Transcriptomics Reveals Effect of Pulsatilla Decoction Butanol Extract in Alleviating Vulvovaginal Candidiasis by Inhibiting Neutrophil Chemotaxis and Activation via TLR4 Signaling

Abstract

The Pulsatilla decoction is a well-known herbal remedy used in clinical settings for treating vulvovaginal candidiasis (VVC). However, the specific mechanism that makes it effective is still unclear. Recent studies have shown that in cases of VVC, neutrophils recruited to the vagina, influenced by heparan sulfate (HS), do not successfully engulf Candida albicans (C. albicans). Instead, they release many inflammatory factors that cause damage to the vaginal mucosa. This study aims to understand the molecular mechanism by which the n-butanol extract of Pulsatilla decoction (BEPD) treats VVC through transcriptomics. High-performance liquid chromatography was used to identify the primary active components of BEPD. A VVC mouse model was induced using an estrogen-dependent method and the mice were treated daily with BEPD (20 mg/kg, 40 mg/kg, and 80 mg/kg) for seven days. The vaginal lavage fluid of the mice was analyzed for various experimental indices, including fungal morphology, fungal burden, degree of neutrophil infiltration, and cytokines. Various assessments were then performed on mouse vaginal tissues, including pathological assessment, immunohistochemistry, immunofluorescence, Western blot (WB), quantitative real-time PCR, and transcriptome assays. Our results showed that BEPD reduced vaginal redness and swelling, decreased white discharge, inhibited C. albicans hyphae formation, reduced neutrophil infiltration and fungal burden, and attenuated vaginal tissue damage compared with the VVC model group. The high-dose BEPD group even restored the damaged vaginal tissue to normal levels. The medium- and high-dose groups of BEPD also significantly reduced the levels of IL-1β, IL-6, TNF-α, and LDH. Additionally, transcriptomic results showed that BEPD regulated several chemokine (CXCL1, CXCL3, and CXCL5) and S100 alarmin (S100A8 and S100A9) genes, suggesting that BEPD may treat VVC by affecting chemokine- and alarmin-mediated neutrophil chemotaxis. Finally, we verified that BEPD protects the vaginal mucosa of VVC mice by inhibiting neutrophil recruitment and chemotaxis in an animal model of VVC via the TLR4/MyD88/NF-κB pathway. This study provides further evidence to elucidate the mechanism of BEPD treatment of VVC.