Objective:

2

To investigate the mechanism of inflammatory-mediated toll-like receptor 4 (TLR4)-p38 mitogen-activated protein kinase (p38 MAPK) pathway in Kupffer cells (KCs) of non-alcoholic steatohepatitis (NASH) rats and the intervention effect of soothing Gan (Liver) and invigorating Pi (Spleen) recipes on this pathway.

Methods:

2

After 1 week of acclimatization

120 Sprague-Dawley male rats were randomly divided into 8 groups using a random number table (

n

=15 per group): normal group

model group

low-dose Chaihu Shugan Powder (柴胡疏肝散

CHSG) group (3.2 g/kg)

high-dose CHSG group (9.6 g/kg)

low-dose Shenling Baizhu Powder (参苓白术散

SLBZ) group (10 g/kg)

high-dose SLBZ (30 g/kg) group

and low- and highdose integrated recipe (L-IR

H-IR) groups. All rats in the model and treatment groups were fed with a high-fat diet (HFD). The treatments were administrated by gastrogavage once daily and lasted for 26 weeks. The liver tissues were detected with hematoxylin-eosin (HE) and oil red O staining. Levels of liver lipids

serum lipids and transaminases were measured. KCs were isolated from the livers of rats to evaluate the mRNA expressions of TLR4 and p38 MAPK by real-time fluorescence quantitative polymerase chain reaction

and proteins expressions of TLR4

p-p38 MAPK and p38 MAPK by Western blot. Levels of inflammatory cytokines including tumor necrosis factor α (TNF-α)

interleukin (IL)-1 and IL-6 in KCs were measured by enzyme-linked immunosorbent assay.

Results:

2

After 26 weeks of HFD feeding

HE and oil red O staining showed that the NASH model rats successfully reproduced typical pathogenesis and histopathological features. Compared with the normal group

the model group exhibited significant increases in body weight

liver weight

liver index

serum levels of total cholesterol (TC)

triglyceride (TG)

low-density lipoprotein cholesterol

and aspartate aminotransferase as well as TC and TG levels in liver tissues

and significant decrease in serum level of high-density lipoprotein cholesterol (

P

<

0.05 or

P

<

0.01)

while those indices were significantly ameliorated in the H-IR group (

P

<

0.05 or

P

<

0.01). Higher levels of TNF-α

IL-1 and IL-6 in KCs were observed in the model group compared with the normal group (

P

<

0.01). Significant decreases in TNF-α

IL-1 and IL-6 were observed in the H-SLBZ

H-IR and L-IR groups compared with the model group (

P

<

0.05 or

P

<

0.01). The mRNA expressions of TLR4 and p38 MAPK and protein expressions of TLR4

p38 MAPK and p-p38 MAPK in KCs in the model group were significantly higher than the normal group (

P

<

0.01)

while those expression levels in the L-IR and H-IR groups were significantly lower than the model group (

P

<

0.05 or

P

<

0.01).

Conclusions:

2

Inflammation in KCs might play an important role in the pathogenesis of NASH in rats. The data demonstrated the importance of TLR4-p38MAPK signaling pathway in KCs for the anti-inflammatory effect of soothing Gan and invigorating Pi recipes.