Antihypertensive Effect Of Recombinant Genetic Engineering Lactobacillus In Dogs With Renal Hypertension

Objective:In order to observe the effect of renal hypertension model in dogs with a modified method produced two kidney one clip。We want to study the culture of the recombinant genetic engineering lactobacillus with antihypertensive activity Peptides observe and its growth curve。In addition, we also should detect the antihypertensive effect of the recombinant genetic engineering lactobacillus in renal hypertensive dogs and compare its effect with the lactic acid bacteria without being recombined.Method:Three ordinary dogs were choosed, then were randomly divided into 3 groups and marked. We gave A and B groups a two kidneys one clip renal hypertensive model operation, while C group, as a negative control, was not gaven an operation. Then we measured their blood pressure in order to detect the change. The recombinant genetic engineering lactobacillus which can express the foreign gene of ACE inhibitory peptides and lactic acid bacteria with the empty vector, were all from Jilin Agricultural University as a gift. We used MRS medium to train them and promot the recombinant genetic engineering lactobacillus in expression of the ACE inhibitory peptide gene, then we measured the growth curve, carried on the colony counting and counted the effective dosage in dogs according to their body surface area. We fed the dogs of A and C groups with the recombinant genetic engineering lactobacillus, respectively fed the dogs of B group with the empty vector lactobacillus. Wth monitoring of the blood pressure of Dogs daily, we can make a comparison of the change in blood pressure in dogs between before and after the administration of medication and we can also observe the differences of changes in blood pressure of each group by comparison after the administration.Result:The third week after the renal hypertension model surgery, the blood pressure of A and B groups began to increase. Five weeks later, the blood pressure largely reached the hypertensive state. Compared with the preoperative, A group's systolic blood pressure was 59mmHg±5mmHg higher, and the diastolic blood pressure was 33mmHg±3mmHg. Correspondingly the systolic blood pressure of B group was 63mmHg±5mmHg higher than before, and the diastolic blood pressure 42mmHg±3mmHg higher. The blood pressure of A and B groups relatively elevates the 46% and 47%,while as a sham, the blood pressure of the C group has no significant difference with before. After 5 weeks, the systolic blood pressure of the operation groups remained at 180-190mmHg, and stable.Feeding the dogs of A, C and B groups respectively with the recombinant genetic engineering lactobacillus and the empty vector lactobacillus for 3 days, the A and B two groups'dogs'blood pressure began to drop, but the decline rate was small.The systolic pressure droped about 10mmHg, and the diastolic pressure droped about 6mmHg. So there has non-statistics significance (P>0.05). Compared with B group,the rate of decline of A group's blood pressure has no remarkable difference (P >0.05), but the dog's blood pressure of C group did not have the change (P>0.05). We continued to feed the dogs clothing one week according to this dosage, but their blood pressure cannot continue to drop. Further we multiplied the dose to 2 times, and continued to feed clothing one week, but each group of dogs'blood pressure was stable, not having obviously changes.Discussion:In this study, self-made wire (diameter 1.2mm) for canine model of renal hypertension, elevated the blood pressure above 46% after 5 weeks, and the blood pressure was more stable. More successful model shows that this improved method of two kidneys one clip renal canine model of renal hypertension is feasible and has good results.Feeding renal hypertension dogs with the recombinant genetic engineering lactobacillus which can express the antihypertensive activity Peptides for 20 days, there has no significant blood pressure decrease (P>0.05).We Analysis that such results may be have three reasons:(1) Canine stomach and intestines have anatomical and physiological properties, such as gastrointestinal fluid pH, gastric emptying time, which have large differences with human and mouse. In addition, Canine stomach and intestines have the shorter intestinal transit time and larger gastrointestinal mechanical stirring intensity and destructive power, which are not conducive to the adhesion and colonization of Lactobacillus. (2)The expression of foreign genes carried by recombinant genetic engineering lactobacillus will be affected by many conditions, so whether it can express ACE inhibitory peptides and how much it can express need to take in further detection of ACE inhibitory peptides. (3) Because there is only one dog in each group, which is very few samples, although the results were negative, but it can not explain that the recombinant genetic engineering lactobacillus has not the effect of lowering blood pressure in dogs with renal hypertension. So we need to expand the number of samples to validate it's effect in lowering blood pressure.Conclusion:According to the results the following conclusions can be drawn:(1) It shows that this improved method of two kidneys one clip canine model of renal hypertension with self-made wire (diameter 1.2mm) is feasible and has good results, with which we can obtain accessible and stable model of renal hypertension. (2) Lactobacillus is cultivated with MRS medium at 37℃for 20 hours, and when OD value reach 1.8, which is the optimum harvest period for the fermentation. (3) Because there is very few samples, we did not find that the recombinant genetic engineering lactobacillus has the effect of lowering blood pressure in dogs with renal hypertension, and we did not find that it's effect in lowering blood pressure has significant differences compared with ordinary lactic acid bacteria. So we need to expand the number of samples to validate it's effect in lowering blood pressure.