Abstract: Abstract: 【OBJECTIVE】For further study on therapeutic method of Mastitis, it was in the paper that protection of polysaccharide nucleic acid fraction Bacillus Guerin to mammary tissue of goat experimental Mastitis induced by Endotoxin.【METHOD】Six healthy Suining white goats at early stages of lactation were intramammary infused with polysaccharide nucleic acid fraction of Bacillus Calmette Guerin (BCG-PSN) (5mL) in the left quarters and physiological saline (5mL) in the control contralateral quarters. The administration of BCG-PSN was carried out for six consecutive days. On the seventh day, the mammary quarters (both right and left) of the six goats were infused with Escherichia coli endotoxin (LPS) (50μg/bwt). At varying intervals of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 24h before and after infusion inflammation was recorded. After 24h, the animals were slaughtered and mammary tissue was collected from the same position. A section was fixed for histopathological evaluations and the remaining tissue was stored at -70℃.【RESULTS】Clinical and histopathological examinations indicated that infusion of endotoxins induced acute mastitis in both quarters. The results showed that infusion of BCG-PSN significantly reduced activity of N-acetyl-β-D-glucosaminidase (NAGase), Myeloperoxidase (MPO), alkaline phosphatase (AKP), nitric oxide synthase (iNOS) and the concentration of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (P<0.05). There was a general reduction in the levels of mRNA cytokine expression (P<0.05). These findings suggest that BCG-PSN inhibits release of inflammatory factors that cause damage to mammary epithelial cells during mastitis infections in goats.

Key words: Goats, BCG-PSN, endotoxins, Mastitis