Toxicity test of recombinant lysostaphin to rats

The experiment was conducted to observe the acute toxicity of recombinant lysostaphin(rlysostaphin) and its long-period toxicity to rats.In the acute toxicity experiment,the rats were orally administrated rlysostaphin at a dosage of 5 000 mg/kg,and then the symptoms were observed and 50 percent lethal dose(LD50) was calculated.In the long-period toxicity experiment,the rats were orally administrated rlysostaphin at different dosages of 72,360,180 mg/kg,and the administrations were lasted for 180 d.Body weight,hematological and hematobiochemical parameters,and histopathological changes were measured in rats at 45 d,90 d,135 d and 180 d after oral administration.The results showed that the LD50 of rlysostaphin was over 5 000 mg/kg in rat.No significant toxic effects were found in the rats with a long-term oral administration.The results indicated that rlysostaphin is safe to use in accordance with the prescribed dose.