Dimitrova Daniela Z, Kubat Pavel, Dimitrov Stanislav, Belokonski Evgeni, Bogoeva Vanya
Department Excitable Structures, Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bldg. 21, 1113, Sofia, Bulgaria.
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Praha 8, Czech Republic.
Photodiagnosis Photodyn Ther. 2014 Sep;11(3):391-9. doi: 10.1016/j.pdpdt.2014.06.002. Epub 2014 Jun 10.
Considering the important roles of porphyrins in biological systems and their promising use in photodynamic therapy (PDT), the present work investigated the photophysical properties of palladium(II) 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin (PdTSPP) and the effects of non-activated by light form of this porphyrin on contractile behaviour of isolated healthy endothelium-denuded human mesenteric arteries.
The photophysical characterisation of PdTSPP: the formation of the triplet states and the singlet oxygen were studied using laser flash photolysis. The effect of PdTSPP on the isometric contraction of artery segments from human mesentery was assessed utilising the precise method of artery isometric tension recording using Mulvany-Halpern wire myograph.
We found that PdTSPP had a high lifetime of the triplet states τT=270μs. The calculated Stern Volmer rate constant kq=1.7×10(9)M(-1)s(-1) showed an efficient quenching by oxygen that indicated formation of singlet oxygen, O2((1)Δg). The photophysical parameters of PdTSPP, in particular its ability to generate O2((1)Δg) has defined it as an exceptionally interesting molecule for PDT. The results of the contraction study showed that PdTSPP applied in increasing concentrations (1-100μM) had no effect on the basal tone of human mesenteric artery under isometric condition. Furthermore, PdTSPP failed to potentiate or to attenuate the isometric contraction of the artery preparations precontracted with high extracellular potassium (42mM KCl) or with 1nM endothelin-1.
The excellent photophysical properties of PdTSPP as well as the lack of an effect on the contractility of human vasculature in vitro characterise PdTSPP as a suitable compound for potential medical applications.
鉴于卟啉在生物系统中的重要作用及其在光动力疗法（PDT）中的潜在应用前景，本研究调查了5,10,15,20-四（4-磺基苯基）卟啉钯（II）（PdTSPP）的光物理性质以及该卟啉的非光活化形式对分离的健康去内皮人肠系膜动脉收缩行为的影响。
PdTSPP的光物理表征：使用激光闪光光解研究三重态的形成和单线态氧。利用Mulvany-Halpern线肌动描记器精确记录动脉等长张力的方法，评估PdTSPP对人肠系膜动脉段等长收缩的影响。
我们发现PdTSPP的三重态寿命τT = 270μs。计算得到的斯特恩-沃尔默速率常数kq = 1.7×10⁹M⁻¹s⁻¹表明其能被氧有效猝灭，这表明形成了单线态氧O₂(¹Δg)。PdTSPP的光物理参数，特别是其产生O₂(¹Δg)的能力，使其成为光动力疗法中一个极具吸引力的分子。收缩研究结果表明，在等长条件下，以递增浓度（1 - 100μM）应用PdTSPP对人肠系膜动脉的基础张力没有影响。此外，PdTSPP未能增强或减弱用高细胞外钾（42mM KCl）或1nM内皮素-1预收缩的动脉制剂的等长收缩。
PdTSPP优异的光物理性质以及在体外对人体血管收缩性无影响的特点，使其成为潜在医学应用的合适化合物。
