稀土颗粒物Nd_(2)O_(3)暴露对C57 BL/6J雄性小鼠性激素分泌及CYP11A1/PLZF/STRA8蛋白表达的影响

Effects of Nd_(2)O_(3) exposure of rare earth particles on C57 BL/6J male mice sex hormone secretion and CYP11A1/PLZF/STRA8 protein expression

目的探讨稀土颗粒物Nd_(2)O_(3)暴露对C57 BL/6J雄性小鼠性激素分泌及胆固醇侧链裂解酶(CYP11A1)、减数分裂前精子发生标志物早幼粒细胞白血病锌指蛋白(PLZF)和视黄酸刺激基因(STRA8)蛋白表达的影响。方法于2021年3月,将48只6~8周龄雄性C57 BL/6J小鼠分为对照(Control)组和Nd_(2)O_(3)低、中、高剂量组(染毒剂量分别为62.5、125.0、250.0 mg/ml Nd_(2)O_(3)),每组12只。采用一次性非暴露式气管滴注法对Nd_(2)O_(3)组小鼠灌注0.1 ml不同剂量的Nd_(2)O_(3)混悬液,对照组灌注等体积的生理盐水。染毒后28 d称量小鼠体重、睾丸及附睾的重量,并计算脏器系数;取两侧附睾制成精子悬液测定精子数量、存活率、畸形率;采用电感耦合等离子体质谱(ICP-MS)法检测小鼠睾丸组织中Nd的含量;HE染色检测睾丸组织病理形态学改变并做量化分析;酶联免疫吸附(ELISA)法检测各组小鼠血清促黄体生成素(LH)、促卵泡生成素(FSH)和睾酮(T)的含量;Western blot法检测睾丸组织中CYP11A1、PLZF和STRA8的表达水平。结果与对照组比较,随着染毒剂量的升高,小鼠睾丸内Nd含量呈现升高趋势,精子存活率和LH呈现降低趋势,精子畸形率呈现升高趋势(P<0.05);病理学结果显示,Nd_(2)O_(3)中、高剂量组睾丸组织生精小管内精子数量明显减少,出现生发上皮解体、上皮内空泡化、生精细胞和支持细胞剥落的现象;随着染毒剂量升高,其生发上皮高度明显降低,受损伤的生精小管所占百分比呈现升高趋势(P<0.05);Nd_(2)O_(3)中、高剂量组小鼠血清中FSH和T水平,睾丸组织中CYP11A1、PLZF和STRA8的蛋白水平随剂量的升高呈现下降趋势(P<0.05)。结论稀土颗粒物Nd_(2)O_(3)可能通过干扰CYP11A1、PLZF和STRA8蛋白的表达,导致体内性激素分泌紊乱、精原细胞的维持及减数分裂过程受阻,引起生殖功能损伤。

Objective To explore the effects of Nd_(2)O_(3)exposure to rare earth particles on the secretion of sex hormones,cytochrome P450 family member 11A1(CYP11A1),spermatogenesis markers promyelocytic leukemia zinc finger protein(PLZF)and retinoic acid stimulating gene 8(STRA8)protein in C57 BL/6J male mice.Methods In March 2021,Forty-eight male C57 BL/6J mice aged 6-8 weeks divided into control group and Nd_(2)O_(3)exposure low,medium and high dose groups(exposing doses of 62.5,125.0,250.0 mg/ml Nd_(2)O_(3)),12 per group.The mice in the Nd_(2)O_(3)groups were perfused with different doses of Nd_(2)O_(3)suspension by a one-time non-exposing tracheal instillation method,and the control group was perfused with an equal volume of normal saline,with a volume of 0.1 ml,to establish a mouse reproductive function injury model.After 28 days of exposure,the mice's body weight,testes and epididymis were weighed,and the organ coefficients were calculated;the two epididymis were taken to make a sperm suspension to determine the sperm count,survival rate,and deformity rate;inductively coupled plasma mass spectrometry(ICP-MS)method was used to detect the content of Nd in mouse testis tissue;HE staining was used to detect testicular tissue pathological changes and quantitative analysis;enzyme-linked immunosorbent assay(ELISA)method was used to detect serum luteinizing hormone(LH)and follicle stimulating hormone(FSH)and testosterone(T)content;western blot was used to detect the protein levels of CYP11A1,PLZF and STRA8 in testicular tissues.Results Compared with the control group,with the increase of the exposure dose,the Nd content in the testis of the mice showed an increasing trend,the sperm survival rate and LH showed a decreasing trend,and the sperm deformity rate showed an increasing trend(P<0.05);Pathological showed that the number of sperm in the seminiferous tubules of the testicular tissue in the Nd_(2)O_(3)medium and high dose groups was significantly reduced,and the germinal epithelial disintegration,intraepithelial vacuolization,and exfoliation of spermatogenic cells and supporting cells occurred;The height of germinal epithelium was significantly reduced,and the percentage of damaged seminiferous tubules showed an increasing trend(P<0.05);FSH and T levels in serum in the middle and high dose groups of Nd_(2)O_(3),and CYP11A1,PLZF and STRA8 proteins in testicular tissues showed a downward trend with increasing dose(P<0.05).Conclusion The rare earth particulate Nd_(2)O_(3)may interfere with the expression of CYP11A1,PLZF and STRA8 protein,thereby causing the disorder of sex hormone secretion in the body,the maintenance of spermatogonia and the obstruction of the process of meiosis,causing reproductive function damage.