Effects of Whitlockite Nanoparticles on Germ Cell Development and Spermatogenesis in Japanese Medaka

Abstract

Whitlockite, the second most abundant bone mineral, was found promising in regenerative engineering of damaged bone tissue because of its high bone remodelling potential. However, no studies have investigated its effects on other organ systems and the environment. It is essential to study this aspect as whitlockite is known to dissolute at non-acidic pH. Hence, the effects of whitlockite nanoparticles on embryonic development, germ cell differentiation, and gametogenesis were explored here in an aquatic species, the Japanese medaka. Exposure to nano-whitlockite of 59.67±10.21 nm size showed no impact on medaka embryo development, survivability, and hatchability. However, it caused an increase in germ cell count in a significant number of XY males exposed to 0.1 microg/L nano-whitlockite compared to untreated controls and larvae exposed to 0.01, 1 and 10 microg/L. Interestingly, exposed XX females showed no such effect. Furthermore, exposure to nano-whitlockite at stages after attaining sexual maturity did not affect the reproductive systems of medaka males and females. Importantly, this study revealed that germ cell development during the embryonic period was sensitive to nano-whitlockite exposure, warranting detailed analyses and more studies in this regard using these particles.