.01). LSMEAN of phagocytosis percentage in 100 mcg/ml (and upper) decreased dramatically for oxytetracyclin (p<0.0001). With the exception of 0 and 1 mcg/ml of oxytetracyclin, other levels of oxytetracyclin decreased NBT percentage (p<0.0001). Then according to the negative effects of those mentioned antibiotics on neutrophil function, we can introduce penicillin G as an antibiotic with minimum inhibitory effects on neutrophil functions (in vitro). But range of non-risk level for oxytetracyclin on neutrophil function was <1 mcg/ml (that may be had not treating effect) then in this view, this drug is not recommended and it shouldn’t be a number one antibiotic.