Fotoprocesy indukowane promieniowaniem z zakresu bliskiej podczerwieni w erytrocytach i modelach błon biologicznych

• Autorzy: Komorowska M.

Warianty tytułu

EN

Photo-processes in erythrocytes and liposomes induced by near infrared radiation

• Języki publikacji: PL

Abstrakty

PL

Promieniowanie z zakresu bliskiej podczerwieni (NIR) jest składnikiem promieniowania słonecznego, o którym wiadomo, że głęboko penetruje tkanki. Może to świadczyć o fizjologicznym znaczeniu tego czynnika środowiskowego. Przedstawiono wyniki badań molekularnego mechanizmu działania promieniowania NIR na błony komórkowe lub modele błon. W ogólnym założeniu jest to próba wyjaśnienia na poziomie molekularnym mechanizmu regulacji dobowego zegara biologicznego oraz światłoterapii. Na podstawie porównania energii wiązań wodorowych oraz promieniowania NIR można sądzić, że wiązania wodorowe odgrywają rolę "anteny" w pierwotnym procesie absorpcji promieniowania. Do badań nad wpływem promieniowania NIR na liposomy, erytrocyty oraz micele zastosowano metody znaczników spinowych, obserwacje mikroskopowe, badanie wytrzymałości mechanicznej komórek erytrocytów i pomiar potencjału powierzchniowego oraz potencjału elektro-kinetycznego. Uzyskane wyniki badań umożliwiły sformułowanie następujących wniosków: Dehydratacja i połączona z tym procesem protonacja stanowią pierwotny proces na poziomie molekularnym oddziaływań promieniowania NIR z błonami biologicznymi. Proces ten przebiega tylko w roztworze o pH fizjologicznym. Rolę "anten" w pierwotnym procesie spełniają wiązania wodorowe o znacznej polaryzowalności protonowej. Skutki działania NIR obserwuje się nie tylko w błonach, lecz w całej objętości komórek.

EN

The daily luminary cycle is the most widely known and studied signal potentially initiating circadian rhythm synchronization. While eyes serve as photoreceptors for mammals, other vertebrates regulate this cycle by extraretinal light perception. The response of the human circadian clock to extraretinal light exposure was monitored by measuring body temperatures and melatonin concentrations corresponding to the cycle before and after the irradiation of the popliteal region. Light signals from this region of the human body can feasibly be transmitted by humoral phototransduction. Such a model postulates that hemoglobin and bilirubin act as photoreceptors due to their resemblance in chemical structure to light sensitive pigments in plants. It has not yet been determined which wavelengths of the sun spectrum are actually effective. This question is important for the medical treatment of SAD (Seasonal Affective Disorder), the winter type patients. SAD is a syndrome recurring annually, whose symptoms appear in autumn and winter, and withdraw in spring and summer. Late sunrise and short winter days at high latitudes are responsible for SAD symptoms, thus the circadian rhythm synchronized by light delays the normal human activity. Exposure to light is the most effectual medical treatment, and for this reason the effect of various wavelengths has been intensively studied. Meesters et al. has tested the effectiveness of red and near infrared radiation (NIR). Treatment was successful despite the low 18 lux radiation intensity applied, in contrast to commonly used 2500 lux of bright white light. Teicher et al observed a similar efficiency of red light. The arising dilemma therefore is whether near infrared radiation (NIR, effective in the treatment of SAD, acts on erythrocyte membranes. These cells are the principal constituents of blood, and their molecular mechanisms could be responsible for the mentioned radiation effects. The above question is justified by the fact that NIR is absorbed by several constituents of the red blood cell. Additionally, hemoglobin absorption bands of the NIR region are mainly electronic. The influence of NIR on various tissues has been reported in the last years. As a consequence of irradiation, change in cell membrane permeability, cloning efficiency alteration and UVA-like (long ultraviolet radiation stress were observed. The action of radiation depended on wavelength. Exposure to polarized radiation of (600-1600 nm and 130 mW/cm2, suppressed both the superoxide and hypochlorite anion production of human neutrophils, and serum opsonic activity. Laser radiation of low power stimulates the functions of the living organisms also. However, the molecular mechanisms of the interaction of radiation are not yet clear. In fact this radiation is absorbed mainly by overtones of stretching or combination vibrations -CH, -OH, -POH, -NH and SH groups; all of these molecules are involved in hydrogen bonds. Zundel et al. studied the easily polarizable hydrogen bonds between various proton donors and acceptors which are responsible for the presence of continua in IR spectra. Studies on these phenomena have demonstrated that many types of H-bonds, which form in proteins and H-bonded systems between side chains and phosphates, show large proton polarizability. When H bonds with large proton polarizability are present, what is common in biological systems like membrane surface, the proton within the system of H-bonds shifts and subsequently conformational changes are strongly interdependent. The proton transfer process can easily be controlled by local electric fields, caused by fixed charged groups, cations, polar molecules, even coupling proton motion with hydrogen bond stretching vibration. My suggestion corroborates fact that the energy of NIR 700-2000 nm 6-17 kJ per Avogadro's number of photons is comparable to the energy of hydrogen bonds 13-21 kJ/mol. The weakened bonds between membrane surface and bonding water enhance protonation such groups like phosphate, carboxylic, amine. Enhanced protonation induced by NIR leads to dehydration of the membrane surface. The aim of my work was: studies of the influence of this radiation in vitro on NIR irradiated bovine erythrocytes, multi-lamellar liposomes prepared from egg phosphatidylcholine (PC). Reversed TCAB (cetyltrimethylammonium bromide micelles and water solution of mixture aminoacids (glicyne, arginine, 1-glutamic and poly-(1-glutamic) acids and n-nitroaniline. As the light source the halogen lamp equipped with filters 700-2000 nm was used. Resolving the molecular mechanism of the near-infrared radiation influence on such structures. The properties measured of the materials under study and experimental methods: spin label technique, the membrane fluidity, phase transition and thermotropic properties, analysis of the spin label mobility (tumbling correlation time), processes on the membrane surface, the polarity of the membrane environment, the model proton transfer reaction induced by nir, the microscope observation, shape of cells, the agglomeration ability of liposomes, the mechanical properties of erythrocytes, the rate of hemolysis, the osmotic fragility, the electrostatic properties of membrane surface, the electrokinetic potential of erythrocyte membrane, the electrostatic surface potential - fluorescence measurements. Fluidity of erythrocyte membranes decreases or increases on dependence of the lipid region of the erythrocyte membrane, polarity decreases in the vicinity of polar heads, an oxidative factor outside the membranes is measured. Rates of hemolysis are dropped from the control value, the electrokinetic (zeta potential, measured electroforetically, was changes upon irradiation as well as the shape of cells. The isotropic tumbling correlation time calculated from EPR spectra increased for PC liposome membranes after irradiation. The temperature of the Arrhenius plots discontinuity for TEMPO-palmitate spin probe incorporated into PC bilayer is shifted toward higher values after irradiation. The ability of agglomeration of liposomes observed under optical microscope is considerably modified by irradiation The change of the electrostatic surface potential induced by Near-Infrared radiation is about - 36(+ -)15 mV. The analysis of the TEMPO-palmitate mobility clearly shows photodissociation of hydrogen bonded complexes, which forms this spin label on the surface of reversed micelles. NIR induces the reduction of TEMPO spin label when aminoacids are present in water solution. The phenomena observed are due to: o The hemoglobin excitation. The primary photochemical process is photodissociation of oxyhemoglobin to deoxyhemoglobin. The shape, ratio of hemolysis, structural changes and oxidative stress are consequences of the higher concentration of deoxyhemoglobin. o The protein, water and lipid overtones excitation. After NIR absorption the dehydration of the membrane surface occurs what leads to enhanced protonation and dissociation of hydrogen bonded complexes thus the electrokinetic potential is changed. The primary photo-effect of NIR radiation is dehydration of the erythrocyte cells and liposomes membranes.

Słowa kluczowe

PL

erytrocyty; błona biologiczna; promieniowanie; podczerwień

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Prace Naukowe Instytutu Fizyki Politechniki Wrocławskiej. Monografie
• Rocznik: 2001
• Tom: Vol. 35, nr 24
• Strony: 90--90
• Opis fizyczny: s., bibliogr. 232 poz.

Twórcy

autor

Komorowska M.

• Instytut Fizyki Politechniki Wrocławskiej, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław.