Epigallocatechin‐3‐O‐gallate modulates the diversity of gut microbiota in ovariectomized rats

Epigallocatechin-3-O-gallate (EGCG) exists as one of the major active components of green tea and has been studied extensively; however, the relationship between EGCG and the changes in the gut microflora of ovariectomized (OVX) rats as a model of menopause women have not yet been studied. Female Wistar rats were fed on a maintenance material diet and underwent either ovariectomy or SHAM surgery. The ovariectomized rats were divided into OVX group with the treatment of placebo or EGCG group which was treated with EGCG by oral gavage. After 8 weeks of treatment, anxiety-like behaviors were assessed using elevated plus maze test (EMP) and open field test (OFT). The serum estradiol concentration was assayed through ELISA. High-throughput V3-V4 16S rDNA sequencing was conducted to assess the microbial diversity in fecal samples collected from all rats. EGCG, at a concentration of 10 mg/kg, caused behavioral changes in rats similar to anxiety. In EPM, OVX rats spent less time in open arms than SHAM group rats and EGCG group rats (F = 16.043, p < .01). In OFT, the total travelled distance and the number of entries for EGCG group were higher compared with OVX group (F = 30.939, H = 13.107, respectively; p < .01). In addition, the distribution and composition of intestinal microflora in rats changed after ovariectomy. EGCG modulated the diversity of gut microbiota in OVX group at the phylum and the genus levels. Our results suggested that the composition of gut microbiota and anxiety in OVX rats were simultaneously affected by EGCG, and therefore, the two conditions might be strongly related, yet the deeper mechanistic links need further exploration.