Jadi Salsabeel, Heynen Miriam, Luensmann Doerte, Jones Lyndon
Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Mol Vis. 2012;18:337-47. Epub 2012 Feb 4.
To determine the impact of incubation solution composition on protein deposition to silicone hydrogel (SH) contact lenses using a simplistic and a complex model of the tear film.
Three SH materials--senofilcon A (SA), lotrafilcon B (LB), and balafilcon A (BA)--were incubated in two different solutions; Solution A was a simplistic augmented buffered saline solution containing a single protein, whereas Solution B was a complex artificial tear solution (ATS), containing the augmented buffered saline solution in addition to proteins, lipids, and mucins (pH=7.4). The proteins of interest (lysozyme, lactoferrin, albumin) were radiolabeled with Iodine-125 (2% protein of interest) and the accumulation of the conjugated protein to the lens materials was determined after 1, 7, 14, and 28 days of incubation. Protein deposition was measured using a gamma counter and the raw data were translated into absolute amounts (µg/lens) via extrapolation from standards.
After 28 days, lysozyme uptake was significantly lower on BA lenses when incubated in Solution A (33.7 μg) compared to Solution B (56.2 μg), p<0.001. SA lenses deposited similar amounts of lysozyme when incubated in either Solution A (2.6 μg) or Solution B (4.1 μg), p>0.05. LB lenses also deposited similar amounts of lysozyme for both solutions (Solution A: 5.0 μg, Solution B: 4.7 μg, p>0.05). After 28 days, BA lenses accumulated approximately twice the amount of lactoferrin than the other lens materials, with 30.3 μg depositing when exposed to Solution A and 22.0 μg with Solution B. The difference between the two solutions was statistically significant (p<0.001). LB materials deposited significantly greater amounts of lactoferrin when incubated in Solution A (16.6 μg) compared to Solution B (10.3 μg), p<0.001. Similar amounts of lactoferrin were accumulated onto SA lenses regardless of incubation solution composition (Solution A: 8.2 μg, Solution B: 11.2 μg, p>0.05). After 28 days, albumin deposition onto BA lenses was significantly greater when lenses were incubated in Solution B (1.7 μg) compared to Solution A (0.9 μg), p<0.001. Similar amounts of albumin were deposited on SA lenses when incubated in either solution (0.6 μg versus 0.7 μg, p>0.05). LB lenses incubated in Solution A deposited more albumin compared to Solution B (0.9 μg versus 0.6 μg), p=0.003.
Protein deposition onto SH materials varied when contact lenses were incubated in either a complex ATS compared to a single protein solution. More lysozyme accumulated onto BA lenses incubated in a complex analog of the human tear film, whereas lactoferrin deposited onto SA lenses independent of incubation solution composition. To better mimic the ex vivo environment, future studies should use more appropriate analogs of the tear film.
使用泪膜的简单模型和复杂模型，确定孵育溶液成分对蛋白质在硅水凝胶（SH）隐形眼镜上沉积的影响。
三种SH材料——senofilcon A（SA）、lotrafilcon B（LB）和balafilcon A（BA）——在两种不同溶液中孵育；溶液A是一种简单的强化缓冲盐溶液，含有单一蛋白质，而溶液B是一种复杂的人工泪液溶液（ATS），除了蛋白质、脂质和粘蛋白外还含有强化缓冲盐溶液（pH = 7.4）。将感兴趣的蛋白质（溶菌酶、乳铁蛋白、白蛋白）用碘 - 125进行放射性标记（感兴趣蛋白质的2%），并在孵育1、7、14和28天后测定结合蛋白在镜片材料上的积累情况。使用γ计数器测量蛋白质沉积，并通过从标准品外推将原始数据转换为绝对量（μg/镜片）。
28天后，与溶液B（56.2μg）相比，在溶液A中孵育时，BA镜片上的溶菌酶摄取量显著降低（33.7μg），p < 0.001。SA镜片在溶液A（2.6μg）或溶液B（4.1μg）中孵育时沉积的溶菌酶量相似，p > 0.05。LB镜片在两种溶液中沉积的溶菌酶量也相似（溶液A：5.0μg，溶液B：4.7μg，p > 0.05）。28天后，BA镜片积累的乳铁蛋白量约为其他镜片材料的两倍，暴露于溶液A时沉积30.3μg，暴露于溶液B时沉积22.0μg。两种溶液之间的差异具有统计学意义（p < 0.001）。与溶液B（10.3μg）相比，LB材料在溶液A（16.6μg）中孵育时沉积的乳铁蛋白量显著更多，p < 0.001。无论孵育溶液成分如何，SA镜片上积累的乳铁蛋白量相似（溶液A：8.2μg，溶液B：11.2μg，p > 0.05）。28天后，与溶液A（0.9μg）相比，BA镜片在溶液B（1.7μg）中孵育时白蛋白沉积量显著更大，p < 0.001。SA镜片在两种溶液中孵育时沉积的白蛋白量相似（0.6μg对0.7μg，p > 0.05）。与溶液B（0.6μg）相比，LB镜片在溶液A中孵育时沉积的白蛋白更多（0.9μg），p = 0.003。
与单一蛋白质溶液相比，当隐形眼镜在复杂的ATS中孵育时，蛋白质在SH材料上的沉积有所不同。在模拟人泪膜的复杂溶液中孵育时，更多的溶菌酶积累在BA镜片上，而乳铁蛋白在SA镜片上的沉积与孵育溶液成分无关。为了更好地模拟体外环境，未来的研究应使用更合适的泪膜类似物。
