十溴二苯乙烷对大鼠内分泌干扰效应的研究

发布时间：2018-05-23 19:43

本文选题：DBDPE + 甲状腺激素　；参考：《广西医科大学》2013年硕士论文

【摘要】：研究目的观察十溴二苯乙烷(decabromodiphenyl ethane, DBDPE)经口灌胃染毒后对青春期雄性大鼠甲状腺组织的影响,通过测定染毒后甲状腺激素3,5,3’三碘甲腺原氨酸(triiodothyronine, T3)、3,5,3',5'-四碘甲状腺原氨酸(thyroxine, T4)和促甲状腺激素(thyroid stimulating hormone, TSH)含量以探讨其甲状腺毒性；通过测定DBDPE染毒后肝脏微粒体代谢相关酶尿二磷酸葡萄糖醛酸转移酶(uridine diphosphate glueuronsyl transferases, UDPGTs)活性及对甲状腺和垂体特异性基因的影响以探讨甲状腺毒性作用机制；同时研究DBDPE对雄性大鼠青春期发育的影响,为全面了解DBDPE内分泌干扰效应和DBDPE的安全使用提供基础毒理学资料。研究方法 1.选取DBDPE制备染毒液,将出生后(postnatal day, PND)23天雄性大鼠按体重随机分为组：对照组、100mg/kg组、300mg/kg组、600mg/kg组,每组9只。采用经口灌胃染毒方式连续染毒至PND53,给药期间每日称量体重并根据体重适当调整给药剂量。同时,每日观察大鼠生殖器官发育状况。 2.采用苏木素-伊红染色法观察大鼠甲状腺、垂体、肝脏、肾上腺、睾丸、前列腺组织病理学变化。 3.采用酶联免疫吸附测定法(enzyme linked immunosorbent assay, ELISA)检测大鼠血清甲状腺激素T3、T4、TSH含量。 4.测定肝脏微粒体UDPGT活性观察DBDPE对甲状腺激素代谢相关酶活性的影响。 5.采用荧光定量PCR方法检测大鼠甲状腺和垂体相关基因表达。研究结果 1. DBDPE染毒后青春期雄性大鼠甲状腺、垂体、肝脏、肾上腺组织病理学与对照组相比没有发生明显改变。在300mg/kg和600mg/kg组,肝脏重量出现了显著性降低,其它脏器重量没有出现显著性改变；染毒期间及解剖当日染毒组大鼠体重随剂量增高有下降趋势,但没有出现统计学差异。 2.雄性大鼠经DBDPE染毒后,解剖当日,与对照组比较,甲状腺激素T4、T3水平在600mg/kg剂量组都出现显著性降低(p0.05),含量分别降低了10.3%和13.9%。同时,血清TSH含量在染毒组均出现显著性降低(p0.05),与对照组相比,100mg/kg剂量组TSH含量降低了43.1%,300mg/kg剂量组含量降低了49.3%,600mg/kg剂量组含量降低了35.0%。 3.测定了DBDPE染毒后肝脏微粒体代谢相关酶UDPGT活性,UDPGT活性在300mg/kg和600mg/kg剂量组出现显著性升高(p0.05),并且随着染毒剂量的增高各试验组UDPGT活性呈现出剂量-效应关系,在600mg/kg剂量组肝脏微粒体UDPGT活性最高。 4. DBDPE染毒后,甲状腺中Tpo(thyroid peroxidase, Tpo)mRNA表达在300mg/kg及600mg/kg剂量组中出现显著性增高,与对照组相比,分别相对增高了2.00倍及2.37倍；DBDPE染毒后,与对照组相比,Tg(thyroglobulin, Tg)mRNA表达在300mg/kg剂量组出现显著性增高,相对增高了1.8倍,在600mg/kg剂量组相对增高了1.6倍；Tshr (thyrotropin receptor, TSHR) mRNA表达在300mg/kg剂量组相对显著性上调了1.33倍；Dio2(iodothyronine deiodinase, Dio) mRNA表达在300mg/kg剂量组出现显著性增高,相比增高了1.72倍；Diol基因和Dio3基因与对照组相比,染毒组没有出现显著性差异；同时,染毒后Slc5a5(solute carrier family5, member5, Slc5a5) mRNA表达也没有出现显著性差异(p0.05)。垂体中,DBDPE染毒后Tshβ基因表达在各染毒组均出现显著性降低,与对照组相比,在100mg/kg、300mg/kg和600mg/kg组分别下调了1.17倍、1.15倍、1.07倍。在mRNA水平,100mg/kg组Dio2基因显著增高了1.46倍。Tra (thyroid hormone receptor α, Trα)、Trhr (TRH receptor, Trhr)、Dio1、 Dio3基因均未出现显著性差异(p0.05)。 5.观察DBDPE对雄性大鼠青春期发育的影响：结果表明,青春期雄性大鼠在染毒期间,包皮完全分离时间及完全分离时的体重,与对照组相比,各染毒组均无显著差异性(p0.05)。各染毒组大鼠双侧睾丸、前列腺、精囊重量与对照组比较也没有出现统计学改变。同时,染毒剂量至600mg/kg时大鼠睾丸、前列腺未见显著的组织病理学改变。研究结论 DBDPE可干扰青春期雄性大鼠甲状腺激素T3、T4、TSH在大鼠机体中的稳态,使青春期雄性大鼠血清T3、T4、TSH激素含量有所下降。其甲状腺毒性作用机制可能是通过影响肝脏微粒体激素代谢相关酶UDPGT使血清甲状腺激素T3、T4含量降低,体循环中甲状腺激素T3、T4含量的降低可引起甲状腺中特异性基因Tpo、Tg mRNA水平的增高,促使甲状腺自身合成更多的甲状腺激素T3、T4以补偿体循环中甲状腺激素的下降。DBDPE还可通过影响垂体中Dio2基因的表达,使垂体中的T4更多地转化为T3增多,在垂体局部,相对增多的T3负反馈引起Tsh mRNA水平下调,使垂体TSH分泌减少,从而导致体循环中TSH含量下降。此外,DBDPE对雄性大鼠的青春期发育影响不明显。
[Abstract]:Purpose of study

To investigate the effect of decabromodiphenyl ethane ( DBDPE ) on thyroid tissue of adolescent male rats after oral gavage , and determine the thyroid toxicity by measuring the contents of 3 , 5 , 3 ' triiodomethane ( T3 ) , 3 , 5 , 3 ' , 5 ' - tetraiodothyroxin ( TSH ) and thyroid stimulating hormone ( TSH ) .
To explore the mechanism of thyroid toxicity by measuring the activity of glucuronosyltransferase ( UDPGTs ) activity of liver microsomes after exposure to DBDPE and its effects on thyroid and pituitary - specific genes .
At the same time , the effects of DBDPE on the puberty development of male rats were studied to provide basic toxicological data for the comprehensive understanding of DBDPE endocrine disruption effect and safe use of DBDPE .

Research Methods

1 . The rats were randomly divided into two groups : control group , 100mg / kg group , 300 mg / kg group and 600mg / kg group .

2 . The pathological changes of the thyroid , pituitary , liver , adrenal gland , testis and prostate in rats were observed by the method of Su - lignin - eosin staining .

3 . Serum thyroid hormones T3 , T4 and TSH were measured by enzyme linked immunosorbent assay ( ELISA ) .

4 . The effect of DBDPE on the activity of thyroid hormone - related enzymes was observed by measuring the activity of UDPGT in liver microsomes .

5 . The expression of thyroid and pituitary - related genes in rats was detected by fluorescence quantitative PCR .

Results of the study

1 . The pathology of thyroid , pituitary , liver and adrenal gland of male rats after DBDPE had no significant change compared with control group . There was a significant decrease in liver weight in 300 mg / kg and 600 mg / kg group .
The body weight of the rats exposed to the virus during the exposure period and the anatomic day decreased with increasing dose , but there was no statistical difference .

2 . Compared with the control group , the levels of thyroid hormones T4 and T3 decreased by 10.3 % and 13.9 % in the dose group of 600 mg / kg , respectively , and the content of TSH in the dosage group decreased by 43.1 % and 49.3 % in the dosage group of 300 mg / kg , and the content of 600 mg / kg group was decreased by 33.0 % .

3 . The activity of UDPGT , UDPGT , UDPGT , UDPGT and UDPGT activity in liver microsomes were significantly increased after DBDPE exposure ( P < 0.05 ) , and the activity of UDPGT increased with the increase of the dosage of the dye . The activity of UDPGT in liver microsomes was the highest at the dosage of 600 mg / kg .

4 . After the DBDPE was poisoned , the mRNA expression of Tpo ( thyroid peroxidase , Tpo ) mRNA in thyroid was significantly higher in the dosage group of 300 mg / kg and 600 mg / kg , which was 2.00 times and 2.37 times higher than that in the control group , respectively .
Compared with the control group , the expression of Tg ( Tg ) mRNA increased significantly in the 300 mg / kg dose group compared with the control group , which was 1.8 times higher than that of the control group and 1.6 times higher in the 600 mg / kg group .
The mRNA expression of Tshr ( TSHR ) was up - regulated by 1.33 times in the 300 mg / kg dose group .
Dio mRNA expression was significantly higher in the 300 mg / kg dose group than that in the 300 mg / kg dose group , which was increased by 1 . 72 times .
Compared with the control group , the Diol gene and the Dio3 gene had no significant difference compared with the control group .
At the same time , there was no significant difference in mRNA expression of Slc5a5 ( P0.05 ) . In the pituitary , the expression of Tsh尾 gene was significantly decreased at 100 mg / kg , 300 mg / kg and 600 mg / kg in the pituitary . There was no significant difference in the mRNA level at 100 mg / kg , 300 mg / kg and 600 mg / kg , respectively .

5 . The effects of DBDPE on the puberty development of male rats were observed : the results showed that the total separation time and the weight of the male rats were not significantly different from the control group ( p < 0.05 ) .

Conclusions of the study

DBDPE can interfere with the steady state of thyroid hormones T3 , T4 and TSH in the rat body during puberty , and decrease the content of serum T3 , T4 and TSH in the rat body .
【学位授予单位】：广西医科大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R114

【参考文献】