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Size-Dependent Cytotoxicity of Hydroxyapatite Crystals on Renal Epithelial Cells

Authors Sun XY, Chen JY, Rao CY, Ouyang JM

Received 30 September 2019

Accepted for publication 9 June 2020

Published 15 July 2020 Volume 2020:15 Pages 5043—5060


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Linlin Sun

Xin-Yuan Sun, Jia-Yun Chen, Chen-Ying Rao, Jian-Ming Ouyang

Department of Chemistry, Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632, People’s Republic of China

Correspondence: Jian-Ming Ouyang
Department of Chemistry Institute of Biomineralization and Lithiasis Research,Jinan University, Guangzhou 510632, People’s Republic of China
Tel +86 20-85223353

Background: Hydroxyapatite (HAP) is a common component of most idiopathic calcium oxalate (CaOx) stones and is often used as a nidus to induce the formation of CaOx kidney stones.
Methods: This work comparatively studies the cytotoxicity of four kinds of HAP crystals with different sizes (40 nm to 2 μm), namely, HAP-40 nm, HAP-70 nm, HAP-1 μm, and HAP-2 μm, on human renal proximal tubular epithelial cells (HK-2).
Results: HAP crystals reduce the viability and membrane integrity of HK-2 cells in a concentration-dependent manner and consequently cause cytoskeleton damage, cell swelling, increased intracellular reactive oxygen species level, decreased mitochondrial membrane potential, increased intracellular calcium concentration, blocked cell cycle and stagnation in G0/G1 phase, and increased cell necrosis rate. HAP toxicity to HK-2 cells increases with a decrease in crystal size.
Conclusion: Cell damage caused by HAP crystals increases the risk of kidney stone formation.

Keywords: cytotoxicity, nanocrystal, hydroxyapatite, crystal size, cell injury

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