Research On The Effect Of HAP Nanoparticles On The Proliferation Of K562 Cells

In recent years, nanoparticles have gained great attention from researchers due to their physical and characteristics as well as their potential application in medicine. Nanotechnology is a promising industry, and many researches have been conducted focused on the aspects of prevention and treatment of tumors. The effect of hydroxyapatite nanoparticles on cancer cells has aroused much interest.In this study, the sol of HAP nanoparticles was synthesized with the method of homogeneous precipitation, and its properties of size distribution, crystallization degree and morphology were characterized by laser granularity instrument, X-ray diffraction (XRD), and transmission electron microscope (TEM) respectively. The average particle size of the nanoparticles was 64nm. XRD patterns showed the characteristic absorbability peaks of HAP. TEM image revealed the nanoparticles were homogeneous, short rod-shaped.The prepared HAP nanoparticles were used for the treatment of human chronic myeloid leukemia K562 cells. The inhibition effect of the nanoparticles on the proliferation of K562 cells was measured by MTT assay.and growth curve test. The results suggested the nanoparticles of 0.56mmol/L had an inhibition rate of about 85.20%, while those of the other two groups with lower concentrations of were much lower.Further study on morphology observation, TEM, FCM, AgNORs staining and Feulgen staining showed that HAP nanoparticles of 0.56mmol/L affected K562 cells a lot. Morphology observation suggested that after treatment with HAP nanoparticles, the cell number decreased and the cell volumes reduced. TEM images indicated that a series of ultrastructural changes occurred after K562 cells treated with HAP nanoparticles of 0.56mmol/L, such as cytoplasmic dropsy and vacuolization, mitochondrial and endoplasmic reticulum(ER) swell, and gaps of nuclear pores increase. And even almost all the cytoplasm exfoliated, leaving a nearly naked nucleus. FCM results implied that cells were arrested in cell interphases (G2/M or G₁phase), and the percentage of apoptotic cells increased, thus inhibited cellproliferation and induced cell death. AgNORs staining revealed HAP nanoparticles of 0.56mmol/L induced the reduction of AgNORs content and nuclei diameter. Feulgen staining suggested HAP nanoparticles of 0.56mmol/L induced the decrease of DNA content.In short, HAP nanoparticles inhibited the proliferation of K562 cells dramatically in vitro. The ultrastucture changed a lot, the cells were arrested in cell interphases and the percentage of apoptotic cells increased;and AgNORs content and nuclei diameter as well as DNA content decreased. All these led to the inhibition of cell proliferation and thus induced cell death.