SiO₂ Nanoparticles Alter Basal Intracellular Calcium Concentration by Reducing TRPC1 Channel Expression in Human Retinal Pigment Epithelium Cell Line

Objective: Nowadays, the use of SiO2-based nanoparticles in the treatment of ocular diseases has significantly increased. Nanoparticles (NPs) can easily penetrate biological membranes and interact with membrane components such as ion channels. SiO2 nanoparticles (SiO2 NPs) are one of the most common used NPs in health field. There are limited studies determining the effects of SiO2 NPs on the retinal cells. In this study, it was aimed to investigate the effect of SiO2 NPs on transient receptor potential canonical 1 (TRPC1) expression and intracellular basal calcium concentration in retinal pigment epithelial (RPE) cells. Methods: Cultured hARPE 19 cells were divided into four groups as control, 50 mu g/mL SiO2, 100 mu g/mL SiO2, and 150 mu g/mL SiO2. All groups except control were incubated for 24 h with SiO2 NPs. Subsequently, the expression level of TRPC1 was assessed utilizing the real-time polymerase chain reaction (PCR) method. Basal intracellular calcium concentration [Ca2+](i) was measured using confocal microscopy. Results and Discussion: Relative TRPC1 gene expression levels and basal [Ca2+](i) decreased significantly in the SiO2 dose groups compared to control group. There was a significant correlation of relative channel expression level and basal [Ca2+](i). Conclusions: Our results show that SiO2 NPs reduce the expression of TRPC1 channels, leading to a decrease in basal [Ca2+](i). The decrease in [Ca2+](i) is likely to affect calcium-related physiological processes in RPE cells. However, more investigations are required regarding this subject.