Objective

2

To investigate the inhibitory effect of Sangsuyin on airway inflammation in asthmatic rats by regulating the Toll-like receptor 4 （TLR4） pathway.

Method

2

Forty-eight SD rats were randomly divided into a normal group （

n

=8） and an experimental group （

n

=40）. Asthma model was induced in the rats of the experimental group which were further divided into the following five groups according to a random number table： a model group， a dexamethasone group （0.005 g·kg

-1

），and low- （2.1 g·kg

-1

）， medium- （4.2 g·kg

-1

）， and high-dose （8.4 g·kg

-1

） Sangsuyin groups. The drugs were all dissolved in normal saline at 0.01 L·kg

-1

. The rats in the model group and the normal group received normal saline （

ig

） at 0.01 L·kg

-1

. The drug treatment was carried out once per day， for a total of 7 days. The grades of allergic reactions were compared among the groups after intervention. The levels of interleukin-1

β

（IL-1

β

），tumor necrosis factor-

α

（TNF-

α

）， and interferon-

γ

（IFN-

γ

） in serum and bronchoalveolar lavage fluid （BALF） were detected by enzyme-linked immunosorbent assay （ELISA）. Hematoxylin-eosin （HE） staining was used to observe the pathological changes of lung tissues，and the inflammatory cell infiltration scores of lung tissues were compared. The mRNA expression of TLR4 and nuclear factor-

κ

B （NF-

κ

B） was detected by quantitative real-time fluorescence-based reverse-transcription polymerase chain reaction （Real-time PCR）. The expression of TLR4，NF-

κ

B， and the level of phosphorylated NF-

κ

B （p-NF-

κ

B） were detected by Western blot.

Result

2

The success rate of modeling was 95.00%. Compared with the normal group， the model group showed a higher grade of allergic reaction and more severe pathological changes of lung tissues，and the groups with drug intervention exhibited relieved conditions. The levels of IL-1

β

and TNF-

α

in the serum and BALF were higher in the model group than in the normal group，and lower in the groups with drug intervention than in the model group （

P

<

0.01）. The level of IFN-

γ

in the serum and BALF was lower in the model group than in the normal group，and higher in the groups with drug intervention than in the model group （

P

<

0.05，

P

<

0.01）. The inflammatory cell infiltration score，mRNA and protein expression of TLR4 and NF-

κ

B，and the mRNA level of p-NF-

κ

B were higher in the model group than in the normal group，and lower in the groups with drug intervention than in the model group （

P

<

0.01）.

Conclusion

2

Sangsuyin could inhibit allergic reactions，lung tissue lesions， and airway inflammation in asthmatic rats. It is speculated that this effect is achieved by inhibiting the TLR4 pathway，down-regulating the mRNA and protein expression of TLR4 and NF-

κ

B，and reducing the level of p-NF-

κ

B.angsuyin can inhibit allergic reaction，lung tissue lesions and airway inflammation in asthmatic rats. It is speculated that this effect is achieved by inhibiting TLR4 pathway，down regulating the mRNA and protein expression of TLR4，NF-

κ

B，and reducing the levels of p-NF-

κ

B.