| Bovine mastitis is one of the most harmful diseases in dairy productions. Recently, It detected that when researching the pathologic mechanism and clinical symptoms of bovine bacterial mastitis. The research by applying animal models is an important trick to work on mastitis. The methods not only offer important clews for the nosogenesis and development of mastitis, then in result of fomenting the alteration of animal tissues, but also offer effective information for the exploition of neotype antibacterials through trial and error with animal. With the purpose of searching for the more classic, low-cost, and easily established animal mastitis model, and simultaneously in order to supply scientific accordance of studying the pathologic mechanism, diagnose, pharmacotherapy effectives and prognosis of mastitis, the following sequentiase researches were carried out.Research 1. Establishment of experimental mastitis model by infusing Staphylococcus Aureus and Escherichia coli via teat duct in rabbit.48 healthy rabbits of parturition 7d were divided into control group (T1), Staphylococcus Aureus group (T2) and Escherichia coli group (T3) randomly,16 rabbits per group. Staphylococcus Aureus and Escherichia coli,1.5×105 CFU, were infused into glands of rabbit. The ear venous blood and breast tissue were collected at 2h before, and 6h,12h,24h,48h,72h,5d,7d after infusion with asepsis broth and bacterial respectively. Breast textures of rabbit were observed at different time point. Body temperature and WBC, LYM, GRA, contents of CRP, TNF-αof serum and TNF-αof breast tissue, and the variations of dynamic pathology of gland tissue through making pathological section were observed. The result showed that (1) Body temperature of rabbit showed up step-up tendency, and WBC, LYM, GRA also present variety correspondingly, this make clear that engine block had determinate inflammatory reaction. (2) The concentration of TNF-αin serum submit downturn in T2 and T3, in tissue, TNF-αincreased significantly(P<0.05), the concentration of CRP in serum increased correspondingly. (3) Rabbits appeared with clinical symptoms of acute mastitis after infusing bacterial via teat candal. Breast tissue also showed up athological change correspondingly. So it was indicated that experimental mastitis model had been successfully established.Research 2. Effects of infusing Staphylococcus Aureus and Escherichia coli via teat duct in rabbit on activities of SOD, GSH-PX, NOS, contents of NO in serum.The method of dividing groups of rabbits, infusing bacterial via teat and collecting blood were same as research 1. The activities of SOD, GSH-PX and NOS, content of NO in serum were determined at different time point. Then analyzed the variability within index from different bacterial. The results showed that (1) The activities of SOD and GSH-PX in serum significantly increased in T2 (P<0.05), SOD descent and GSH-PX increased significantly in T3(P<0.05). The change of group T1 was not significant(P>0.05). It makes clear that inflammation is different when rabbits infected mastitis caused by Staphylococcus Aureus and Escherichia coli because of the different contents of ROS. (2) The concentration of NO and activities of iNOS decreased significantly(P<0.05), activities of TNOS increased significantly(P<0.05) in T2. In T3, the concentration of No decreased significantly at 72h(P< 0.05). The activities of iNOS decreased significantly at 12h(P<0.05) and TNOS increased slightly. In T1, the concentration of NO and activities of TNOS increased significantly(P<0.05), iNOS increased significantly at 48h(P<0.05). It makes clear that engine block catalysis NO synthesis of NOS is different. The damage to engine block is different when rabbits infected mastitis caused by Staphylococcus Aureus and Escherichia coli.Research 3. Effects of infusing Staphylococcus Aureus and Escherichia coli via teat duct in rabbit on contents of SAA, HP, S100A12 in serum and tissue.The method of dividing groups of rabbits, infusing bacterial via teat and collecting blood were same as research 1. The contents of SAA, HP, S100A12 in serum and tissue were determined at different time point, then analyzed the variability within index from different bacterial. The results showed that (1) The concentration of SAA increased significantly in serum and tissue in T2(P<0.05). In T3, SAA increased significantly in serum and descent significantly in tissue(P< 0.05). In T1 SAA increased slightly in serum, the change was not significant(P>0.05). This make clear that SAA is sensitive fairly in inflammation. As long as inflammation occurrence, the concentration of SAA increase. (2)The concentration of HP in serum was not significant and increased in tissue in T2. HP decreased significantly in serum in T3(P< 0.05), increased significantly at 7d(P<0.05), the change was not significant in tissue. T1 was not obvious. This make clear that organism released multiplicity of Hb, Hb bind with HP result that the content of HP descent. (3)After 48h of infusion bacterial the content of S100A12 increased significantly in serum in T2(P<0.05), increased significantly at 12h in tissue(P<0.05). In T3, the change high or low of S100A12 showed alternately in serum, increased significantly in tissue at 48h(P<0.05).T1 increased significantly in serum (P<0.05)and not obviously in tissue. This make clear that the change showed up in serum and tissue when inflammation. T2 and T3 was different significantly(P<0.05). Account that, mastitis infect from Staphylococcus Aureus and Escherichia coli are different. |
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