GT Urological (United States)

Abstract Introduction Background: The male reproductive seminal microbiome is associated with male infertility in work by our group and others, and preliminary data from our lab suggests that the presence of a varicocele further alters local male reproductive microbiome. To date, no published data has directly assessed the anatomic distribution of these resident bacteria within the testicle, epididymis, or elsewhere in the reproductive tract. Objective This study aimed to investigate and quantify changes in bacterial presence within different compartments of the male reproductive system following experimentally induced varicocele. Methods Fresh tissue samples from the left and right testicle and epididymis were obtained from rats following an established surgical varicocele induction model and compared to healthy controls.. Samples were fixed, sectioned and stained with a universal FISH probe capable of identifying bacteria (EUB338) and counterstained with DAPI for nuclear visualization and anti-smooth muscle actin antibody to delineate tissue architecture. Images were captured using fluorescence and confocal microscopy. Bacterial counts per square millimeter (mm2) were quantified for each sample group. A Kruskal-Wallis Test and Post-Hoc Bonferroni correction were used to determine statistically significant differences. Results Quantitative analysis revealed no statistically significant difference in bacterial load between epididymis and testicle in healthy rodents (p > 0.05). However, a significant increase (p < 0.0001) in bacterial density was observed in testicular tissue in animals with varicocele compared to controls. These bacteria primarily localized to the lumen. Conclusions The findings clearly confirm the presence of a resident local testicular microbiome even in the absence of clinical infection and suggest that the presence of a varicocele directly increases testicular bacterial content compared to controls. These findings suggest that the pathophysiological effect of varicocele may be due in part to disruptions in the local microbial homeostasis. Further work is necessary to characterize these resident bacteria further and to identify diagnostic and novel treatment strategies to restore fertility in men with varicocele. Disclosure No