Nanobiotechnology for health-care

Gold and silver nanoparticles affect pituitary component of reproductive system in male rats
V.Ye. Kalynovskyi1, O.O. Kalmukova1, A.S. Pustovalov1, G.Ya. Grodzyuk2, N.S. Andryushina2, M.E. Dzerzhynsky1
1 Cytology, Histology and Reproductive Medicine Department, Educational and  Scientific Center «Institute of Biology and Medicine», Taras Shevchenko National University of Kyiv. Ave. Glushkov 2, 03022 Kyiv, Ukraine.
E-mail: squilchuw@gmail.com
2 Nanomedtech-LLC, 68 Antonovycha Str., 03680 Kyiv, Ukraine.

The reproductive toxicity of metallic nanoparticles is now widely accepted yet not fully understood. Numerous in vitro investigations proved cytotoxic and genotoxic effects possessed by spherical gold and silver nanoparticles. However, in vivo experiments result in different observations, which greatly depend on the composition of a particular nanometal solutions; size and shape of particles; dose and route of administration; age and general physiological state of experimental animals. Our study was aimed to evaluate potential effects of spherical gold and silver nanoparticles on the intermediate component of hypothalamic-pituitary-gonadal axis.
The experiment was carried out on the albino laboratory rats aged 1 and 6 month (n=24 each). Nanoparticle (average diameter 8-12 nm) solutions were prepared through the reduction of silver nitrate (for nanosilver) or sodium tetrachloroaurate (III) in the presence of sodium polyphosphate. Animals of experimental group were intraperitoneally injected with nanometals (1 mg/kg bw) for 10 days. We also had two control groups (saline and sodium polyphosphate). Next, animals were sacrificed, their pituitaries fixed in Bouin’s fluid and routinely processed. Histological samples were stained with Herlant’s trichrome stain to reveal gonadotrophs. In these cells were measured cross-sectional area of cells and their nuclei, as well as nuclear-to-cytoplasmic (N:C) ratio.
We found that both types of nanoparticles caused significant reduction of cytoplasm in 1-month-old animals with no effect on nuclear cross-section. The N:C ratio was elevated in the nanogold group only. The morphological changes in gonadotrophs indicated inhibition of secretory processes. Findings in older age group were comparable to the younger one, although nanosilver showed less adverse effects. To sum up, we found that gold and silver nanoparticles cause age-independent inhibition of reproductive system at the pituitary level.