内毒素对山羊乳腺组织中与乳腺炎相关的酶和细胞因子的影响

8只泌乳期的健康睢宁白山羊,产后72 h分别用内毒素和灭菌生理盐水经乳头管灌注左右侧乳房.灌注前及灌注后0、1、2、3、4、5、6、7、8、9、24 h观察山羊整体及乳房局部变化.灌注24 h后,处死动物,取乳腺组织,部分用Bou in氏液固定,部分用液氮保存.临床症状及病理切片观察均显示,山羊表现典型的急性乳腺炎症状.检测两侧乳腺组织中部分与乳腺炎症相关因子的含量及其基因表达水平的结果表明:与灌注生理盐水对照相比,灌注内毒素侧乳腺组织中N-乙酰-β-D氨-基葡萄糖苷酶(NAGase)、髓过氧化物酶(MPO)、诱导型一氧化氮合成酶(iNOS)的活性及IL-1β、IL-6的含量极显著升高(P<0.01),TNFα-含量显著升高(P<0.05);相同条件下对2种处理组织样中3种细胞因子mRNA表达水平进行PCR扩增,灌注内毒素侧能检到明显的目的条带,对照侧未见明显的目的条带.

Effect of endotoxin on enzymes and cytokines in mammary tissue of goats relating with mastitis

Eight healthy Suining white goats at early stages of lactation were infused with endotoxin(LPS)(50 μg·kg-1) in the left half of the mammary gland and physiological saline solution was infused in the control contralateral half.At intervals of 0,1,2,3,4,5,6,7,8,9 and 24 hours after infusion,mediators of inflammation were measured and the degree of neutrophil infiltration and clinical variables were recorded.After 24 h,the animals were euthanized and mammary tissue was collected.A section was fixed for histopathologic evaluation and the remaining tissue was stored at-70 ℃.Clinical and histopathologic examination indicated that infusion of LPS induced acute mastitis in left half of the mammary gland. Infusion of LPS significantly increased the activity of N-acetyl-βD-glucosaminidase(NAGase),myeloperoxidase(MPO),nitric oxide synthase(iNOS) and the concentration of tumor necrosis factor-α(TNF-α)(P<0.05),interleukin-1β(IL-1β),and interleukin-6(IL-6)(P<0.01).There was a general increase in the levels of mRNA cytokine expression,too.