干酪乳杆菌LC2W菌体的抗高血压作用

为探索干酪乳杆菌LC2W抗高血压作用的活性成分,收集了采用MRS液体培养基培养的干酪乳杆菌LC2W菌体,洗涤后重悬到10%(w/w)无菌脱脂乳中,至终浓度为1010CFU/mL。将菌悬液分成两组,一组直接进行冷冻干燥(活菌组);另一组在100℃水浴10 min后再进行冷冻干燥(灭活组)。按2.0×109CFU/Kg的剂量(活菌组)或相当浓度的灭活菌体对鼠龄17~18周的自发性高血压大鼠单次或连续灌胃15日,每日一次,对照组给予同样体积的脱脂乳。采用尾环法测定大鼠的收缩压和心率。连续灌胃试验中,于灌胃后4 h测定大鼠的收缩压(Systolic blood Pressure,SBP)和心律(Heart rate,HR)。采用称重法测定大鼠第1 d和第15 d时的体重。结果表明,灌喂LC2W菌体可以显著降低SHR的收缩压,这种作用在灌胃后4 h最显著(P<0.01);在连续灌胃试验中,无论是活菌组还是灭活组在第1、4、8、11和15 d都有显著的抗高血压作用(P<0.01)。未观察到LC2W菌体对实验动物心律和体重有明显的影响。上述结果表明在干酪乳杆菌菌体中存在热稳定性、具有抗高血压作用的物质。

Antihypertensive Activity of Single Cell Protein of Lactobacillus casei LC2W

The single cell protein of Lactobacillus casei LC2W was collected from the MRS broth and suspended in sterile reconstituted skim milk(RSM) to a concentration of 1010 CFU/mL after washing with 100 mM phosphate buffered saline solution(pH 7.0,PBS).The cell suspension was lyophilized directly(viable) or treated in boiling water for 10 min and then lyophilized(heat-killed).The spontaneously hypertensive rats(SHR) were treated with lyophilized LC2W cells(viable or heat-killed) at a dosage of 2.0×109 CFU/Kg per day for a single oral administration or consecutively for 15 d,while the control group was administrated with equivalent volume of RSM.The systolic blood pressure(SBP) and heart rate(HR) of rats were measured by tail-cuff method at 4 h after treating of the 1d,4 d,8 d,11 d,and 15 d in the case of consecutive administrations,whereas the body weights were measured at 1 d and 15 d,respectively.The results showed that the SBP of SHR was decreased significantly from 2 h to 4 h after treating LC2W viable cells or heat-killed cells in single oral administration test.Meanwhile,when SHR were administrated with LC2W cells for consecutive 15 d,both the viable cells and heat-killed cells exhibited significant antihypertensive activities(P<0.01).However,no significant difference on heart rate or body weight was observed between the test groups and the control.It suggested that there are heat stable components on the LC2W cells surface,which might be effective in decreasing the blood pressure of SHR.