低剂量纳米氧化镍亚慢性染毒对雄性大鼠生殖功能及子代的影响

Impact of subchronic exposure to low-dose nano-nickel oxide on the reproductive function and offspring of male rats

目的:研究低剂量纳米氧化镍亚慢性染毒对雄性大鼠生殖功能及雌性大鼠胚胎发育的影响。方法:将50只健康雄性SD大鼠(180~220 g)按体重采用随机数字表随机分为5组,每组10只,分别为生理盐水对照组(阴性对照组)、微米氧化镍组(4.0 mg/ml,阳性对照组)及纳米氧化镍低、中、高剂量组(浓度分别为0.16、0.8、4.0 mg/ml);以非暴露式气管滴注法染毒,1次/3d,60 d后与正常成年雌性大鼠按1∶2合笼。确定雌鼠怀孕后,处死雄鼠,称量雄性大鼠体重、睾丸、附睾,计算脏器系数;检测附睾精子浓度及活精子率,采用原子荧光谱法测定血液和精液镍含量;于妊娠第20天处死雌鼠,观察雌雄交配受孕情况、受精卵着床数、活胎数、死胎数及吸收胎数。结果:染毒60 d后,与阴性对照组和微米氧化镍阳性对照组相比,各剂量纳米氧化镍组大鼠体重,睾丸、附睾重量及其脏器系数均无显著差异。与阴性对照组相比,中、高剂量纳米氧化镍组大鼠精子浓度[(7.49±1.46)、(6.30±1.36)×10^6/ml vs(9.36±0.98)×10^6/ml,P<0.05]和活精子率[(68.26±16.63)%、(65.88±14.68)%vs(85.35±9.16)%,P<0.05]显著下降,畸形精子率显著升高[(13.99±4.87)%、(15.38±8.86)%vs(8.30±2.47)%,P<0.05];与阴性对照组相比,中、高剂量纳米氧化镍组孕鼠的吸收、死胎率显著增高(6.89%、7.37%vs 1.18%,P<0.05);与阴性对照组相比,中、高剂量纳米氧化镍组大鼠血液镍[(0.52±0.34)、(0.82±0.44) mg/L vs(0.13±0.16) mg/L,P<0.05]和精液镍[(0.35±0.23)、(0.63±0.61) mg/L vs(0.08±0.13) mg/L,P<0.05]显著升高;相关性分析结果显示,血液镍和精液镍含量显著相关(r=0.912,P<0.01),精液镍含量与活精子率呈负相关(r=-0.879,P<0.01),而与畸形精子率呈正相关(r=0.898,P<0.01)。结论:0.16 mg/ml纳米氧化镍染毒对大鼠生殖功能未见明显的毒性作用,0.8、4.0 mg/L纳米氧化镍染毒60 d可对雄性大鼠产生生殖毒性,并对胚胎有一定的致畸作用。

Objective: To investigate the influence of subchronic exposure to low-dose subchronic nano-nickel oxide (NNO) on the reproductive function of male rats and embryonic development of the pregnant rats. Methods: Fifty normal healthy male SD rats weighing 180 -220 g were randomly divided into five groups of equal number, negative control, 4 mg/ml micro-nickel oxide (MNO), and 0.16, 0.8 and 4 mg/ml NNO, those of the latter four groups exposed to MNO or NNO by non-contact intratracheal instillation once every 3 days for 60 days, and then all mated with normal adult female rats in the ratio of 1:2. After the female animals were confirmed to be pregnant, the males were sacrificed and the weights of the body, testis and epididymis obtained, followed by calculation of the visceral coefficients, determination of epididymal sperm concentration and viability and the nickel contents in the blood and semen by atomic fluorescence spectrometry. The female rats were killed on the 20th day of gestation for counting of the implanted fertilized eggs and live, dead and resorbed fetuses. Results: After 60 days of exposure, the rats of the NNO groups showed no statistically significant differences from those of the negative control and MNO groups in the weights of the body, testis and epididymis or visceral coefficients. Compared with the negative control group, the animals of the 0.8 and 4 mg/ml NNO groups exhibited markedly decreased sperm concentration ([9.36 ± 0.98] vs [7.49 ± 1.46] and [6.30 ± 1.36]×10^6/ml, P < 0.05) and viable sperm ([85.35 ± 9.16]% vs [68.26 ± 16.63]% and [65.88 ± 14.68]%, P< 0.05), increased morphologically abnormal sperm ([8.30 ± 2.47]% vs [13.99 ± 4. 87]% and [ 15.38 ±8.86]%, P < 0.05), and elevated rate of dead and resorbed fetuses ( 1. 18% vs 6.89% and 7.37%, P < 0.05), blood nickel content ([0. 13 ± 0. 16] vs [0.52 ± 0. 34] and [0.82 ± 0.44] mg/L, P <0.05) and semen nickel content ([0.08 ± 0.13] vs [0.35 ±0.23] and [0.63 ± 0.61 ] mg/L, P < 0.05). The nickel level in the semen was correlated significantly with that in the blood (r = 0.912, P <0.01), negatively with the rate of viable sperm (r =-0. 879, P <0.01 ) and positively with the percentage of morphologically abnormal sperm (r =-0. 898, P <0.01). Conclusion:Sixty-day exposure to nano-nickel oxide at 0.8 and 4 mg/ml can produce reproductive toxicity in male rats and result in fetal abnormality in the females, while that at 0. 16 mg/ml has no significant toxic effect on the reproductive function of the males.