TNF and chronic endometritis: With respect to the mRNA expression and levels of cytokine and inflammatory factors such as TNF-α, CD38, and IL1β, uterine inflammation was significantly higher in rats transplanted with the vaginal microbiota of women with chronic endometritis (P < 0.05, Student’s t-test) than in those transplanted with microbiota from the healthy group and in the control group (Fig. 5g and Supplementary Fig. 9).