乳头管灌注脂多糖对兔血清酶活性的影响及病理组织学观察

Effect of LPS Administration Via Teat on Serum Enzyme Activities and Histopathology of Mammary Gland in Rabbits

探讨经乳头管灌注脂多糖(LPS)对兔血清酶活性的影响及乳腺病理组织学变化。12只泌乳兔(产后第7天)经乳头管灌注LPS(150μg/kg体重)建立急性临床型乳房炎模型,在灌注前2 h,灌注后6、12、24、487、2 h以及5 d和7 d分别测定血清中乳酸脱氢酶(LDH)、髓过氧化物酶(MPO)、过氧化物酶(LP)及N-乙酰基-1--βD-氨基葡萄糖苷酶(NAG)活性;同时采集乳腺组织进行病理组织学观察。血清酶检测结果显示,LDH、MPO、LP及NAG活性在灌注后6 h^72 h显著升高(P<0.05)。病理组织学观察结果表明灌注LPS后6 h乳腺组织,腺泡腔中可见中性粒细胞;灌注12 h^24 h时组织损伤加重,乳腺组织结构紊乱,浸润大量中性粒细胞;72 h后乳腺组织开始自我修复,7 d时乳腺组织结构基本恢复正常。LDH活性动态变化与乳腺组织损伤程度密切相关。研究结果提示LDH可用于监测乳腺健康状况及作为乳房炎早期诊断候选指标。

In order to investigate the effect of lipopolysaccharide（LPS） administration on activities of enzymes in rabbits,twelve lactating rabbits（7th day after parturition） were challenged by infusing LPS（150 μg/kg body weight） into the fourth mammary gland via the teat duct.At exactly 2 h before inoculation and 6,12,24,48,72 h after infusion LPS,the blood was taken to determine the activities of lactate dehydrogenase（LDH）,myeloperoxidase（MPO）,N-acetyl-β-D-glucosaminase（NAG） and lactoperoxidase（LP） in serum.At the same time,pathological lesions of mammary gland tissue were observed.The results showed that the activity of LDH,MPO,LP and NAG significantly increased within 6-72 h（P0.05） after infusion LPS via teat canal.Histopatholgic examination results revealed that mammary gland had pathological lesions after 6h infusion LPS,but alveolar structures were still discernible,numbers of polymorphonuclears（PMNs） were present in alveoli.The mammary gland had more severe pathological lesion at 24 h after infusion,the normal alveolar structures were lost and infiltrated with numerous PMNs.Mammary gland tissue lesions regenerated after 72 h,returning to normal at 7 d.The LDH activity showed the maximum sensitivity to acute bovine mastitis which induced by LPS.The dynamic change of LDH activity was closely related to the mammary tissue damage.These results indicated that LDH could be as candidate indicator to detect the inflammation degree of mammary gland and earlier diagnosis of mastitis.