Some studies have found that nano-sized titanium dioxide (nano-TiO2) has adverse effects on the male reproductive system. Blood-testis barrier (BTB), as one of the tightest blood-tissue restriction, is crucial to the male reproductive system. However, the potential effects on BTB and signaling pathway changes in testis tissue induced by nano-TiO2 remain poorly understood. Therefore, in this study, 60 Institute of Cancer Research mice were divided randomly into four groups (per group = 15). The mice of four groups were intragastrically administered with 0, 10, 50, and 100 mg/kg BW nano-TiO2 respectively for 30 days to analyze the changes of BTB structure, BTB-related proteins, and MAPK signal pathways. Besides, testosterone level, estradiol level, and sperm parameter (sperm count, sperm motility, and sperm malformation rate) changes were also studied in this research. The results indicated that nano-TiO2 could induce the BTB structural damage and accompanied by the BTB main protein (ZO-1, Claudin-11, and F-actin) elevation of irritability. Nano-TiO2 could also activate the MAPK signaling pathways (p38, JNK, and ERK) of mice testis tissue. The testosterone and estradiol levels in serum reduced. Besides when the mice were administered with nano-TiO2, we also found the sperm motility rate decreased, and sperm malformation increased. The above changes may be associated with BTB damage and the activation of MAPK signaling pathways, thereby causing male reproductive dysfunction.
Keywords: Blood-testis barrier; MAPK signaling pathways; Nano-sized titanium dioxide; Spermatogenesis; Testis.