慢性镉负荷雄性大鼠的睾丸及生殖内分泌功能活动

选择健康SD雄性成年大鼠60只,随机分成对照组（C组）、镉负荷中剂量组（M组）和镉负荷高剂量组（H组）,每天分别饲喂含镉0,5,10mg/kg的大鼠全价饲料,连续6周,研究了镉负荷对大鼠睾丸及生殖内分泌功能活动的影响。结果显示：在整个实验期内,M和H组大鼠睾丸组织中的镉含量极明显上升,锌含量销有下降,与对照组差异不显著;血浆镉、锌含量虽分别表现稍有升高和下降,但与对照组比较无明显差异;H组睾丸精子头计数和每日精子生成量在镉负荷第3周极显著下降,第6周时,M和H组均极明显低于对照组;在整个实验期内,H组大鼠ALP活明显低于C组;LDH－X活性在M和H组大鼠均极明显低于C组;M和H组血浆T水平下降,均低于或显著低于C组;3组间的FSH和LH水平无明显差异。结果提示：慢性镉负荷在睾丸组织中逐步蓄积可引起睾丸一些酶活性改变、精子生成减少及内分泌功能活动低下。

Effects of chronic cadmium loading on the testis and endocrine function of reproduction in male rats

Sixty healthy Sprague-Dawley male rats were used and divided randomly into control group (group C), cadmium loading group with medium dose (group M) and cadmium loading group with high dose (group H). Groups C, M and H were orally dosed daily with 0, 5 and 10 mg/kg of cadmium for over 6 weeks. Effects of cadmium loading on testis and endocrine function of reproduction in male rats were studied. The results showed that the zinc content decreased slightly in testis and plasma, and the cadmium concentration increased significantly in the testis of groups M and H; while the plasma levels of cadmium and zinc had no obvious difference as compared with those of group C; daily sperm production in the testis of group H decreased markedly during week 3 of cadmium loading, and was significantly lower in groups M and H as compared to that in group C during week 6; alkaline phosphatase (ALP) in group H and lactate dehydrogenase-X (LDH-X) in groups M and H were markedly lower compared to those of group C; plasma testosterone (T) level in both cadmium loading groups decreased and was low or significantly lower than that in group C; follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels had no apparent difference between the three groups. It is suggested that the gradual accumulation of cadmium in testis tissue induced by chronic cadmium loading results in changes in some en- zyme activity, a decrease in sperm production, and defect of endocrine function activity in the testis.