Alleviative Effect of Vaginal Lactobacilli with Probiotic Potential from Healthy Chinese Women on Bacterial Vaginosis Caused by Gardnerella vaginalis in Mice.

The main treatment strategy for bacterial vaginosis (BV) is antibiotic therapy, but they are not effective in restoring the vaginal microecology, which can lead to recurrence. This study aimed to isolate the dominant lactobacilli strains from the vagina of healthy Chinese women, evaluate their potential probiotic properties and explore their alleviative effect on BV infected mice. Our study isolated 43 strains of vaginal-dominant Lactobacillus. Four strains of Lactobacillus. crispatus, four strains of Lactobacillus. gasseri, and two strains of Lactobacillus. jensenii showed strong inhibitory effects on Gardnerella vaginalis and were safe in vitro. Subsequently, through principal component analysis on seven functional indicators of these 10 strains, Lact. crispatus G-7, Lact. gasseri B-5, and Lact. jensenii M-1 ranked the top beneficial strains and were finally selected as the candidate therapeutic strain for in vivo experiments. Animal experiments showed that Lact. crispatus G-7 was superior to other Lactobacillus species and the positive control metronidazole in restoring vaginal health (pH and HO). Additionally, it also significantly reduced the expression of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α while increasing the expression of anti-inflammatory cytokine IL-10. H&E staining and 16S rRNA gene sequencing showed that Lact. crispatus G-7 can alleviate the inflammatory damage caused by G. vaginalis and restored vaginal microecology. Among the isolated dominant Lactobacillus strains from the vagina, Lact. crispatus G-7 has been identified as the most effective in the treatment of G. vaginalis imparted BV. This strain is therefore a candidate for developing promising treatments for BV.