Study On The Pharmacodynamics And Toxicology Of Tibetan Medicine Compound Yicaojingxiang Extract On Pasteurella Multocida

In the Qinghai-Tibet Plateau,there are many diseases such as bovine hemorrhagic sepsis with Pasteurella multocida?Pm?as the main pathogen,which causes a large number of cattle and sheep died,and the production performance degraded,causing serious harm to the animal husbandry,and the control effect of conventional vaccine and chemical drugs was unsatisfactory.I had collected and sorted Tibetan medicine compound from the grass-roots animal husbandry and veterinary station in Tibet pastoral areas,and carried out the screening study on the efficacy and toxicology of Tibetan medicines against Pasteurella multocida.The research contents were summarized as follows:?1?Study on the antibacterial activity of Tibetan Medicine Compound against Pasteurella multocida in vitroThree Tibetan medicine compounds were selected to prepare extracts.The inhibition zone diameter and the minimum inhibitory concentration?MIC?of the three Tibetan medicine compound to the standard strain were determined by the Oxford plate assay system and tube dilution,and the best Tibetan medicine compound for the in vitro antibacterial activity was selected and determined.The results showed that Tibetan Medicine Compounds I,II and III have antibacterial effect to the standard strains;the MIC were 15.63 mg/mL,3.9 mg/mL,and15.63 mg/mL,respectively.Tibetan medicine compound II has a good antibacterial activity in vitro.?2?Pharmacodynamic study of Tibetan medicine compound on infection of Pasteurella multocida in miceA mouse model of in vivo infection of Pasteurella multocida with a mortality rate of 75%was established,the mortality of three Tibetan medicine compounds in three different doses and before and after infection was determined,and the pharmacodynamic effect was evaluated.The results showed that the mouse model of Pasteurella multocida infection with 75%mortality was successfully established by identification of pathological anatomy,bacterial microscopic examination,VTEK 2 COMPACT;The mortality of the Tibetan medicine compound I prevention group and the treatment group were 58.3%,41.7%,83.3%,66.7%,58.3%,and91.7%,respectively;While the Tibetan medicine compounds II were 50%,41.7%,81.8%,66.7%,50%,75%,respectively;The Tibetan medicine compounds III were 66.7%,66.7%,66.7%,75%,75%,50%,respectively.?3?Acute toxicity test and subacute toxicity test of Tibetan medicine compound Yicaojingxiang extractThe SPF-grade Kunming mice were selected to determine the lethal dose 50%?LD50?of the extract of Yicaojingxiang and evaluate its acute toxicity;The eighty SPF-grade SD rats were randomly divided into low?10000 mg/kg?,medium?20000 mg/kg?,high?40000 mg/kg?dose groups,and the blank control group?40000 mg/kg i.g.ultra-pure water?.The subacute toxicity test was carried out,with 10 males and 10 females in each group for 30 days,then recorded the state of rats each day.After the experiment,the weight,organ coefficients indexes,haematological indexes,blood biochemical indexes and histopathological examination of rats in each group were analyzed.The results showed that,the LD₅₀ of the extract was not detected,while the maximum tolerated test showed that there was no significant difference between the test group and the blank group?P>0.05?;In the subacute toxicity test,the rats in each group had no obvious adverse reactions during the administration,with the good mental state.Compared with the blank control group,there were no significant difference in the indexes in the low dose group?P>0.05?;The difference of body weight,liver organ index and ALT were extremely significant in the high dose group?P<0.01?,while the lymphocytes,red cells,hemoglobin and platelets of rats were significant difference in female?P<0.01?,with the monocytes was significant difference?P<0.05?,and the difference of serum glucose in male rats was extremely significant?P<0.01?;The haematological indexes and blood biochemical indexes in the midium group were basically normal.Pathological examination showed that there were no significant pathological changes in the organs except for slight liver enlargement in the high dose group.?4?Determination of Salidroside in Tibetan medicine compound Yicaojingxiang extractHPLC method was used to determine the content of Salidroside in extract.The results showed that there was a good linear relationship between Salidroside injection volume ranged from 0.03509375 to 0.56150000 mg/mL,and the relative standard deviation was 0.17%to4.35%.The recovery rate was 90.99%,and the content of Salidroside in the extract was 2.7668mg/g.The method has high detection sensitivity,specificity and repeatability,and the results are reliable.In summary,the Tibetan medicine compound Yicaojingxiang extract has good antibacterial activity against Pm in vivo and in vitro.The acute toxicity test LD₅₀ is much higher than 5000 mg/kg.The results of subacute toxicity test show that,the haematological indexes and blood biochemical indicators were basically normal in the low and middle dose groups,with no pathological changes in the pathological tissues.Therefore,the Tibetan medicine compound Yicaojingxiang extract obtained by screening is safe and reliable in clinical application,which provides a theoretical basis for clinical prevention and treatment of Pasteurellosis.