Purpose: To investigate the anti-inflammatory effect of Bufei yishen formula on chronic obstructive pulmonary disease (COPD) and klotho expression in cigarette smoke extract (CSE)-treated BEAS-2B cells. Methods: Cigarette smoke extract (CSE) was diluted in Dulbecco's modified Eagle's medium (DMEM) and used to treat a COPD cell model established using BEAS-2B cells. The CSE-treated cells were transfected with klotho overexpression plasmid, and the COPD cell model was treated with Bufei yishen

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... mula. Dexamethasone was used as positive control. Changes in the expressions of klotho, RIG-I, and NF-ĸB were determined using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, while enzyme linked immunosorbent assay (ELISA) was used to evaluate changes in the expressions of IL-6 and TNF-α. Results: Klotho expression level was reduced in COPD model. Overexpression of klotho inhibited the expressions of IL-6, TNF-α, RIG-I, NF-κB, but bufei yishen formula increased klotho expression level and decreased the expressions of RIG-I, NF-κB, IL-6 and TNF-α. However, after CSE treatment, the anti-inflammatory effect of the formula decreased significantly when klotho expression was knocked down. Conclusion: Bufei yishen formula possesses anti-inflammatory effects which are significantly decreased after klotho knockdown. This suggests that the formula probably acts by upregulating klotho expression, thereby down-regulating the expressions of IL-6 and TNF-α via RIG-I/NF-κB pathway. This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest