Objective:

2

To investigate the therapeutic effects and molecular mechanisms of berberine (BBR) for non-alcoholic fatty liver disease (NAFLD) concomitant with type 2 diabetes mellitus (T2DM).

Methods:

2

In vivo

16 db/db mice were randomly assigned to the model group and the BBR group by a random number table method (

n

=8)

with db/m mice serving as the control group. Mice were given BBR [100 mg/(kg•d)

]

or distilled water via gavage for 4 weeks.

In vitro

5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and compound C were introduced as a AMP-activated protein kinase (AMPK) agonist and an inhibitor

respectively. HepG2 cells were induced with palmitic acid (PA

) and high glucose

and the treatment cells received BBR (5 μmol/L)

AICAR (0.8 mmol/L) or compound C (10 μmol/L) or a combination of BBR and compound C for 24 h additionally. Biochemical assays and pathological staining were performed to assess lipid and glucose metabolism. qPCR and Western blot analysis were used to evaluate the mRNA and protein expressions related to fatty acids (FA) translation [including FA transport proteins (FATP) 2

FATP5

CD36

]

FA synthesis [including stearoyl-CoA desaturase 1 (SCD1)

sterol regulatory element-binding proteins-1c (SREBP-1c)

fatty acid synthase (FASN)

]

and FA β-oxidation [acyl-CoA synthetase long-chain family member 1 (ACSL1)

carnitine palmitoyltransferase (CPT)1A

CPT1B

CPT2

short-chain-acyl-CoA dehydrogenase(SCAD)

medium-chain-acyl-CoA dehydrogenase (MCAD)

long-chain-acyl-CoA dehydrogenase (LCAD)

and very-long-chain-acyl-CoA dehydrogenase (VLCAD)

as well as AMPK/Sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) pathway.

Results:

2

In vivo

compared with the model group

the mice in the BBR group showed lower TG

TC

LDL-C

fasting blood glucose levels and improved insulin sensitivity

as well as reduced lipid accumulation in liver tissues (

P

<

0.05 or

P

<

0.01). In the molecules related to fatty acid metabolism

the mice in the BBR group showed decreased protein expression of FASN and increased expressions of ACSL1 and CPT1A (

P

<

0.05). Additionally

the mRNA expressions of fatp5 and CD36 were decreased

and CPT1A

CPT2

SCAD

LCAD

and VLCAD were increased (

P

<

0.05). AMPK/SIRT1/PGC-1α pathway was activated in the liver of BBR-treated mice (

P

<

0.05 or

P

<

0.01).

In vitro

BBR reduced lipid accumulation in HepG2 cells and activated the AMPK/SIRT1/PGC-1α pathway

and these effects were blocked by compound C (

P

<

0.05 or

P

<

0.01).

Conclusion:

2

Berberine activates AMPK/SIRT1/PGC-1α pathway

thereby improving fatty acid metabolism

and ultimately exerts therapeutic effects on NAFLD accompanied by T2DM.