71
potential embryo-toxic agents for a period of 10 days and observed the spontaneous
differentiation into beating cardiomyocytes. However, the method was subsequently
modified in different laboratories, changing the endpoint or selecting more mature
stem cells, such as mesenchymal or endothelial. Recent reviews on this matter are
available (Brannen et al. 2016; Das et al. 2016; Handral et al. 2016). Table 3.2
summarizes several recommended protocols. The most important characteristics,
and the results in nanotoxicity, are discussed in next subsections.
3.5.1 Culture of Early Mammal Embryo
The early zygote of mammals, obtained by artificial fertilization of a mature egg,
can evolve outside the maternal body until the blastocyst stage, that is, the
preimplantation period, ending with the “hatching” of the animal pole from the
pellucida zone. The early zygote development proceeds from the fecundated egg
into the two-cell stage, the morula and the blastocyst, where the polarity of the
zygote is established between the animal pole, where the embryo and the future
placenta will develop, and the opposite pole, evolving into extra-embryonic
membranes. The overall viability, the blastocyst rate, and cell number are the
endpoints most frequently studied. The hatching rate, the cavitation rate, the
expression of markers of maturation, such as trophectoderm-associated genes, or of
oxidative stress and apoptosis markers are other indicators of safety/toxicity. If
transferred in vivo, in optimal conditions, the blastocyst starts implantation and
generates a new individual: this is the endpoint of the methods for artificial
reproduction. Low implantation and high resorption rate, or poor vitality and
performance of newborns, give a measure of risk hazard in toxicology.
Several studies tested the effects of different types of nanoparticles in this model.
Polystyrene was safer than polyacrylonitrile, and both inhibited the hatching of
mouse blastocyst (Fynewever et al. 2007). Instead, the organic nanoparticles of
polylactic-co-glycolic acid seems to be safe to the in vitro developing mouse
embryo. The early embryo accumulated labeled nanoparticles, which persisted in
all preimplantation stages. Moreover, after the transfer in a healthy female, the
development proceeded normally until the delivery of healthy offspring (Kim
et al. 2018).
The Quantum Dots induced apoptosis and reduced the cell number in the blastocysts (Chan and Shiao 2008; Hsieh et al. 2009), as did silver nanoparticles, that
reduced the successful implantation and development when embryos were transferred into the uterus (Li et al. 2010). Chitosan nanoparticles were toxic for exposed
morula, while nanocapsules with a lipid core, loaded with antioxidant agents, such
as tretinoin and melatonin, had positive effects on the development of bovine blastocysts after artificial fertilization (Gomes Lucas et al. 2015; Komninou et al. 2016;
Remião et al. 2016). Golden nanoparticles were instead safe, according to Taylor
et al. (2014). These evidences assume a special relevance in the perspective of possible exploitations of nanotechnology to improve the success and performance of
artificial fecundation techniques.
3 Safety and Utility of Nanomaterials on Reproduction and Development: An Update…
potential embryo-toxic agents for a period of 10 days and observed the spontaneous
differentiation into beating cardiomyocytes. However, the method was subsequently
modified in different laboratories, changing the endpoint or selecting more mature
stem cells, such as mesenchymal or endothelial. Recent reviews on this matter are
available (Brannen et al. 2016; Das et al. 2016; Handral et al. 2016). Table 3.2
summarizes several recommended protocols. The most important characteristics,
and the results in nanotoxicity, are discussed in next subsections.
3.5.1 Culture of Early Mammal Embryo
The early zygote of mammals, obtained by artificial fertilization of a mature egg,
can evolve outside the maternal body until the blastocyst stage, that is, the
preimplantation period, ending with the “hatching” of the animal pole from the
pellucida zone. The early zygote development proceeds from the fecundated egg
into the two-cell stage, the morula and the blastocyst, where the polarity of the
zygote is established between the animal pole, where the embryo and the future
placenta will develop, and the opposite pole, evolving into extra-embryonic
membranes. The overall viability, the blastocyst rate, and cell number are the
endpoints most frequently studied. The hatching rate, the cavitation rate, the
expression of markers of maturation, such as trophectoderm-associated genes, or of
oxidative stress and apoptosis markers are other indicators of safety/toxicity. If
transferred in vivo, in optimal conditions, the blastocyst starts implantation and
generates a new individual: this is the endpoint of the methods for artificial
reproduction. Low implantation and high resorption rate, or poor vitality and
performance of newborns, give a measure of risk hazard in toxicology.
Several studies tested the effects of different types of nanoparticles in this model.
Polystyrene was safer than polyacrylonitrile, and both inhibited the hatching of
mouse blastocyst (Fynewever et al. 2007). Instead, the organic nanoparticles of
polylactic-co-glycolic acid seems to be safe to the in vitro developing mouse
embryo. The early embryo accumulated labeled nanoparticles, which persisted in
all preimplantation stages. Moreover, after the transfer in a healthy female, the
development proceeded normally until the delivery of healthy offspring (Kim
et al. 2018).
The Quantum Dots induced apoptosis and reduced the cell number in the blastocysts (Chan and Shiao 2008; Hsieh et al. 2009), as did silver nanoparticles, that
reduced the successful implantation and development when embryos were transferred into the uterus (Li et al. 2010). Chitosan nanoparticles were toxic for exposed
morula, while nanocapsules with a lipid core, loaded with antioxidant agents, such
as tretinoin and melatonin, had positive effects on the development of bovine blastocysts after artificial fertilization (Gomes Lucas et al. 2015; Komninou et al. 2016;
Remião et al. 2016). Golden nanoparticles were instead safe, according to Taylor
et al. (2014). These evidences assume a special relevance in the perspective of possible exploitations of nanotechnology to improve the success and performance of
artificial fecundation techniques.
3 Safety and Utility of Nanomaterials on Reproduction and Development: An Update…