The Researches On The Damage Mechanism Of Sub-Chronic Manganism On The Testis Of Chicken

Manganese is essential trace element for organisms, which plays an important role in growth, development and breeding, but excessive manganese disturbs nervous, immune, respiratory and genital systems and results in manganis. The researches about manganism mainly focused on nervous and immune systems, not on genital system. The reports of genital system mainly focused on human and mouse not on poultry. In the study, 600, 900, 1800 mg/kg MnCl2 were addde to forage to establish the model of the sub-chronic manganese poisoning and after 30d, 60d and 90d, testicles were taken out. Clinical symptoms, anatomy, microstructure and ultrastructure were observed, contests of Mn, Fe, Ca, Cu and Zn in testis, oxidative stress, activities of LDH, SDH and ATPase, levels of T, LH and FSH in serum, expression of LHR and FSHR mRNA, DNA damage, DPC and cells apoptosis were measured to assess the effect of manganism on male genital function of cock and clarify preliminary toxicity mechanism of manganism to male genital system. The results showed as follows:1. The orbervation of microstructure and ultrastructure confirmed that manganese could induce testis tissue damage and the morphology change of spermatogenic cells, which indicated that manganese could induce the apoptosis of spermatogenic cells to affect the genital function.2. By detecting the content of Mn, Fe, Ca, Cu and Zn in testis, the content of Mn increased and the content of Fe, Ca, Cu and Zn decreased. The results showed that manganese could cumulate in testis, and then affect other mineral matter content and the production and maturate of sperm.3. Excessive manganese induced the oxidative stress of testis, increased the activity of NOS and the content of NO and carbonyl and destroyed antioxidative defense system of organism, removed the free radical and induced testis oxidative damage.4. The decreasing activities of LDH, SDH and ATPase in testis reflected the interference to energy metabolism of mitochondria from manganism.5. Excessive manganese increasing the content of DPC confimed that manganese could create the genetic damage of DNA .6. Excessive manganese decreased the content of T, FSH, LH and the expression of LHR and FSHR mRNA, which confirmed that excessive manganese could disordered the endocrine and affected the development of testis spermatogenic cells. It verified further that Excessive manganese the transcription of gene which promotes the development of spermatogenic cells. It might be one reproduction toxicity mechanism of manganese.It was concluded that manganism can make influence on male genital function of cock, cause testis histopathology damage, interfere in energy metabolism of mitochondria, affect oxidative stress, induce the apoptosis of spermatogenic cells and alter mRNA expression of LHR and FSHR. The influence on energy metabolism, inducement of apoptosis and interference in gene expression maybe involved in the mechanism of manganism.