Tortoise blood fights radiation sickness

By MARINA KOZLOVA, UPI Science News   |   May 6, 2002 at 4:21 PM
share with facebook
share with twitter

A unique chemical extracted from the blood of Central Asian tortoises can be used to treat radiation sickness, Uzbek scientists told United Press International.

The preparation called TT2 is made up of a string of amino acids, the basic building blocks of proteins. In animal tests the preparation seems to increase the number of the body's immune cells, which helps it fight off the damage done by radiation.

TT2 relieved irradiated test animals of the effects of radiation sickness, Vitali Alexandrov, senior scientist at the radiation biochemistry and cytology laboratory of the Uzbek Institute of Biochemistry, told UPI.

Their survival rate increased as the dosage of TT2 was increased, Alexandrov said.

The tortoise, Testudo horsfieldi, enjoys a unique radiation resistance in the animal world. The lethal dose required to kill up to 50 percent of a population of the species is 40,000 Roentgens, compared to only 800 Roentgens needed to kill 50 percent of a human population. The tortoise can survive doses of tens of thousands of Roentgens.

Scientists explained that Testudo horsfieldi sleeps up to ten months a year. In April, the creature wakes up and begins to make up for its slumber by eating voraciously, copulating and laying eggs. During this period, the tortoise's body produces a special growth substance that affects the amino acids in its blood. This substance forms the basis for TT2.

Scientists had developed earlier substances from Testudo horsfieldi to treat radiation sickness. Called Tortesin and TAU-Tortesin, the substances were extracted from the livers and spleens of tortoises but necessitated killing the animals.

TT2 is extracted from the blood and therefore does not require the tortoise to be killed. Instead, scientists draw tortoise blood from the legs with a syringe.

TT2 also is more effective than the previous substances, the scientists said.

"According to the survivability ... test, TT2 is the best among all known specific preparations," Alexandrov said.

TT2's efficacy has been demonstrated in experiments on mice, rats and rabbits. Mice subjected to up to 750 Roentgens were given TT2 by injection two hours later. More than 70 percent of the mice survived.

Alexandrov said he has taken TT2 himself.

"Stimulation of (the blood's production) of so-called stem cells is the novelty," Prof. Fuat Memetov from the Oncology and Radiology Institute of the Uzbek Ministry of Public Health told UPI.

"The preparation has no analogues," Memetov said, referring to the fact that there are no medications similar to TT2.

Alexandrov told UPI the next step is to carry out preclinical and clinical trials and prepare documentation. Because this will cost tens of thousands of dollars, which is not available in Uzbekistan, Alexandrov and his colleagues will seek a foreign investor or a large pharmaceutical company.

He said TT2 may also find uses in treatments for blood disorders and cancer as well as for victims of radiation accidents or terrorist acts. Present radiation sickness treatment involves bone marrow transplants plus antibiotics and blood transfusions.

In addition to Alexandrov, TT2 was invented by Azim Turdyev, former head of the radiation biochemistry and cytology laboratory and currently a professor at Bar-Ilan University in Israel, and Rustam Usmanov, present head of the laboratory.

Related UPI Stories
Trending Stories