Photo Induced NO-release In SNP And It’s Biological Applications Research

Nitric oxide (NO) is an important signal molecule and plays significant role in many physiological and biochemical processes, including the control of the blood pressure, the transmission of the nervous system, the immune response and cell apoptosis. With the development of bio-medicine and disease treatment, photodynamic therapy has become another new technical way comparing with traditional method like surgery, radiotherapy, chemotherapy. Meanwhile, the photoinduced NO-release is attached much attention. Developing a proper NO donor, to control the quantitative release of NO, and to take NO to a specific part become important issues to be solved. There are a variety of exogenous NO donors used clinically now. Sodium Nitroprusside (Na2 [Fe(CN)5NO]· 2H2O, SNP) has been widely applied clinically as vasodilator and as a drug to release NO, it has many important effects on the regulation of blood pressure.In this graduate thesis, we studied and analyzed the experimental kinetics of photoinduced NO-release in SNP solution, photoinduced production of NO free radical from SNP was proved with electron spin resonance spectroscopy(ESR), and the spin trapping shows a characteristic triplet signal of NO free radical. The quantity of NO-release from SNP solution upon photo irradiation at different number of wavelengths was detected using NO specific electrode, and the basic methods to control NO-release quantitatively were developed. The interactions between SNP and biological macromolecule DNA were studied under the light conditions, and the possible mechanism was analyzed. The effect of SNP on tumor cell growth were studied and compared with that upon photo irradiation, which providing a new basis for understanding the photo-induced biological effects and applications in clinical for SNP.There are mainly five parts in the following sections:Part 1, the recent progress on photodynamic therapy were summarized; the importance of SNP and the research related physical and chemical properties of NO and SNP were introduced.Part2, the spin trapping of released NO on SNP solution upon photoirradition were confirmed by the electron spin resonance (ESR); the amount of released NO from SNP was detected using NO specific electrode at different irradiation wavelengths, the basic way to regulate NO release in SNP solution using photo irradiation were developed.Part 3, the photo cleavage of pBR322DNA by SNP were studied used the agarose gel electrophoresis method and the mechanism was analyzed.Part 4, the CCK-8 method was used to study the inhibition of SNP on tumor cells growth (including:HeLa, HepG2 and MCF-7) with the light and without light conditions. It would provide new clue for the clinical treatment.Part 5, summary and outlook for the next work.