Inhibitory Effect Of Lycopene On Male Reproductive Toxicity Induced By Nano Titanium Dioxide And Its Possible Mechanism

Objective:The research was done to investigate the effect of lycopene on the reduction of reproductive toxicity induced by Nano-TiO₂ in male mice,and reveal its related mechanisms from the perspective of oxidative damage and differential gene expression changes.The aims of this research were provide reference for the prevention of reproductive toxicity in male mice induced by Nano-TiO₂ exposure and the application development of lycopene.Methods:96 healthy male ICR mice were randomly divided into a control group,Nano-TiO₂ group?50 mg/kg BW?,lycopene groups in different dosages?5,20and 40 mg/kg BW?and Nano-TiO₂ mixed lycopene in different dosages groups?the dosage of Nano-TiO₂ in all groups was 50 mg/kg BW;The dosages of lycopene were 5,20and 40mg/kg BW respectively?,mice were sacrificed after 30 days of continuous gavage.Sperm count,sperm motility and sperm malformation in epididymis were determined.HE staining was used to observe the pathological changes of testis tissue and evaluate the pathological state of testis by TMI score.The ultrastructure of testicular tissue was observed by transmission electron microscope.The MDA content,SOD activity and anti-O₂^-level in mouse testicular tissue were determined with the kit.Differentially expressed genes in mice testicular tissue between Nano-TiO₂ group and Nano-TiO₂ mixed lycopene in 20 mg/kg BW dosage group were screened by transcriptome sequencing,and the genes were further analyzed GO functional classification and KEGG pathway enrichment.Results:1.Compared with those of control group,the sperm number,sperm motility rate and sperm progressive motility rate of male mice in the Nano-TiO₂ group were significantly reduced?P<0.05?,and the sperm malformation rate was significantly increased?P<0.05?.Compared with those of Nano-TiO₂ group,the intervention of 20mg/kg BW lycopene significantly increased sperm number?P<0.05?.After the intervention of 5,20 and 40mg/kg BW lycopene,sperm motility rate and sperm progressive motility rate were significantly increased,and sperm malformation rate was significantly reduced?P<0.05?.After exposure to Nano-TiO₂,the number of spermatogenic cells in the testicular spermatogenic tubules decreased,the vacuolation between spermatogenic cells in mice testicular tissue was serious,and the TMI score was significantly higher than that of control group?P<0.05?.Compared with that of Nano-TiO₂ group,Spermatogenic cells number in the spermatogenic tubules increased after the dosage of 20mg/kg BW lycopene intervening,the vacuolization between spermatogenic cells was significantly improved,and the TMI score was decreased.The ultrastructure of mice testis in Nano-TiO₂ group showed the phenomenon of supporting cytoplasmic dissolution and cell membrane shrinkage of adjacent germ cells,the degree of testicular injury was reduced and the shrinkage of adjacent reproductive cell membrane was improved in Nano-TiO₂ and 20mg/kg BW lycopene mixed group.2.Nano-TiO₂ exposure led to a significant increase in MDA content in mice testis tissue?P<0.05?,SOD and anti-O₂^-level decreased;after intervention with three doses of lycopene,MDA content was significantly reduced,anti-O₂^-level all increased significantly?P<0.05?.3.622 differentially expressed genes were screened in the 20mg/kg BW lycopene and Nano-TiO₂mixture group compared with that of the Nano-TiO₂ group,among which 280 genes were up-regulated and342 genes were down-regulated.Through the GO functional classification of differentially expressed genes,the enrichment entries participated in antioxidant processes such as glutathione peroxidase activity and oxidoreductase activity.The KEGG pathway enrichment analysis shows 16 signaling pathways were enriched by up-regulated differentially expressed genes,and the JAK-STAT pathway was closely related to the oxidation-antioxidant process.14 signaling pathways were enriched by down-regulated differentially expressed genes,including the glutathione metabolic pathway associated with oxidation-related enzyme metabolism.The protein interaction network indicates that the Akt1 gene is in the center of the protein regulatory network.Conclusion:Lycopene could inhibit male reproductive toxicity that the Nano-TiO₂ induced by reducing the oxidative damage in the testicular tissues of male mice.In addition,genes and signaling pathways related to oxidative damage play certain role in the antagonizing effect of lycopene on the male reproductive toxicity induced by Nano-TiO₂.