| Objective: To observe the effects of DNLA on fat accumulation in liver of hypercholesterolemia mice induced by high-fat diet,and explore the mechanism of DNLA regulating fat metabolism.Methods: Male C57BL/6 mice were randomly divided into control diet group(n=25)and high-fat diet group(n=47),and fed control diet and high-fat diet for 11 weeks respectively.When the serum content of TC was significantly increased,the hypercholesterolemia model in mice were established.Control diet group mice were randomly divided into control diet group(CD group)and control diet DNLA intervention group(CD-DNLA group,15 mg/kg).Each group consisted of 11 mice,and was fed with control diet.High-fat diet group mice were randomly divided into model control group(HFD group),DNLA low dose group(DNLA-L group,5 mg/kg),DNLA high dose group(DNLA-H group,15 mg/kg)and positive control group(Simvastatin group,20 mg/kg).Each group consisted of 11 mice,and was fed with high-fat diet.The treatments were administered by gavage once a day for 15 weeks.After the administration,the mice were sacrificed to collect serum and liver.RNA-seq technology was used to observe the changes in the profile of transcriptome induced by DNLA.RT-PCR was used to detect gene expressions of Sgpp2,Scd1,Scd2,Pla2g4 b,Pnpla3,Cpt1 b,Etnppl,Pygm,Socs2,Ppp1r3 c and Lpin1.Western blot was used to detect the protein levels of LPIN1 and SCD1.The expressions of PPARα,PPARδ and PPARγ genes were detected by RT-PCR.Finally,the expression of the PPARγ target genes Lpl,Cd36,Ncor1,Ap1s2 and Agps were observed.Results: After 11 weeks of feeding high-fat diet,the hypercholesterolemia model in mice was established successfully,which showed that the content of serum TC was significantly increased(P<0.05).After DNLA treatment for 15 weeks,the HE staining results showed that there were fatty degeneration and the reduced nucleus in the liver of HFD group mice.Compared with HFD group,the liver fatty degeneration was improved obviously in DNLAL and DNLA-H group.The serum TC content of DNLA-H group was lower than that of HFD group(P<0.05).RNA-seq technology,heat map and principal component analysis were used to explore the expression changes of 371 genes related to liver triglyceride metabolism.The results suggested that the gene expression profile in DNLA-H group was significantly different from that in HFD group,and similar to that in CD group.According to the results,11 genes were screened with the significant changes in HFD group and can be significantly changed after DNLA treatment.The genes of Sgpp2,Scd1,Scd2,Pla2g4 b,Pnpla3,Cpt1 b,Etnppl,Pygm,Socs2,Ppp1r3 c and Lpin1 were selected for validation.The verification results indicated that the mRNA expressions of Pla2g4 b,Pygm and Scd1 were reduced in HFD group compared with CD group(P<0.05).Compared with HFD group,the expression of Lpin1 gene in DNLA-H group was significantly lower(P<0.05),while that of Pnpla3,Ppp1r3 c,Scd1 and Socs2 were significantly higher(P<0.05).Compared with CD group,the protein levels of SCD1 and LPIN1 in HFD group were decreased significantly(P<0.05),and the protein level of LIPIN1 in DNLA-H group was also decreased significantly(P<0.05).Compared with HFD group,the level of SCD1 protein was significantly increased(P<0.05).And the gene expression of PPARγ in DNLA-H group was significantly increased(P<0.05).Compared with HFD group,the expressions of Lpl,Cd36,Ncor1,Ap1s2 and Agps in DNLA-H group increased significantly(P<0.05).Conclusion: This study proves that DNLA can reduce the blood lipid level and improve the liver fat accumulation in hypercholesterolemia model mice induced by high fat diet.The mechanism could be related to activating PPARγ in liver,increasing the expression of target gene,and regulating fat metabolism. |
PDF Full Text Request