半乳糖凝集素-3在邻苯二甲酸二丁酯致大鼠尿道下裂发生中的表达

Differential expression of galectin-3 in the hypospadiac male rats induced by Di-n-butyl phthalate

目的 利用邻苯二甲酸二丁酯（DBP）胚胎期暴露导致SD大鼠尿道下裂发生的动物模型,观察半乳糖凝集素-3（galectin-3）在尿道下裂与正常大鼠生殖结节中的差异表达,探讨其在DBP致大鼠尿道下裂发生中的作用.方法 SD孕鼠20只,随机分为2组,妊娠14～18 d（GD14～18）实验组和对照组分别给予DBP 800 mg/（kg·d）和大豆油2 ml/d灌胃,GD19剖宫产后统计子鼠数、雄性子鼠出生体质量（BW）及肛门生殖器距离（AGD）、尿道下裂发生率,取两组雄性子鼠生殖结节,运用免疫印迹法和免疫组织化学方法分析galectin-3的表达.结果 尿道下裂仅实验组发生,发生率为40%,每窝子鼠数、雄性子鼠BW及AGD/BW在实验组分别为（8.90±1.25）只、（5.12±0.24）g、（0.57±0.03）mm/g,在对照组分别为（13.20±1.46）只、（6.72±0.42）g、（0.66±0.07）mm/g,差异有统计学意义（P＜0.05）;galectin-3在尿道下裂组的相对表达量为0.603±0.014（n=10）,正常对照组为0.851±0.015（n=10）,差异有统计学意义（P＜0.05）;galectin-3主要定位于生殖结节上皮细胞,尿道下裂组染色强度明显弱于对照组.结论 染毒期间DBP对雄性子鼠有明显毒性作用,改变了生殖结节中galectin-3的表达,影响了上皮细胞增殖、凋亡及尿生殖褶的融合.

Objective To verify the differential expression of galectin-3 in the genital tubercle （GT） of hypospadiac rats induced by maternal exposure to Di-n-butyl phthalate （DBP） and normal control rats in order to further explore the mechanism of hypospadias. Methods Twenty pregnant SD rats were randomly divided into two groups which were given DBP and soybean oil gavage at the dose of 800 mg/（kg·d） and 2 ml/d separately during the 14-18th day of pregnancy. Fetal rats per fossa, birth weight （ BW） , ano-genital distance （AGD）, hapospadias incidence, and harvested GT of fetal rats at GD19.The expression of galectin-3 was analyzed by Western blotting and immunohistochemistry. Results The incidence of hypospadias was 40% , the rat offspring per litter in experiment group was significantly less than in control group （P 〈 0.05）, （experiment group of 8.90 ± 1.25, control group of 13.20 ± 1.46） , BW and AGD/ BW of male offspring in control group were （6.72 ±0.42） g, （0.66 ±0.07） mra/g, those in experiment group were （5.12 ±0.24） g, （0.57 ±0.03） mm/g, and the expression of galectin-3 had statistically significant difference （P 〈 0.05）. Galectin-3 was mainly located in the cytoplasm of epithelium, and staining intensity in control group was stronger than in experimental group. Conclusion Maternal exposure to DBP can reduce the galectin-3 expression in GT epithelium, affect cellular proliferation, apoptosis and urethral fold fusion, and finally result in the occurrence of hypospadias.