酸马奶源酵母菌抗菌复合物灌胃剂量的筛选

Screening the optimal dose of antibacterial compounds of yeasts from koumiss

为了筛选酸马奶源酵母菌抗菌复合物的最优灌胃剂量,试验采用乙酸乙酯提取法萃取酸马奶源酵母菌抗菌复合物,高效液相色谱法和增强型BCA蛋白检测试剂盒法测定其主要组分。选取昆明系小鼠150只,随机分为15组,每组10只。空白对照组和阴性对照组小鼠灌胃无菌PBS 7 d;阳性对照组小鼠灌胃环丙沙星;抗菌复合物组小鼠灌胃高（500 mg/kg）、中（250 mg/kg）、低（125 mg/kg）剂量的抗菌复合物;除空白对照组外,其他各组于第4天注射大肠杆菌（E.coli）O8菌悬液。观察小鼠患病症状,采集各组小鼠小肠组织,H.E.染色后观察病理切片,并记录各组小鼠存活率。结果表明：在p H值为2.0和8.0条件下获得酸马奶源马克斯克鲁维酵母菌（K.marxianus）和酿酒酵母菌（S.cerevisiae）的4种抗菌复合物K2、K8、S2和S8,主要成分为有机酸和毒素蛋白。阴性对照组小鼠感染E.coli O824 h后出现明显患病症状;36~72 h期间小鼠患病症状更加严重,死亡小鼠增多。注菌72 h后阴性对照组小鼠小肠组织损害严重;阳性对照组和K2低剂量组小鼠小肠组织较完整;K2高剂量和中剂量组小鼠小肠组织形态有所好转,但仍有少量上皮细胞脱落。K2、S2、S8低剂量和K8中剂量组小鼠存活率较高。说明低剂量125 mg/kg为酸马奶源酵母菌抗菌复合物的最优灌胃剂量。

The aim of the present study was to screen the optimal oral dose of antibacterial compounds of yeasts from koumiss. Antibacterial compounds of the yeasts from koumiss were extracted by ethyl acetate. Then their main components of the extract were determined by using high performance liquid chromatography（ HPLC） and enhanced BCA protein detection kit. Kunming strain mice（ 150 heads） were randomly divided into 15 groups,and 10 mice in each group.The mice in the control group and the negative control group were oral administrated sterile PBS by gavage for 7 d. The mice in the positive control group were oral administrated Ciprofloxacin by gavage. The mice in the high,middle,low dose groups of antibacterial compounds were oral administrated 500,250,125 mg/kg antibacterial compound by gavage. Except for the control group,other groups were all administered intraperitoneally E. coli O8 at the 4 th day. The symptoms and pathological section of small intestine were observed by hematoxylin and eosin（ H.E.） staining,and the survival rates of the mice in each group were recorded. The results showed that four antibacterial compounds of K. marxianus（ K2,p H = 2. 0; K8,p H = 8. 0） and S. cerevisiae（ S2,p H = 2. 0; S8,p H = 8. 0） were obtained.Their main components were organic ac ids and killer toxins. In the negative control group,the mice infected with E. coli O8 for 24 h showed obvious clinical symptoms.During 36-72 h,the symptoms of the mice became more serious and the number of dead mice increased.After injection with E. coli O8 for 72 h,the small intestine in the mice of negative control group were injured seriously,the small intestine in the mice of positive control group and the low dose of K2 group were less intact,the small intestine in the mice of high and middle dose of K2 groups were improved,but some epithelial cells were still shed. Besides,the survival rates of the low dose of K2,S2,S8 groups and the middle dose of K8 group were higher than that of other groups. The results indicated that 125 mg/kg was the best dose fororal administration of the antibacterial compound of yeast derived from koumiss.