Study On Lowering Lipid Effect Of Green Tea And Tea Polyphenols In Canine

As one member of the family,the family status of canine gradually improves.Obesity,hyperlipidemia and cardiovascular have increasingly become prominent,which seriously affect the life quality of canine.Previous studies have shown that green tea powder and tea polyphenols could decrease the level of blood lipids and affect the expression of genes related to lipid metabolism in chicken and pig.There are no reports about whether green tea powder and tea polyphenols can affect the lipid metabolism in canine.Based on the biological function of green tea powder and tea polyphenols,lowing lipids effect and mechanism of green tea powder and tea polyphenols were investigated in the present study.15 local pastoral canines(parity consistent,normal immunity,5 month old and healthy by clinical examination)were chosen and randomly assigned to three groups(male and female randomly)with 5 canines in one group.Three groups are normal group(basal diet),green tea powder group(basal diet+1% green tea powder)and tea polyphenol group(basal diet+0.25% tea polyphenol).Blood samples were collected every week and the trial lasted for 12 weeks.After fasting and water deprivation for 12 h,body weight was recorded and 2 mL blood without anti coagulation were collected from front limb vein.Serum was obtained through centrifuging for measuring lipid metabolic index.Blood with and without anti coagulation were collected for measuring lipid metabolic and blood rheology index on the final day of trial.Two canines were selected randomly in one group and slaughtered by jugular vein bleeding,liver tissues were obtained.Serum lipid indicators were determined by semi automatic biochemical analyzer.The accumulation of fat droplets in liver tissues were observed by transmission electron microscope.The changes of blood rheology index were detected by blood rheological method.The expression levels of lipid metabolism related genes in liver tissues were measured by quantitative real-time PCR(qRT-PCR).Test results were as follows:Compared with the normal group,body weight showed growth trend in green tea powder group and tea polyphenols group from 0 to 2 week.Body weight in green tea powder group and tea polyphenol group were significantly lower than that in normal group(P<0.05)from 3 to 12 week.Serum total cholesterol(TC)levels in green tea powder group and tea polyphenol group decreased slightly from 1 to 3 week and decresed significantly from from 7 to 12 week(P<0.05).Serum triglyceride(TG)levels in green tea powder group and tea polyphenol group decreased from 4 week and decreased significantly(P<0.05)from 7 to 12 week.Serum low density lipoprotein cholesterol(LDL-C)levels were at the appropriate levels in green tea powder group,tea polyphenol group and normal group from 0 to 5 week.Serum LDL-C levels in green tea powder group and tea polyphenol group decreased from 5 week and decreased significantly(P<0.05)from 7 to12 week.Serum high density lipoprotein cholesterol(HDL-C)levels maintained at the same level from 0 to 5 week and increased from 6th week.Serum HDL-C were higher in green tea powder group and tea polyphenol group than that in normal group(P<0.05).The content of serum HDL-C maintained at the same level in the 0-5 weeks in each group and increased from the 6th week.The content of serum HDL-C was higher in green tea powder group and tea polyphenol group than that in normal group(P<0.05)from 6 to 12 th week.Whole blood viscosity were significant lower in green tea powder group and tea polyphenols group than that in normal canines(P<0.05)under the condition of 1 S-1,5 S-1,50 S-1 and 200 S-1 shear rate.Plasma viscosity is lower in green tea powder group and tea polyphenols group than that in normal group,but there was no difference.Whole blood reduced viscosity in high shear,reduced viscosity in low shear,erythrocyte aggregation index,erythrocyte rigidity index were significant lower in green tea powder group and tea polyphenol group than that in normal canines(P<0.05).The erythrocyte deformation index was higher in green tea powder group and tea polyphenols group than that in normal group,but there was no difference.Compared with normal group,the mRNA expression levels of acetyl CoA carboxylaseα(ACCα),fatty acid synthase(FAS),apolipoprotein B-100(ApoB-100)in green tea group significantly decreased(P<0.05)and the mRNA expression of apolipoprotein A-1(ApoA-1),peroxisome proliferators-activated receptor α(PPARα),acyl-CoA oxidase(ACO)in green tea group significantly increased(P<0.05)in canine hepatocytes.The mRNA expression ACCα,FAS,ApoB-100 in tea polyphenols group significantly decreased(P<0.05)and the mRNA expression of ApoA-1,PPARα,ACO in tea polyphenols group significantly increased(P<0.05)in canine hepatocytes.