甲基睾酮对雌性斑马鱼性腺发育的抑制作用

Inhibiting effect of methyltestosterone on gonad development of female Zebrafish(Danio rerio)

用含雄性激素甲基睾酮(MT)的饲料饲喂经产雌性斑马鱼(Danio rerio)来探讨外源激素对其性腺发育的影响。通过投饲含0、30、60、120、240和400 mg.kg-1 MT的饲料30 d后,石蜡切片观察斑马鱼卵巢的发育情况。结果表明,随着MT剂量的增加,斑马鱼性腺的发育受到抑制,卵巢结构变化明显。30 mg.kg-1剂量组的成熟系数有明显的降低,至400 mg.kg-1剂量组,成熟系数仅为对照组的1/6;同时外源雄性激素严重影响或抑制了卵巢的进一步发育,较低剂量组性腺发育停滞在Ⅲ时相左右,较高剂量组的性腺明显的退化,至400 mg.kg-1剂量组,卵巢已呈明显的萎缩状态,卵母细胞几乎不可见;卵母细胞在甲基睾酮作用下的退化过程为:抑制卵母细胞发育—细胞核结构变化—累及细胞器—形成凋亡小体、破坏细胞膜结构—凋亡小体逸散、细胞固缩—崩解。结果显示外源雄性激素对雌性斑马鱼的性腺发育影响明显,较高剂量时可导致外源激素的阉割作用。

Using the feed involved Methyltestosterone（MT） to feed multiparity female Zebrafish（Danio rerio） for 30 d to detect the effect of foreign hormone on the gonad development.After 30 d feeding by the diet which contained 0,30,60,120 and 240 and 400 mg·kg-1 MT,paraffin sections were made to observe the development of ovary.Results showed that,with MT dosage increased,the gonadal growth of the females were obviously inhibited,and the ovarian structure changed obviously.At the dosage of 30 mg·kg-1,the maturity ratio dropped comparatively to the control.When the treated dosage rised to 400 mg·kg-1,the maturity ratio was only obove 1/6 to the control group.Meanwhile,the foreign MT inhibited the ovarian development.For lower dosage treatments,they were stopped at the III phase.And the higher dosage treatments,the ovaries w retrogression.In the group of 400 mg·kg-1,there was even no ovocyte could be found.The ovocyte retrogression was as follows： inhibition-structure change in nuclear-cellular organ disintegration-apoptosis body formed,memberance destroy-apoptosisi body dissipation-disintegration.Therefore,at some dosages,the foreign MT would inhibite the gonard development and the high content MT feed could castrate the fish.