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为了探究母代大鼠孕前染砷(As_2O_3)对胎鼠睾丸前精原细胞的毒性作用及生殖发育潜能,将24只雌性SD大鼠随机分为3组(n=8),通过灌胃方式建立As_2O_3染毒模型后,按“一代一窝”繁殖试验技术获得后代。大鼠妊娠第17.5天时取材,碱性磷酸酶染色法鉴定睾丸前精原细胞,透射电镜技术观察前精原细胞超微结构变化,qRT-PCR检测生殖细胞发育相关基因vasa mRNA表达,从而分析前精原细胞的凋亡情况及发育潜能。试验结果显示,与对照组比较,随着孕前染As_2O_3剂量的增加,胞核染色质进一步凝缩成致密团块;粗面内质网减少,结构损害逐渐加重;线粒体肿胀、破裂增多,线粒体颗粒分布更少,电子密度进一步降低,呈空泡状坏死。试验组睾丸组织中vasa mRNA表达量下降,与对照组比较差异显著(P<0.05),vasa mRNA表达量下降程度与孕前染As_2O_3剂量呈一定的负相关。试验表明,雌性SD大鼠孕前所染As_2O_3可通过胎盘屏障进入胎儿血液循环,并穿透前精原细胞的胞膜和线粒体膜,影响线粒体结构发生改变,诱导前精原细胞发生凋亡,vasa mRNA表达量下降,从而引起胚胎生殖毒性,抑制生殖细胞发育。
In order to explore the toxicity and reproductive development potential of pre-pregnant arsenic (As_2O_3) on pre-pregnancy spermatogonia in female rats, 24 female SD rats were randomly divided into 3 groups (n = 8) After establishing the As_2O_3 model, the offspring were obtained according to the “one generation one nest” reproductive test technique. The pre-testicular spermatogonia were identified by alkaline phosphatase staining, ultrastructural changes of pre-spermatogonia were observed by transmission electron microscopy and the expression of vasa mRNA was detected by qRT-PCR. Spermatogonial cell apoptosis and developmental potential. The results showed that, compared with the control group, with the increase of dose of As_2O_3 during pregnancy, the chromatin of nucleus further condensed to a dense mass; the rough endoplasmic reticulum was reduced and the structural damage was gradually aggravated; mitochondria were swollen and ruptured, mitochondria granules Distribution less, the electron density to further reduce the vacuole-like necrosis. The expression of vasa mRNA in testis decreased in experimental group compared with that in control group (P <0.05). The decrease of vasa mRNA expression was negatively correlated with the dose of As_2O_3 in preimpregnation. Experiments show that female SD rats pre-pregnancy As_2O_3 can enter the fetal blood circulation through the placental barrier and penetrate the pre-spermatogonia membrane and mitochondrial membrane, affecting mitochondrial structure changes, pre-induction of apoptosis of spermatogonia, vasa mRNA expression decreased, resulting in embryonic toxicity, inhibit germ cell development.