Perturbation of Organogenesis by the Herbicide Atrazine in the AmphibianXenopus laevis

Abstract

BackgroundExposure to anthropogenic chemicals during development can disrupt the morphogenesis of organ systems. Use of the herbicide atrazine has been debated in recent years because of its implicated, but poorly characterized, effects on vertebrates. Previous studies primarily examined the effects of atrazine exposure during metamorphosis or early developmental stages of amphibians.ObjectivesWe sought to identify and characterize the susceptibility during the often-overlooked developmental stage of organ morphogenesis.MethodsWe used a static renewal experimental treatment to investigate the effects of 10, 25, and 35 mg/L atrazine from early organ morphogenesis through the onset of tadpole feeding in the aquatic amphibian model system, Xenopus laevis. We quantified malformations of the body axis, heart, and intestine, as well as apoptosis in the midbrain and pronephric kidney.ResultsWe found a significant dose-dependent increase in the percentage of atrazine-exposed tadpoles with malformations of multiple tissues including the main body axis, circulatory system, kidney, and digestive system. Incidence of apoptotic cells also increased in the both midbrain and kidney of atrazine-exposed tadpoles.ConclusionsOur results demonstrate that acute atrazine exposure (10–35 mg/L for ≤ 48 hr) during early organ morphogenesis disrupts proper organ development in an amphibian model system. The concurrent atrazine-induced apoptosis in the pronephric kidney and midbrain begins to elucidate a mechanism by which atrazine may disrupt developmental processes in nontarget organisms.

Acute atrazine exposure disrupts matrix metalloproteinases and retinoid signaling during organ morphogenesis in Xenopus laevis

“…Even after tadpoles of four different amphibian species begin feeding, there is a differential response to low atrazine concentrations such that early or late larval stages appear to be more sensitive to atrazine exposure depending on the species (Storrs and Kiesecker, 2004). Previously, we also showed that acute atrazine exposure just prior to the onset of feeding disrupts proper development of the anterior-posterior axis, heart, intestines, kidney and midbrain of X. laevis tadpoles (Lenkowski et al, 2008). Interestingly, other vertebrates examined have shown increased sensitivity to atrazine during organ morphogenesis, suggesting it may be a particularly sensitive developmental stage across vertebrates.…”

“…Adult Xenopus laevis (Nasco, Fort Atkinson, WI, USA) were housed and eggs were collected as previously described (Lenkowski et al, 2008). Embryos were reared in 0.1¥ Marc's modified Ringer's solution (MMR; 0.01 M NaCl, 0.2 mM KCl, 0.1 mM MgCl2, 0.2 mM CaCl2, 0.5 mM HEPES; pH 7.5, Fisher Scientific).…”

“…However, edemas and malformations of the head, intestine, and axis also occur at lower doses (e.g. 10 mg l -1 ; Lenkowski et al, 2008), and disruption of cartilage and muscle …”

“…The effects of atrazine have been studied during early (Morgan et al, 1996), intermediate (Lenkowski et al, 2008;Morgan et al, 1996) and late (Coady et al, 2005;Hayes et al, 2003) stages of amphibian development, yet molecular mechanisms for malformations observed during tadpole stages have not been described. We have therefore characterized tissue-and molecular-level effects of atrazine exposure during organ morphogenesis in X. laevis to identify pathways by which acute atrazine exposure may affect developmental processes.…”

Studying of effect of atrazine and its Negative Effect on Reproductive Organs of Pregnant White Mice Musmusculus and Their Off spring

“…‫البرمائيات‬ ‫ودعاميص‬ ‫الجنة‬ ‫التطورية‬ ( 1 ) ‫تشوه‬ ‫يسبب‬ ‫لالترازين‬ ‫البرمائيات‬ ‫اجنة‬ ‫تعرض‬ ‫بان‬ ‫الدراسات‬ ‫احدى‬ ‫اشارت‬ ‫اذ‬ ‫الهضمية‬ ‫االنظمة‬ ‫في‬ ‫وخلل‬ ‫كلوي‬ ‫وضعف‬ ‫قلبي‬ ( 2 ) ‫للقلب‬ ‫البطيني‬ ‫االذيني‬ ‫الصمام‬ ‫تشوه‬ ‫الى‬ ‫ادى‬ ‫اخرى‬ ‫دراسات‬ ‫وفي‬ ( 3 ) ‫كما‬ ‫التفافها‬ ‫وعكس‬ ‫االمعاء‬ ‫طول‬ ‫زيادة‬ ‫الى‬ ‫ادى‬ ( 4 ) ‫الدعاميص‬ ‫ذيول‬ ‫تقوس‬ ‫ويسبب‬ ( 5 ) . ‫به‬ ‫الملوثة‬ ‫المياه‬ ‫شرب‬ ‫عند‬ ‫الرضع‬ ‫االطفال‬ ‫اوزان‬ ‫انخفاض‬ ‫الى‬ ‫يؤدي‬ ‫كما‬ ( 6 ) ‫مما‬ ‫التعظم‬ ‫في‬ ‫نقص‬ ‫العالية‬ ‫الجرعات‬ ‫وتسبب‬ ‫االرانب‬ ‫اجنة‬ ‫في‬ ‫الوزن‬ ‫نقص‬ ‫يسبب‬ ( 7 ) ‫وتاخر‬ ‫ناضجة‬ ‫وغير‬ ‫الوزن‬ ‫منخفضة‬ ‫اجنة‬ ‫والدة‬ ‫في‬ ‫المبيد‬ ‫تاثير‬ ‫اكدت‬ ‫اخرى‬ ‫ودراسة‬ ‫عيو‬ ‫عن‬ ‫فضال‬ ‫الجنسي‬ ‫والنضج‬ ‫العظام‬ ‫تطور‬ ‫به‬ ‫الشرب‬ ‫مياه‬ ‫تلوث‬ ‫عند‬ ‫والدية‬ ‫ب‬ ( 8 ) ‫االجنة‬ ‫اجهاض‬ ‫حاالت‬ ‫من‬ ‫ويزيد‬ ( 9 ) ‫المشيمة‬ ‫على‬ ‫تاثيره‬ ‫خالل‬ ‫من‬ ‫لالجنة‬ ‫منخفضة‬ ‫بقاء‬ ‫نسبة‬ ‫ويسبب‬ ( 10 ) ‫االناث‬ ‫في‬ ‫حيضية‬ ‫مشاكل‬ ‫الى‬ ‫ويؤدي‬ ( 11 ) ‫ايضا‬ ‫ويسبب‬ ‫الرحم‬ ‫جدار‬ ‫سمك‬ ‫في‬ ‫زيادة‬ ( 12 ) ‫الجني‬ ‫للتطور‬ ‫االولى‬ ‫المراحل‬ ‫في‬ ‫الجرذان‬ ‫اجنة‬ ‫وتعرض‬ ‫في‬ ‫الثديية‬ ‫الغدد‬ ‫نمو‬ ‫تاخر‬ ‫يسبب‬ ‫ني‬ ‫االناث‬ ( 13 ) ‫االستروجين‬ ‫هرمون‬ ‫مستوى‬ ‫وزيادة‬ ( 14 ) ‫للحيامن‬ ‫الحركية‬ ‫القدرة‬ ‫ويخفض‬ ( 15 ) ‫الحيامن‬ ‫عدد‬ ‫انخفاض‬ ‫يسبب‬ ‫كما‬ ‫الذكور‬ ‫في‬ ( 16 ) ‫الذكور‬ ‫في‬ ‫المناعية‬ ‫االستجابة‬ ‫ويثبط‬ ( 17 ) ‫الوراثي‬ ‫والضرر‬ ‫لالترازين‬ ‫التعرض‬ ‫ارتباط‬ ‫اخرى‬ ‫دراسة‬ ‫وبينت‬ ‫الكروموسومات‬ ‫تلف‬ ‫زيادة‬ ‫الى‬ ‫يؤدي‬ ‫كما‬ ‫الفقريات‬ ‫في‬ ( 18 ) .…”