静磁场对体外三维培养小鼠腔前卵泡发育成熟的影响

Effects of static magnetic field on proliferation of mouse preantral follicles 3D cultured in vitro

目的:用三维小鼠腔前卵泡体外培养成熟体系检测静磁场对生殖细胞发育成熟的影响。方法:从12日龄昆明小鼠的卵巢中,机械分离出直径为(130±10)μm的腔前卵泡,用海藻酸钠凝胶将单个卵泡包埋后,放入预平衡的培养液滴中培养,并随机分成对照组、5和450 mT暴磁组,隔天半量换液,在倒置显微镜下测量其直径,连续培养8 d,对成腔的卵泡进行体外人绒毛膜促性腺激素(HCG)刺激16～18 h后,检测卵母细胞成熟情况。结果:各组卵泡形态学发育均良好,随着体外培养时间的延长,卵泡逐渐增大,在第4天450 mT暴磁组卵泡直径与对照组相比增大显著(<0.05),第6天5和450 mT暴磁组均明显高于对照组(P<0.05)。随着磁场强度增强,卵泡成腔率亦比对照组显著提高(P<0.05)。而5 mT暴磁组成熟率与对照组相比无明显变化(P>0.05),但450mT组与对照组相比显著降低(P<0.05)。结论:海藻酸盐凝胶可维持昆明小鼠腔前卵泡体外正常生长发育。随着磁场强度增强,卵泡的成腔率显著性提高,成腔卵泡直径显著增大,但高强度的静磁场可能会影响卵母细胞的成熟过程。

OBJECTIVE： The reproductive toxicity of static magnetic field （SMF） was investigated using mouse preantral follicle 3D culture in vitro system established in our laboratory. METHODS：Ovaries was removed from 12 days old female mice. （130±10）μm preantral follicles were isolated and encapsulated into alginate hydrogel,then cultured in droplets for 8 days. Experimental groups were treated by different intensity （5 and 450 mT） SMF. Diameter of follicles was measured every other day. The ovulation of antral follicles was induced by HCG hormone,and the matured oocytes （first polar body emission） were identified under the stereomicroscope. RESULTS：Follicles in each group were well developed on morphologically. Follicular diameter of each group gradually increased with culture time. Follicular diameter of 450 mT SMF-treated group was significantly increased at 4 days （P〈0.05）,and diameter of 5 and 450 mT SMF-treated group was significantly increased at 6 days（P〈0.05）,compared with that of control group. With the increasing intensity of SMF,the cavity formation rate of the follicles was obviously elevated,but the oocytes maturation rate of 450 mT SMF-treated group was significantly reduced compared with that of the control group. CONCLUSION：The alginate hydrogel could maintains the 3D structure of individual mouse follicle. With increasing strength of SMF,the diameter of secondary follicles was statistically increased,the cavity formation ratio was also markedly increased,but the process of oocyte maturation was inhibited by 450 mT SMF.