다환방향족 탄화수소, benzo[a]pyrene노출이 두줄망둑, Tridentiger trigonocephalus의 생식 특성에 미치는 영향

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants derived from incomplete combustion of carbon and crude oil. PAHs are typically associated with toxicity, however, newer evidence suggests that these compounds may also act as endocrine system disruptors. In the present study, the effect of benzo[a]pyrene (B[a]P), a representative carcinogenic PAHs was investigated through histological, physiological, and molecular biological indicators using in vitro and in vivo assay from marine fish species, Tridentiger trigonocephalus. The overall objectives of the present study were 1) to investigate reproductive characteristics of chameleon goby, Tridentiger trigonocephalus, 2) to determine if in vitro exposure to B[a]P affected germinal vesicle break down (GVBD) and sex steroid hormone production from maturing oocytes of T. trigonocephalus and 3) to determine if waterborne exposure to B[a]P affected steroid hormone production in ovary and transcription of cytochrom P450 1A1 (CYP1A1), estrogen receptor β1 (ERβ1) and membrane progestin receptor α (mPRα). The first objective of this study was to characterize the reproductive cycle of chameleon goby, T. trigonocephalus. Gonadal development was investigated using a histological method. Specimens were collected monthly from April 2009 to March 2010, in the South Sea of Korea. The gonadosomatic index (GSI) of females began to increase in April, reached a maximum in May, and declined sharply in August. In males, the GSI began to increase in April and reached a maximum in July. The annual reproductive cycle of T. trigonocephalus can be divided into four successive stages in females: the growing (November-March), maturing (April-May), ripe and spawning (June-July), and recovery (August-October) stages. Males passed through growing (November-March), maturing (April-June), ripe and spermiation (July-August), and recovery (September-October) stages. These results indicate that the spawning season was from June to July. The relationship between fecundity () and body length (BL) was . Fecundity ranged from 3,448-9,654 eggs in a total length of 4.8-7.2 cm and increased with total length. In the 2nd experiment, maturing oocytes from T. trigonocephalus were exposed to in vitro B[a]P (0, 0.1, 1, 10, 100 and 1,000 nM) for 24 hrs. In vitro exposure to B[a]P induced GVBD significantly at lower concentrations and stimulated E2 production at higher concentrations. However, the effecs of B[a]P on the production of 17,20β-dihydroxy-4-pregnen-3-one (17α20βP) were increased or decreased at different tested-dose with controversy to concentrations of E2. In the last experiment, matured T. trigonocephalus were exposed waterborne B[a]P (0, 10 and 20 ㎍/L) for 30 days. Waterborne B[a]P decreased E2 and 17α20βP production from ovary. Moreover, B[a]P decreased the ratio of E2/T. In the transcription of target genes, B[a]P increased CYP1A1 mRNA and decreased ERβ1 mRNA in liver. There are not any significant effects on mPRα mRNA. The results from this study suggested that reproduction in chameleon goby is affected by exposure to B[a]P and that increase in transcription of CYP1A1, decrease in E2 production and transcription ERβ1 may be one mechanism of B[a]P-induced reproductive endocrine disruption.