17α-甲基睾酮对稀有鮈鲫肝脏脂质代谢的影响

Effects of 17α-methyltestosterone on Lipid Metabolism in Liver of Gobiocypris rarus

环境内分泌干扰物对环境影响十分严重,绝大部分进入水环境,危害水生生物健康,进而影响人类健康。17α-甲基睾酮(17α-methyltestosterone,MT)是一种常见的环境雄激素,但在鱼体内的作用机制尚不明确。为了探究MT对鱼类肝脏脂质代谢的影响,采用不同浓度的MT(0、25、50和100 ng·L^(-1))处理864尾稀有鮈鲫(Gobiocypris rarus),分别在7、14和21 d取肝脏样品。用石蜡组织切片(H-E染色)研究MT对稀有鮈鲫肝脏组织的影响;用RT-qPCR检测4个内参基因的稳定性及5个脂质代谢相关基因(acaca、acacb、fasn、gpat1和cpt1α)的mRNA表达;用ELISA法测定肝脏中甘油三酯的含量。结果表明,MT会对稀有鮈鲫肝脏造成一定程度的影响,50 ng·L^(-1)MT处理14 d,肝脏组织损伤最明显。25 ng·L^(-1)和50 ng·L^(-1)MT处理14 d,相关基因的表达均显著变化(P<0.05)。mRNA表达与组织学结果均表明50 ng·L^(-1)MT对稀有鮈鲫肝脏影响最为显著。100 ng·L^(-1)MT处理21 d,acaca、cpt1α和gpat1基因表达量显著下降(P<0.05)。MT对雌鱼肝脏甘油三酯影响较雄鱼大。综上,MT通过影响肝脏脂质代谢相关基因mRNA的表达,干扰了稀有鮈鲫肝脏脂质代谢过程,进而对肝脏产生不同程度的损伤。由于MT在不同性别鱼体内的代谢途径不同,推测MT在稀有鮈鲫体内可能被芳香化为雌激素(ME),从而发挥部分雌激素作用。

Environmental endocrine disrupting chemicals have serious impacts on the environment.Most of these chemicals eventually enter the water environment,endangering the health of aquatic organisms and then affecting human health.The 17α-methyltestosterone(MT)is a common environmental androgen,but its action mechanism in fish is still unclear.To explore the effect of MT on the lipid metabolism in fish,different concentrations of MT(0,25,50 and 100 ng·L^(-1))were used to treat 864 Gobiocypris rarus,and liver samples were taken on 7,14 and 21 d,respectively.The tissue paraffin slice(H-E staining)was used to study the effect of MT on the liver tissues.RT-qPCR was used to detect the stability of four reference genes and the mRNA expressions of five lipid metabolism-related genes(acaca,acacb,fasn,gpat1 and cpt1α).The content of triglycerides in the liver was detected by ELISA.The results showed that MT impacted on the liver of G.rarus to a certain extent,with obvious damage at 50 ng·L^(-1) MT for 14 d.The gene expressions were changed significantly after treatment with MT at both 25 ng·L^(-1)and 50 ng·L^(-1) for 14 d(P<0.05).Both mRNA expressions and histological results showed that 50 ng·L^(-1) MT had the most significant effect on the liver.The expressions of acaca,cpt1αand gpat1 decreased significantly(P<0.05)after treating with 100 ng·L^(-1) MT for 21 d.The effect of MT on the triglyceride deposits in the liver of females is greater than that of males.In conclusion,MT interferes with the liver lipid metabolism of G.rarus by affecting the expression of corresponding genes,and then causes some damages to the liver.Based on the different metabolic pathways of MT in both sexes,we speculate that MT may be aromatized into estrogen in G.rarus,thus exerting part of the estrogen effects.