一氧化氮途径对大鼠精子发生的影响

Effect of nitric oxide pathway on spermatogenesis in rats

为阐明一氧化氮途径对精子发生的影响 ,探讨一氧化氮对精子发生的调节作用 ,将雄性SD大鼠分为 4组 ,分别于腹腔内注射左旋精氨酸 (L arginine ,L ARG)、N 硝基左旋精氨酸甲酯 (N nitro L arginine mythel ester,L NAME)、L ARG +L NAME与生理盐水 ,每天一次 ,共 1 2d。于最后一次注射后 2h采血并处死动物。放免法测定血清内睾酮含量 ;GREISS法测定血清NO-x (硝酸盐 亚硝酸盐 )含量 ;常规组织学切片观察生精上皮形态 ,并对Ⅶ -Ⅷ期生精上皮横断面的各级生精细胞进行定量分析 ;扫描电镜观察生精小管内精子密度。结果表明 :L ARG组血清内NO-x 含量高于对照组 (P <0 0 1 ) ,睾酮含量低于对照组 (P <0 0 1 ) ,精子生成减少 (P <0 0 1 ) ;L NAME组血清内NO-x 含量低于对照组 (P <0 0 1 ) ,睾酮含量高于对照组 (P <0 0 1 ) ,精子生成增加 (P <0 0 1 )。L ARG +L NAME组NO-x 与睾酮含量及精子的生成无显著性变化。因此 ,加强NO途径抑制精子发生 。

s: The objective of the present study was to evaluate prospectively the role of nitric oxide (NO) in modulating spermatogenesis. Fourty male rats(60～70days) were individed into four groups. Ten male rats were injected intraperitoneally one of following agents(once a day,for 12 days): (1) L arginine(L ARG); (2) N nitro L arginine mythel ester(L NAME); (3)L ARG+L NAME;(4)Normal saline. The blood samples were collected at two hours after postinjection and the rats were crucified. The concentration of serum testosterone was measured by radioimmunoassay. Serum NO - x(nitrite/nitrate) concentration was measured by Greiss method. The morphology of germs was observed with light microscopy.The various germs in seminiferous epithelium were counted at stage Ⅶ-Ⅷ.The density of spermatozoons in seminiferous tubule was observed with scaning electron microscopy. The results showed that NO - x concentration increased and testosterone concentration was lower compared with normal (saline) group with L ARG treatment,and spermatogenesis was suppressed( P <0.01). However, in rats treated with L NAME, significantly lower NO - x cencentration and higher testosterone concentration were observed in comparison with both L arg and nomal saline subjects( P <0.01). L NAME group demonstrated a significantly increased number of spermatids and spermatozoons per cross sectional area compared with L ARG and normal saline groups ( P <0.01). Electron microscopy revealed that spermatozoons in seminiferous tubules were denser in L NAME group than in L ARG and than in nomrmal saline groups. No change was observed in L ARG+L NAME group.Strengthened NO pathway promoted spermatogenesis and inhibited NO pathway suppressed spermatogenesis.