Chlorpyrifos exposure reduces reproductive capacity owing to a damaging effect on gametogenesis in the nematode Caenorhabditis elegans

Abstract

Previous studies have revealed that chlorpyrifos exposure adversely affects the reproductive capacity of male rodents. The present study investigated the reproductive toxicity of chlorpyrifos exposure and possible related mechanisms using the nematode Caenorhabditis elegans. L4 nematode larvae were exposed to chlorpyrifos at concentrations of 0.003, 0.03, 0.3 and 3.0 mg l(-1) for different durations. In addition to decreased brood size, reduced spermatid size, increased percentage of abnormal spermatids, suppressed spermatid activation and motility of sperm, damaged oocyte morphology, increased numbers of apoptotic cells and unfertilized oocytes were observed in nematodes exposed to various concentrations of chlorpyrifos. Moreover, expression patterns of the genes spe-10, spe-15, fer-1, prg-1, glp-1, mlh-1, cyb-3, ced-3, ced-4 and ced-9 (which are associated with spermatid size, spermatid activation and morphology, oocyte morphology, oocyte function, and apoptosis) were altered after chlorpyrifos exposure. Therefore, chlorpyrifos exposure may adversely affect fertility in nematodes by influencing both spermatogenesis and oogenesis. Alterations in the expression patterns of genes involved in gametogenesis may explain the corresponding changes in gametogenesis in nematodes exposed to chlorpyrifos. Hence, the model organism Caenorhabditis elegans is recommended for assessment of reproductive toxicity relating to gametogenesis.

ZnO nanoparticles enhanced germ cell apoptosis in Caenorhabditis elegans , in comparison with ZnCl 2

“…Environmental stress can cause a significant increase in apoptosis beyond the normal range for producing nurse cells. Excess apoptosis can reduce the number of mature oocytes and thus reduce the number of offspring (Polli et al, 2014;Ruan et al, 2012). This study investigated effects of ZnO NPs exposure on C. elegans germ cell apoptosis and related gene expressions, proposed as a potential mechanism of observed reproductive inhibition reported by previous studies.…”

The Use of the Nematode Caenorhabditis elegans to Evaluate the Adverse Effects of Epoxiconazole Exposure on Spermatogenesis

“…The number of outcross progeny was counted as previous described [25]. him-5 mutants were exposed to epoxiconazole for 48 h, then crossed with a young adult fog-2 female for 12 h. Nematodes were transferred daily to new agar plates until the females ceased egg-laying.…”

“…The sperm size was measured and analyzed as previously published [25]. After exposure to epoxiconazole for 48 h, him-5 was placed in a drop of SM (Sperm Medium) solution (50 mM of Hepes, 1 mM of MgSO 4 , 25 mM of KCl, 45 mM of NaCl and 5 mM of CaCl 2 at pH 7.0) and then dissected to release spermatids.…”

“…The final performed volume of RNA reverse transcription was 25 μL containing 5 μL of the moloney murine leuke virus (MMLV) reaction buffer, 1.25 μL of 4× dNTPs, 0.65 μL of RNase inhibitor, and 1 μL of MMLV (Promega, Madison, WI, USA). The cDNA was synthesized for 60 min at 45 °C and heated for 5 min to 95 °C [25]. …”

“…act-1 , consistently expressed at all stages in C. elegans [23] and which exhibited relatively stable expression as a reference gene when exposed to chlorpyrifos in our previous paper [25], was used as an internal control gene to normalize individual samples [35]. The presence of primer dimers and nonspecific PCR products were evaluated via dissociation curve analysis.…”