Effect Of Probiotics On Lipoprotein-associated Phospholipase A2Level In High-fat Diet-fed Rats

Objectives:1. To study and observe the differences in lipid and lipoprotein-associatedphospholipase A2(Lp-PLA2) level in rats after administration of high-fat diet.2. To explore the influence of lactobacillus acidophilus and bifidobacterium breveon body weight, abdominal circumference, Lee’s index, lipid andlipoprotein-associated phospholipase A2level on high-fat diet-fed rats.Methods:40male SPF SD (Sprague Dawley) rats (provided by The Experimental AnimalCenter of Dalian Medical University) of3weeks old50±5g in weight were randomlydivided into two groups: control group (group N) and experimental group. Controlgroup10rats fed with standard diet and experimental group30fed with high-fat diet.4weeks later, experimental group rats were further divided into3groups of10ratseach: group A fed with high-fat diet, group B fed with high-fat diet, administered withlactobacillus acidophilus1ml/100g in stomach, group C fed with high-fat diet andadministered with bifidobacterium breve1ml/100g in stomach. Group A and group Nfed with normal saline in the standard of1ml/100g in stomach. All groups couldaccess diet and drinking water without restriction and weighed weekly. After8weeks of experiment, weight, height and abdominal circumference of rats weredetermined, and Lee’s index of rats was calculated. The blood sample were taken fromthe rats and centrifuged for analysis of lipid level and Lp-PLA2by enzymes linkedimmunosorbent assay (ELISA). Then data was analyzed by SPSS19.0software. Results:1.8weeks later, the average weight of Group N, A, B and C were207.86±11.92g,340.24±13.63g,325.32±11.86g and326.23±12.82g respectively. Abdominalcircumference of Group N, A, B and C were13.75±0.56cm,17.05±0.41cm,14.90±0.53cm and15.16±0.73cm respectively. Lee’s index of Group N, A, B and Cwere2902.00±184.07,4713.10±218.43,4282.60±126.79and4257.80±132.80respectively. The weight, abdominal circumference and Lee’s index of Group Awere higher than group N(P <0.05). Group B and C were lower than group A (P<0.05).But there was no statistically significant difference between group B and C (P>0.05).2. Lipid level: the TC of group N, A, B and C were48.82±5.68mg/dl,67.98±3.96mg/dl,52.85±6.31mg/dl and54.75±5.97mg/dl respectively. The TG of groupN,A,B and C were8.28±1.46mg/dl,28.44±3.98mg/dl,18.93±4.27mg/dl and16.61±4.07mg/dl respectively. The HDL-C of groups N,A,B and C were17.30±1.99mg/dl,11.57±1.47mg/dl,14.47±1.51mg/dl and14.68±1.57mg/dl respectively. TheLDL-C of groups N,A,B and C were12.74±1.23mg/dl,17.54±1.72mg/dl,14.50±1.63mg/dl and14.31±1.70mg/dl respectively. In group A the value of TC, TG,LDL-C`s level were higher than those in group N (P<0.05). The value of TC, TG,LDL-C in group B and C were lower than those in group A (P<0.05). But there was nostatistically significant difference between group B and C (P>0.05).The value ofHDL-C in group A was lower than those in group N (P<0.05), group B and C higherthan those in group A (P<0.05), but there was no statistically significant differencebetween group B and C (P>0.05).3. The level of serum lipoprotein-associated phospholipase A2(Lp-PLA2): thelevels of serum lipoprotein-associated phospholipase A2of group N, A, B and C were8.32±1.51ng/ml,27.56±2.81ng/ml,17.11±1.99ng/ml and17.30±2.07ng/mlrespectively. In group A the level of LP-PLA2was higher than those in group N(P<0.05). The level of serum Lp-PLA2in group B and C were lower than those ingroup A (P<0.05). But there was no statistically significant difference between group Band C (P>0.05). 4. Lp-PLA2was positively correlated with TC,and the correlation coefficient is0.54, P＜0.01. It was positively correlated with LDL-C and the correlation coefficientis0.61, P＜0.01. It was negatively correlated with HDL-C and the correlationcoefficient is-0.59, P＜0.01.But there was no relationship between Lp-PLA2and TG.Conclusion:1. After8weeks of feeding rats on high-fat diet, it lead to higher level of weights,lipids and serum lipoprotein-associated phospholipase A2in all high-fat diet-fedgroups.2. Lipoprotein-associated phospholipase A2was positively correlated with serumlipid.3. Lactobacillus acidophilus and bifidobacterium breve have similar effect ondecelerating the increase in weight and decreasing the level of serum lipid andLp-PLA2of high-fat diet-fed rats.