Therapeutic Effects of Baicalin on Diseases Related to Gut-Brain Axis Dysfunctions

Integrated microbiome and metabolomics revealed the protective effect of baicalin on alveolar bone inflammatory resorption in aging

BACKGROUND

With the growing aging population and longer life expectancy, periodontitis and tooth loss have become major health concerns. The gut microbiota, as a key regulator in bone homeostasis, has gathered immense interest. Baicalin, a flavonoid compound extracted from Scutellaria baicalensis Georgi, has shown antioxidant and anti-inflammatory activities.

PURPOSE

This study investigated, for the first time, the protective mechanism of baicalin against alveolar bone inflammatory resorption in aging mice by regulating intestinal flora and metabolites, as well as intestinal barrier function.

METHODS

A ligature-induced periodontitis model was established in d-galactose (D-gal)-induced aging mice, and baicalin was administered at different dosages for 13 weeks. Body weight was measured weekly. The antioxidant and anti-inflammatory activity of baicalin were evaluated using serum superoxide dismutase (SOD), malonaldehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) levels. The immune capability was assessed by thymus and spleen indices. Histopathological changes were observed in the heart, liver, ileum, and periodontal tissues. Alveolar bone absorption of maxillary second molars was examined, and osteoclasts were counted by tartrate-resistant acid phosphatase (TRAP) staining. Furthermore, fecal samples were analyzed using 16S rRNA sequencing and non-targeted metabolomics to identify differences in intestinal bacterial composition and metabolites.

RESULTS

Baicalin exhibited anti-aging properties, as evidenced by increased SOD activity and decreased levels of MDA, IL-6, and TNF-α in serum compared to the control group. Baicalin also ameliorated alveolar bone loss in the d-gal-induced aging-periodontitis group (p < 0.05). Furthermore, baicalin restored ileal permeability by up-regulating the expression of ZO-1 and occludin in aging-periodontitis groups (p < 0.05). Alpha diversity analysis indicated that baicalin-treated mice harbored a higher diversity of gut microbe. PCoA and ANOSIM results revealed significant dissimilarity between groups. The Firmicutes/Bacteroidetes (F/B) ratio, which decreased in periodontitis mice, was restored by baicalin treatment. Additionally, medium-dosage baicalin promoted the production of beneficial flavonoids, and enriched short-chain fatty acids (SCFAs)-producing bacteria.

CONCLUSION

Intestinal homeostasis is a potential avenue for treating age-related alveolar bone loss. Baicalin exerts anti-inflammatory, antioxidant, and osteo-protective properties by regulating the gut microbiota and metabolites.

Baicalin enhances proliferation and reduces inflammatory-oxidative stress effect in H2O2-induced granulosa cells apoptosis via USP48 protein regulation

BACKGROUND

Oxidative stress and inflammation can lead to apoptosis of ovarian granulosa cells (GCs), resulting in ovulation disorders and infertility. Baicalin (BAI) promotes cell proliferation and reduces inflammation and oxidative stress. However, the mechanisms by which BAI treatment affects oxidative stress and inflammation in GCs remain incompletely understood.

METHODS

KGN cells were treated with hydrogen peroxide (H2O2) to analyze the effect of oxidative stress on GCs in vitro. Subsequently, H2O2-stimulated KGN cells were treated with BAI. The levels of GSH-Px, CAT, and SOD were measured using an activity assay kit. The levels of MDA, IL-1β, IL-6, IL-8, and TNF-α were measured by ELISA. Proliferation, apoptosis, and mRNA and protein levels were measured using the CCK8, flow cytometry, qRT-PCR, and western blotting.

RESULTS

H2O2 treatment inhibited KGN cell proliferation and promoted apoptosis, accompanied by increased oxidative stress and inflammation. BAI promoted proliferation, inhibited apoptosis, and reduced oxidative stress and inflammation in H2O2-stimulated KGN cells. BAI treatment promoted USP48 protein expression, and USP48 knockdown abrogated the protective effects of BAI, indicating that USP48 is a downstream mediator of BAI.

CONCLUSION

BAI treatment enhanced cell proliferation and ameliorated oxidative stress and inflammation by enhancing USP48 protein expression. BAI, which is used clinically and as a dietary supplement, may alleviate oxidative stress-induced GC injury and ovarian disorders.