Reproductive impacts of tributyltin (TBT) and triphenyltin (TPT) in the hermaphroditic freshwater gastropod Lymnaea stagnalis

in Environmental Toxicology and Chemistry (in press), 2013

Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment ... [more ▼]

Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed at comparing the relative toxicity of TBT and TPT under similar laboratory conditions in the 0–600 ng Sn/L range. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length and reproduction were monitored in a 21d semi-static test. Frequency of abnormal eggs was assessed as an additional endpoint. TPT hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, since snail responses to TBT could be detected at concentrations as low as 19 ng Sn/L. However, the putative mode of action of the two compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared to the sensitivity of prosobranch molluscs with different habitats and different reproductive strategies. [less ▲]

Reproductive impact and proteomic analysis of androgenic and anti-androgenic disruptors on the hermaphroditic freshwater gastropod Lymnaea stagnalis

Poster (2011, November)

In this study, e ects of two androgens (tributyltin and testosterone), one antiandrogen (cyproterone acetate) and one estrogen (chlordecone) on growth and reproduction were investigated in the ... [more ▼]

In this study, e ects of two androgens (tributyltin and testosterone), one antiandrogen (cyproterone acetate) and one estrogen (chlordecone) on growth and reproduction were investigated in the hermaphrodite gastropod Lymnaea stagnalis. In this study, exposure to a range of concentrations (ng/l to μg/l) of each chemical was performed during 21 days. e number of clutches and the number of eggs per clutch were monitored. A decrease in clutches laid per snail was observed after exposure to tributyltin (540, 1180 and 2600 ng/l) and chlordecone (10, 22, 50 and 110 μg/l). A signi cant decrease in egg laid per snail was observed after exposure to tributyltin (540, 1180 and 2600 ng/l) and chlordecone (50 and 110 μg/l). An increase of egg abnormalities ratio in exposed snails (atrophied albumen, polyembryonicity,...) was observed in L. stagnalis following exposure to testosterone (2, 22, 50 and 110 ng/l), cyproterone acetate (4,5 and 50 μg/l), tributyltin (110 and 244 ng/l) and chlordecone (4,5 and 10 μg/l). Investigation of alteration in protein expression in exposed snails was performed using proteomic analysis such as 2D-DIGE. Mass spectrometry identi cation was performed on proteins with altered expression. We could establish correlation between reproductive endpoints and changes in proteins involved in egg formation and in egg laying were underlined. Egg yolk ferritin, the main protein of egg yolk, was shown to be reduced signi cantly in relationship with a decrease of egg yolk quality after exposure to tributyltin 540 ng/l and cyproterone acetate 4,5 μg/l. Ovipostatin, a protein proved to reduce egg masses, was signi cantly over expressed in snails exposed to 50 μg/l of chlordecone and were in relationship with a reduction of clutches laid by individuals. Further western blot analysis on those proteins involved in the reproduction are underway. ese analysis will enable us to con rm and re ne with more speci city the 2D-DIGE results for the selected proteins. e results of this study can help to establish new biomarkers of exposure of endocrine disruptors in freshwater environment and can provide new insight on mode of action of endocrine disruptors in L. stagnalis. [less ▲]