试验253：使用大型蚤（JHASA）进行短期幼年激素活性筛查试验

Test Guideline No. 253Short-term Juvenile Hormone ActivityScreening Assay usingDaphniamagna(JHASA) 25 June 2024OECD Guidelines for the Testingof Chemicals OECD/OCDEYou are free to use this material subject to the terms and conditions available athttp://www.oecd.org/termsandconditions/1OECD GUIDELINE FOR THE TESTING OF CHEMICALSNote: As of15January 2025, the title of Test Guideline No. 253, "Test No. 253: Short-term juvenilehormone (JH) activity screening assay inDaphnia magna" has been updated to "Test No. 253:Short-term Juvenile Hormone Activity Screening Assay usingDaphnia magna(JHASA)".Short-term Juvenile Hormone Activity Screening Assay usingDaphnia magna(JHASA)1.This Test Guideline (TG) describes a short-term juvenile hormone (JH) activity screeningassay usingDaphnia magnato detect the potential of chemicals with JH activity.TheJHASA was designed as a screen assay which evaluates male offspring production in theparthenogenetic daphnid, as described in Annex 7 of OECD TG 211 (Daphnia magnaReproduction Test). The JHASA is placed at level 3 of the OECD Conceptual Frameworkfor the testing of endocrine disrupting chemicals (EDCs) in Guidance Document 150 (1) formechanistic information and is not intended to determine toxicity values (i.e. no observedeffectconcentration[NOEC]or Effect concentration for x%effect[ECx])for riskassessment, unless there is a concentration response curve based on more than three2.The concept of the JHASA is based on the studies of male offspring production in theparthenogenetic daphnids, which is regulated by JH signaling pathway (2, 3). Productionof male offspring is usually known to occur under environmental stimuli, such as shorteningofphotoperiod,lowering temperature,decreasing quantity of food,and increasingpopulation density (4-6). However, male offspring production is also induced by theexposure to innate JHs of crustaceans and insects (methyl farnesoate for crustacean andJH I, II, III for insects) and JH analogs (JHAs)such as insect growth regulators (e.g.hydroprene, pyriproxyfen, fenoxycarb) (7-10) and could lead to population-relevant effects(11). To use this male offspring production as an additional mean of detecting chemicalswith JH activity, inter-laboratory validation study was conducted (12) and evaluation of maleoffspring production was added to Annex 7 of TG 211Daphnia magnaReproduction Testas an optional measurement endpoint in 2008 (13).3.TG 211 Annex 7 can provide sufficient data for hazard and risk assessment; however, thistest requires additional resources and cost to identify sex of all offspring produced for 21days. Thus, the Short-term Juvenile Hormone Activity Screening Assay usingDaphniamagna(JHASA), was developed to shorten the test period from 21 days in TG211 Annex7to approximately 7 days in JHASA(14-16).Based on the knowledge that sexdetermination of offspring occurs during the critical period of oocyst development in ovary,approximately 7-10 h before ovulation to the brood chamber (17), JHASA starts exposurefrom mature adult females (e.g. 10-17 days old) and only observes offspring from the ©OECD, (2024)INTRODUCTIONtreatment levels. OECD/OCDE2second brood after the exposure. The first brood in the brood chamber at the start of thetest is not included in the observation because its sex has been already determined prior4.The mature females(parent animal) with developing embryos in their brood chambers areexposed toat leastthree concentrations of test chemicalanda water control(and a solventcontrol if necessary). The test duration is approximately 7 days, until the test daphnidsreproduce the second brood after the exposure. Test duration may be extended until allsurviving daphnids produce the second brood (see section “Duration” for more detail). Tenvessels or replicates (each vessel containing 1 mature female) are used for each treatment.Thenumber of female and male offspring of the second brood is counted. Identification ofoffspring sex is performed by macroscopic observation of the first antenna, which is longerin males than in females. Mortality of parent animals is also recorded. The proportion ofmale offspring (male ratio) is calculated in each of treatment replicates when the secondbrood is produced. The summary of the test parameters and conditions can be found in5.The JHASA serves as a screen for chemicals having JH-like activity which can be detectedby production of male offspring in the test concentrations. If no male offspring is observedin control(s), the test chemical having male offspring induction may be considered ‘active’without statistical analysis. However, if a few males are found in control(s) or if only a fewmales are induced in the exposures, male ratio should be analyzed to determine statisticallysignificant differences between the exposures andcontrol(s) response (see Annex 6 formore details). In addition,ifthe possibility that males are induced by other environmentalfactors (e.g. feeding, density, photoperiod, temperatur