| Objective:Zearalenone(ZEA)is a kind of nonsteroidal mycotoxin with estrogenic effects.It can be found in many kinds of cereal and cereal products,which are collected from many countries all over the world.It can remain its stability even in heated food.It can influence animal reproductive capacity through interfering with the estrogen signaling pathway.Previous studies have shown that exposure to ZEA at high doses(higher than No-Observed Effect Level,NOEL)had a significant impact on mice sperm quality,apoptosis,spermatogenesis,integrity of DNA and pregnant rate.Most studies focus on the effect of exposure to ZEA with unnatural way at high dose,little is known about the effect of exposure to ZEA with natural way at lower doses(lower than NOEL)on mice reproductive capacity.This study evaluated the effects of low-dose ZEA exposure on mice spermatogenesis and semen quality.Methods:1.90 male mice(CD-1)of 21 days were divided randomly with random number table into three groups,which were defined as 0?g/(kg·d)group,20?g/(kg·d)group and 40?g/(kg·d)group.2.Each group was exposed to ZEA at 0,20,and 40 ?g/kg b.w.for 14,28 and 42 days respectively.3.We analyzed the changes in sperm motility,sperm concentration and hyperactivity et.al via Computer-aided sperm analysis(CASA).4.Followed by counting under microscope,giemsa staining was performed for analysis of sperm defect rate.5.Cell apoptosis and necrosis assay kit was used for analysis of sperm viability.6.Testis quality and volume were examined to assess the development of testis.7.Immunohistochemical staining was performed on paraffin section of testis to observe the seminiferous tubules.The count of spermatogenic cells per area unit and diameter of seminiferous tubules were collected to evaluate spermatogenesis.8.Immunofluorescent staining was performed on spermatogenic cells to evaluate the DNA double-strand breaks.Results:1.After exposure to ZEA for 14 days,28 days and 42 days,sperm motility,sperm concentration and hyperactivity of mice in 20?g/(kg·d)group and 40?g/(kg·d)group decreased dose-dependently,compared with that in 0?g/(kg·d)group.After 42 days exposure to ZEA,the difference between each group was significant.2.After 42 days exposure to ZEA,the sperm defect rate were significantly higher in 20?g/(kg·d)group and 40?g/(kg·d)group compared with that in 0?g/(kg·d)group.The difference was dose-dependent.3.After 42 days exposure to ZEA,the dead sperm rate were significantly higher in 20?g/(kg·d)group and 40?g/(kg·d)group compared with that in 0?g/(kg·d)group.The difference was dose-dependent.4.The testis quality in 20?g/(kg·d)group and 40?g/(kg·d)group were significantly lower compared with that in 0?g/(kg·d)group.The difference in testis quality was also dose-dependent.5.The testis volume in 20?g/(kg·d)group and 40?g/(kg·d)group were significantly lower compared with that in 0?g/(kg·d)group.The difference in testis volume was also dose-dependent.6.As the spermatogenic cells in seminiferous tubules,after treatment for 14 days,the decline was dose-independent;however after treated by ZEA for 28 days,the spermatogenic cells in per area unit in seminiferous tubules in 20?g/(kg·d)group and 40?g/(kg·d)group declined dose-dependently,and the difference between each group was significant.However there was no significant deference in the diameter of seminiferous tubules between each group.7.In 20?g/(kg·d)group and 40?g/(kg·d)group,the DNA double stand break(DSB)of spermatogenic cells increased in a dose dependent manner during the initial meiosis,after treated for 14 days,28 days and 42 days,compared with the 0?g/(kg·d)group.The difference between each group was significant.Conclusion:1.Low dose ZEA exposure impaired semen quality of male mice.2.Low dose ZEA exposure disturbed spermatogenesis of male mice.3.Low dose ZEA exposure influenced testis development.4.Low dose ZEA exposure induced DNA DSBs in initial meiosis of male mice.5.DNA DSBs induced by low dose ZEA exposure may be one of the reason of the impairment of spermatogenesis and semen quality. |
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