Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nitrites Help To Struggle Against Ischemia Retinae

27.03.2008
Nitrites dilate vessels in case of hypoxia and protect retina from ischemia.

The conclusion has been made by specialists of the Moscow Research Institute for Eye Diseases named after Gelmholtz and the N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences. Their discovery is the outcome of a series of experiments on rabbits. It is premature to talk about its clinical use.

Ischemia is a rather widespread pathology of retina and optic nerve. It is provoked by different reasons, including primary hypertension and insular diabetes. An important role in retina pathology development is played by shortage of nitric oxide, which is synthesized in the organism from arginine. Theoretically speaking, nitrites can turn into nitric oxide under the influence of some enzymes. However, till recently, nobody could prove that such reaction does take place in a living organism. The Moscow researchers succeeded to do that based on the acute ischemia retinae model developed by them.

The rabbit is a favorite object for ophthalmologists’ investigations. The animals underwent laser coagulation of eye-ground vessels. The experimentalists have chosen such a place for exposure so that several impulses could capture the maximum number of vessels and if possible not to traumatize surrounding tissues. The laser provokes stable vasospasm and, consequently, ischemia. The outcomes of researchers’ action were estimated by the rabbits’ eye-ground photographs.

After coagulation, the rabbits’ eye vessels become desolate and abruptly reduced in diameter. Right after laser exposure, sodium nitrite in physiological solution was intraperitoneally introduced to the rabbits on the basis of 20 mg per 1 kilogram of live weight. As soon as a quarter of an hour after the injection, the retina vessels directly behind the laser impact zone began to fill with blood and the blood circulation restored in them. At that, the nitrite injection to an animal with normal vessels almost did not provoke their dilation. The researchers assume that nitrite in the organism is able to quickly reduce to nitric oxide, which sharply relaxes vessels, but only in case of oxygen shortage.

In the course of a next series of experiments the researchers clarified if preliminary nitrite injection prevented vessel constriction. For this end, a rabbit was initially injected sodium nitrite, and 15 minutes later the researchers cauterized vessels by laser and observed changes in them. In this case, laser impact provoked only a short-term vasospasm of the vessel, which quickly filled with blood and restored the “flow capacity”.

The same results were obtained by the researchers via an independent method when observing changes in photoelectric activity of a rabbit’s retina. The electroretinogram analysis has shown that laser coagulation of vessels impairs functional state of retina, which restores within 7 days without outside interference. The sodium nitrite injection right after laser coagulation accelerates the rehabilitation process significantly, and the preparation injection prior to laser exposure virtually fully protects retina from injury. At that, even strong laser impact can not provoke abrupt constriction and desolation of animals’ vessels.

Thus, the outcomes obtained by two independent methods prove that nitrites presence in vessels protects the retina from acute ischemia. Mechanism of such action, apparently, consists in the fact that under oxygen shortage in the organism, sodium nitrite can reduce to nitric oxide at concentrations that are sufficient for full vessel relaxation.

Olga Myznikova | alfa
Further information:
http://www.informnauka.ru

Further reports about: Injection Laser Oxide Protect Retina coagulation ischemia nitric nitrite outcome sodium vessel

More articles from Life Sciences:

nachricht Molecular microscopy illuminates molecular motor motion
26.07.2017 | Penn State

nachricht New virus discovered in migratory bird in Rio Grande do Sul, Brazil
26.07.2017 | Fundação de Amparo à Pesquisa do Estado de São Paulo

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>