Fig. 2

Effect of E. coli and human NPs on testis histopathology. a The testes from control mice showed normal morphology and spermatogenesis. H&E, reduced from ×200. b and c At 2 weeks, significantly leukocytic infiltration changes in the innermost layer of sperm cells were noted in groups B and C (Fig. 2b and c; red arrows). In addition, the innermost layer of sperm cells were structurally impaired and a zone of concentrically layered collagen fibers around the human NPs body was formed in the lumen of the seminiferous tubule in group C (Fig. 2c; yellow arrow). H&E, reduced from ×400. d At 4 weeks after infusion, seminiferous tubule was atrophic and a well-recognised form of intratesticular calcification surrounded by cellular debris within the seminiferous tubules was observed in group C only (white arrow), indicating a model of TM phenotype successfully reproduced. H&E, reduced from ×400