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Reproductive toxicity and gender differences induced by cadmium telluride quantum dots in an invertebrate model organism

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ABSTRACT

Sexual glands are key sites affected by nanotoxicity, but there is no sensitive assay for measuring reproductive toxicity in animals. The aim of this study was to investigate the toxic effects of cadmium telluride quantum dots (CdTe-QDs) on gonads in a model organism, Bombyx mori. After dorsal vein injection of 0.32 nmol of CdTe-QDs per individual, the QDs passed through the outer membranes of gonads via the generation of ROS in the membranes of spermatocysts and ovarioles, as well as internal germ cells, thereby inducing early germ cell death or malformations via complex mechanisms related to apoptosis and autophagy through mitochondrial and lysosomal pathways. Histological observations of the gonads and quantitative analyses of germ cell development showed that the reproductive toxicity was characterized by obvious male sensitivity. Exposure to QDs in the early stage of males had severe adverse effects on the quantity and quality of sperm, which was the main reason for the occurrence of unfertilized eggs. Ala- or Gly-conjugated QDs could reduce the nanotoxicity of CdTe-QDs during germ cell development and fertilization of their offspring. The results demonstrate that males are preferable models for evaluating the reproductive toxicity of QDs in combined in vivo/in vitro investigations.

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Spermateleosis was affected by the duration of exposure to QDs in vivo and the duration of culture free from QDs in vitro.(A) Ratio of spermatodesms relative to the total number of spermatocysts. (B) Ratio of damaged spermatocysts relative to the total number of spermatocysts. Fifth instar larvae received vascular injection of 0.32 nmol CdTe QDs, QDs-Ala, or QDs-Gly per larva (10 μL at 32 μM per individual) at 48 h after molting, whereas the control organisms (CK) were injected with the same volume of pure water. Spermatocysts were removed from male larvae at 12 h, 24 h, or 72 h after exposure to QDs and then cultured in vitro without QDs. The duration of exposure in vivo was the time until the removal of testes after exposure to QDs. Samples marked with the same letter do not differ significantly from each other, P < 0.05 (n = 3 microscopic fields of view).
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f5: Spermateleosis was affected by the duration of exposure to QDs in vivo and the duration of culture free from QDs in vitro.(A) Ratio of spermatodesms relative to the total number of spermatocysts. (B) Ratio of damaged spermatocysts relative to the total number of spermatocysts. Fifth instar larvae received vascular injection of 0.32 nmol CdTe QDs, QDs-Ala, or QDs-Gly per larva (10 μL at 32 μM per individual) at 48 h after molting, whereas the control organisms (CK) were injected with the same volume of pure water. Spermatocysts were removed from male larvae at 12 h, 24 h, or 72 h after exposure to QDs and then cultured in vitro without QDs. The duration of exposure in vivo was the time until the removal of testes after exposure to QDs. Samples marked with the same letter do not differ significantly from each other, P < 0.05 (n = 3 microscopic fields of view).

Mentions: Figure 5A shows the changes in the ratio of spermatodesms relative to the total number of spermatocysts when the testes were removed at 12 h, 24 h, or 72 h after exposure to QDs and then cultured in vitro. In the control group, the ratio increased significantly with the time of in vitro culture, where the ratio of spermatodesms relative to the total number of spermatocysts was 1.64 times higher at 168 h when the testes were removed at 24 h and the spermatocysts were cultivated in vitro compared with that when the testes were removed at 12 h (Fig. 5A). The ratio of damaged spermatocysts was also 58% lower when the testes were removed at 24 h compared with that when they were removed at 12 h (Fig. 5B).


Reproductive toxicity and gender differences induced by cadmium telluride quantum dots in an invertebrate model organism
Spermateleosis was affected by the duration of exposure to QDs in vivo and the duration of culture free from QDs in vitro.(A) Ratio of spermatodesms relative to the total number of spermatocysts. (B) Ratio of damaged spermatocysts relative to the total number of spermatocysts. Fifth instar larvae received vascular injection of 0.32 nmol CdTe QDs, QDs-Ala, or QDs-Gly per larva (10 μL at 32 μM per individual) at 48 h after molting, whereas the control organisms (CK) were injected with the same volume of pure water. Spermatocysts were removed from male larvae at 12 h, 24 h, or 72 h after exposure to QDs and then cultured in vitro without QDs. The duration of exposure in vivo was the time until the removal of testes after exposure to QDs. Samples marked with the same letter do not differ significantly from each other, P < 0.05 (n = 3 microscopic fields of view).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037452&req=5

f5: Spermateleosis was affected by the duration of exposure to QDs in vivo and the duration of culture free from QDs in vitro.(A) Ratio of spermatodesms relative to the total number of spermatocysts. (B) Ratio of damaged spermatocysts relative to the total number of spermatocysts. Fifth instar larvae received vascular injection of 0.32 nmol CdTe QDs, QDs-Ala, or QDs-Gly per larva (10 μL at 32 μM per individual) at 48 h after molting, whereas the control organisms (CK) were injected with the same volume of pure water. Spermatocysts were removed from male larvae at 12 h, 24 h, or 72 h after exposure to QDs and then cultured in vitro without QDs. The duration of exposure in vivo was the time until the removal of testes after exposure to QDs. Samples marked with the same letter do not differ significantly from each other, P < 0.05 (n = 3 microscopic fields of view).
Mentions: Figure 5A shows the changes in the ratio of spermatodesms relative to the total number of spermatocysts when the testes were removed at 12 h, 24 h, or 72 h after exposure to QDs and then cultured in vitro. In the control group, the ratio increased significantly with the time of in vitro culture, where the ratio of spermatodesms relative to the total number of spermatocysts was 1.64 times higher at 168 h when the testes were removed at 24 h and the spermatocysts were cultivated in vitro compared with that when the testes were removed at 12 h (Fig. 5A). The ratio of damaged spermatocysts was also 58% lower when the testes were removed at 24 h compared with that when they were removed at 12 h (Fig. 5B).

View Article: PubMed Central - PubMed

ABSTRACT

Sexual glands are key sites affected by nanotoxicity, but there is no sensitive assay for measuring reproductive toxicity in animals. The aim of this study was to investigate the toxic effects of cadmium telluride quantum dots (CdTe-QDs) on gonads in a model organism, Bombyx mori. After dorsal vein injection of 0.32&thinsp;nmol of CdTe-QDs per individual, the QDs passed through the outer membranes of gonads via the generation of ROS in the membranes of spermatocysts and ovarioles, as well as internal germ cells, thereby inducing early germ cell death or malformations via complex mechanisms related to apoptosis and autophagy through mitochondrial and lysosomal pathways. Histological observations of the gonads and quantitative analyses of germ cell development showed that the reproductive toxicity was characterized by obvious male sensitivity. Exposure to QDs in the early stage of males had severe adverse effects on the quantity and quality of sperm, which was the main reason for the occurrence of unfertilized eggs. Ala- or Gly-conjugated QDs could reduce the nanotoxicity of CdTe-QDs during germ cell development and fertilization of their offspring. The results demonstrate that males are preferable models for evaluating the reproductive toxicity of QDs in combined in vivo/in vitro investigations.

No MeSH data available.


Related in: MedlinePlus