| This study established the animal experimental mastitis model and investigated the changes of mammary immune function and the systematic immune function when experimental mastitis was induced with endotoxin. The effects of astragalus polysaccharide and glutamine on the animal experimental mastitis were studied. This study also induced bovine mastitis with endotoxin and examined the changes of immune factors and the effect of astragalus polysaccharide on them.1. Establishment of Experimental Mastitis Model by Endotoxin via Teat Duct in RatTwenty lactating SD rats were randomly divided into control group (n=5) and treatment group (n=15). Either sterile physiological saline solution (PSS) or different amount (5 μg, 10 μg, 50 μg) endotoxin was inoculated into the fourth mammary gland (abdominal) via the teat duct 72 hours after parturition. Exactly 24 hours after inoculation. the rats were euthanatized and the mammary glands were removed and fixed for histopathologic evaluations. Tumor necrosis factor-a (TNF-a) concentration. N-acetyl-β-D-glucosaminidase (NAGase) activity and secretory IgA (sIgA) concentration in the mammary glands and plasma were determined, respectively. Histopathologic examination of mammary gland revealed that 5 μg endotoxin-infused mammary glands had pathological changes but alveolar structures were still discernible, numbers of polymorphonuclear neutrophils (PMN) were present in alveoli. Cases of the 10 ug endotoxin-infused mammary glands were similar. While the mammary glands infused with 50μg endotoxin had more severe pathologic lesion, the normal alveolar architecture was lost and infiltrated with numerous PMNs. In comparison with those of PSS-treated rats, TNF-α concentration, sIgA concentration and NAGase activity were significantly (P<0.05) higher in 50μg endotoxin-infused mammary glands. TNF-α concentration in plasma had no...
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