Photobiomodulation with mild thermal effects for the regulation of vaginal probiotics and inflammation in vaginitis

Vaginitis is characterized by microbial dysbiosis and chronic inflammation of the vaginal mucosa. Due to the anatomical and microbiological proximity between the vagina and urinary tract, vaginal dysbiosis and inflammation are often associated with an increased risk of urinary tract infections and other urological complications. Photobiomodulation (PBM), particularly when combined with mild thermal energy, has recently gained attention for its anti-inflammatory effects and its potential to modulate microbial communities in mucosal tissues. This study aimed to investigate the therapeutic potential of 808nm PBM with mild thermal effect in increasing vaginal probiotics and reducing inflammation in a vaginitis model. To determine the laser irradiation condition, ex vivo temperature evaluation was conducted using porcine vaginal tissue. Vaginal probiotic bacteria, Lactobacillus crispatus and Lactobacillus gasseri were used to assess the proliferative effects of PBM on in vitro bacteria. An in vivo vaginal infection model was used to determine the influences of PBM with mild thermal effect in reducing inflammation and modulating vaginal probiotics. Under 1 W/cm2 of 808nm PBM exposure, in vitro bacterial viability assays demonstrated a significant increase in the viability of L. crispatus and L. gasseri after 48 hours. In addition, PBM applied to the vagina in an in vivo vaginitis model effectively reduced inflammation in vaginal tissues and colony formation of C. albicans in vaginal fluid. Further studies will investigate the potential of PBM combined with mild thermal effects to improve the vaginal microbiome, thus providing an effective therapeutic strategy for the treatment of vaginitis.