Abstract
Shenkang suppository (SKS), a Chinese medicinal preparation rich in various natural ingredients, has not been reported in any studies related to fibrosis. Our experiments validated the anti-fibrotic and anti-inflammatory effects of Rhein (Rh), which is a major component of SKS, and explored its potential immune mechanisms. Tissue and serum specimens from chronic kidney disease (CKD) patients and normal subjects were collected in 30 cases each, and the expression differences of perforin and IFN-γ were analyzed by ELISA. Further, the CKD mice model constructed with folic acid (FA) was used to validate these differences by WB and qRT-PCR to explore the potential nephroprotective mechanism of Rh. Besides, in vitro experiments were conducted to identify the release sources of perforin and IFN-γ. ELISA showed that perforin and IFN-γ were upregulated in CKD patients, and this phenomenon was also corroborated in CKD mice. WB and qRT-PCR data showed that Rh reversed perforin and IFN-γ upregulation, inflammatory factor recruitment, and extracellular matrix (ECM) protein upregulation. Results from in vitro experiments demonstrate that the upregulation of perforin and IFN-γ originates from the stress response of CD4+ T lymphocytes (CD4+ cells), CD8+ T lymphocytes (CD8+ cells) and natural killer cells (NK cells), which can be suppressed by Rh. More importantly, the activated STING/TBK1/IRF3 pathway in CKD was also inhibited by Rh. Our data suggest that Rh possesses anti-fibrotic and nephroprotective effects, which mechanistically are associated with decreased release of perforin and IFN-γ from immune cells, which may be achieved by suppressing the STING/TBK1/IRF3 pathway.