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 Bioenergy cropland expansion could be as bad for biodiversity as climate change
11.12.2018 | Senckenberg Forschungsinstitut und Naturmuseen

nachricht How glial cells develop in the brain from neural precursor cells
11.12.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor

11.12.2018 | Physics and Astronomy

Topological material switched off and on for the first time

11.12.2018 | Materials Sciences

NIST's antenna evaluation method could help boost 5G network capacity and cut costs

11.12.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>