The dose-dependent impact of γ-radiation reinforced with backscatter from titanium on primary human osteoblasts

Figures & data

Figure 1. Macro photos, scanning electron microscopy images and 3D surface topography of the three different test surfaces. Surface roughness (S_a) of the test surfaces was calculated from the obtained profilometry data, Ti: 0.25 ± 0.01 µm; TiF: 1.94 ± 0.16 µm; TCP: 9.34 ± 0.21 nm (n = 3).

Figure 2. The number of irradiated human osteoblasts (hOBs) cultured in growth medium (GM) or differentiation medium (DM) on minimally rough machined titanium (Ti) and moderately rough fluoride-modified titanium (TiF), and the relative confluence of hOBs on tissue culture polystyrene (TCP), 21 days post-irradiation. Data represent mean values ± standard error of the mean (SEM) from three different experiments (n = 9) and are presented as % of unirradiated controls (red line) on the same surfaces (Ti, TiF or TCP) and in the same type of culture medium (GM or DM). The significance level is set to p values ≤0.05 toward control (red line) (a), toward 2 Gy (b) and toward 6 Gy (c).

Figure 3. Confocal images from one of the experiments. Morphology of cell nuclei, collagen and actin production of hOBs cultured for 21 days in growth medium (GM) (n = 3) or differentiation medium (DM) (n = 3) on minimally rough machined titanium (Ti) and moderately rough fluoride-modified titanium (TiF), after no irradiation and after 10 Gy (A). Quantification of collagen (B) and actin (C) production of hOBs cultured for 21 days in GM (n = 3) or DM (n = 3), on Ti and TiF, after single doses of 2, 6 and 10 Gy. The data represent mean values ± standard error of the mean (SEM) from three different experiments and are presented as % of unirradiated controls (red line) on the same surfaces (Ti or TiF) and in the same type of culture medium (GM or DM). The significance level is set to p values ≤ 0.05 toward control (a), and toward 6 Gy (c).

Figure 4. Alkaline phosphatase (ALP) activity measured in growth medium (GM) (n = 9) and differentiation medium (DM) (n = 9) of human osteoblasts (hOBs) on days 1 and 21 post-irradiation (A), and the effects of radiation on the mineral deposition of hOBs after 21 days of culture (B) on minimally rough machined titanium (Ti) (n = 6), moderately rough fluoride-modified titanium (TiF) (n = 6), and tissue culture polystyrene (TCP) (n = 9), after single doses of 2, 6 and 10 Gy. The data represent mean values ± standard error of the mean (SEM) from three different experiments and are presented as % of unirradiated controls (red line) on the same surface (Ti, TiF or TCP) and timepoint. The significance level is set to p values ≤ 0.05 toward control (a), toward 2 Gy (b) and toward 6 Gy (c).

Figure 5. Secretion of osteogenic biomarkers; dickkopf-related protein (DKK-1) (A), interleukin-6 (IL-6) (B), osteopontin (OPN) (C) and osteoprotegerin (OPG) (D) to the cell culture medium (GM and DM) measured on days 1 and 21 post-irradiation, from human osteoblasts (hOBs) cultured on minimally rough machined titanium (Ti) (n = 9), moderately rough fluoride-modified titanium (TiF) (n = 9) and tissue culture polystyrene (TCP) (n = 9) after single doses of 2, 6 or 10 Gy. The data are presented as % of unirradiated controls (red line) on the same surfaces (Ti, TiF or TCP) and timepoints. Data were adjusted to the relative cell number on day 21 and represent mean values ± standard error of the mean (SEM) from three different experiments. The significance level is set to p values ≤ 0.05 toward control (a), toward 2 Gy (b), toward 6 Gy (c) and toward 10 Gy (d).

Data availability statement

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.