Objective  To investigate the therapeutic effect of Houttuynia cordata extract on endotoxin induced uveitis (EIU) in rats and analyze its anti-inflammatory molecular mechanism.

Methods  In the animal experiment, Lewis rats were randomly divided into 5 groups: normal control group, EIU model group, EIU model+normal saline group, EIU model+Houttuynia cordata extract group and EIU model+dexamethasone group. At 24 hours after modeling, ocular inflammation in five groups of rats was observed and scored, the concentrations of infiltrating cells and proteins in aqueous humor were detected, and HE staining was performed to observe the histopathological changes of ocular tissues. In the cell experiment, rat retinal cells were cultured, and the cells were randomly divided into 4 groups: the normal control group, the LPS group, the LPS+ normal saline group, and the LPS+Houttuynia cordata group. After 24 hours, the survival ability of the four groups of cells, TNF-α, IL-6, and the protein expression levels of inflammation-related pathways were detected.

Results  Compared with the EIU model group, the clinical inflammation score, the number of infiltrating cells, pathological grade and the protein concentration in the EIU model+Houttuynia cordata extract group were significantly decreased (P<0.05). Compared with the LPS group and LPS+normal saline group, the survival rate of retinal cells in the LPS+ Houttuynia cordata group of rats was significantly increased. However, the expression levels of TNF-α, IL-6 mRNA and protein, as well as the protein expression levels of factors related to the PI3K/AKT/mTOR, Wnt/β-catenin, NF-κB/MAPK signaling pathways were significantly decreased (P<0.05).

Conclusion  Houttuynia cordata extract can effectively treat EIU rats and alleviate LPS induced retinal cell inflammation in rats. Its mechanism may be related to inhibition of the activity of PI3K/AKT/mTOR, Wnt/β- Catenin and NF- κB/MAPK signaling pathways.

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