*3.2. Chronic Pelvic Pain*

Chronic pelvic pain (CPP) is a long-lasting pain that lowers quality of life, with many possible causes, such as endometriosis or chronic bacterial prostatitis [75,76]. Recent discoveries regarding the gut microbiome and visceral pain led to hypotheses about the correlation between CPP and the human microbiota. Shoskes et al. determined that patients with CPP had lower gut microbiota diversity than the control group, especially amongst *Prevotella* [77]. A study by Du et al. created a mouse model with experimental autoimmune prostatitis (EAP). EAP mice developed changes in the gut microflora, resulting in a distorted balance in Th17/Treg cells and decreased levels of short-chain fatty acids (SCFAs) in both serum and feces. Microbiota of healthy mice had notably fewer *Firmicutes*, *Nitrospirae*, or *Fusobacteria* than those with EAP. Additionally, the EAP mice had bacteria producing SCFAs, including *Bacteroides*, *Butyricicoccus*, and *Ruminococcaceae*. Changes in Th17/Treg balance were later reversed by supplementation of the SCFA propionate [78]. Their findings were consistent with other studies regarding chronic non-bacterial prostatitis [79,80]. Pelvic allodynia may also be caused by deficient lipase acyloxyacyl hydrolase (AOAH), an enzyme present in microglia. A study by Rahman-Enyart et al. suggests that AOAH plays a role in the modulation of pelvic pain, and its production is dependent on changes in the gut microbiome [81]. As new studies show, the microbiota is a crucial part of overall health, and its changes are correlated with many illnesses; however, further research is needed to make a comprehensive understanding of this topic possible.
