When alien organs or tissues are transplanted to a human organism (recipient), it usually rejects them as an immune response to transplantation - it is called rejection reaction. To prevent an organism from rejecting alien tissues, doctors prescribe patients large doses of chemical drugs. Are there any other ways to suppress the rejection?
 

Two recent decades brought scientists tons of data on how laser radiation reduces functional activity of an immune system under certain conditions and radiation doses. Such effects were first detected during treating head, eyes, skin and skin injuries, thyroid and adrenal glands. Besides that, people, who work with optical quantum generators for a long time, usually have weak immune system. And the last but not the least fact - scientists have tried to treat recipient's transplantation area during skin and bone transplantation with helium-neon laser radiation. They have detected that transplanted tissues were rejected slower than usual.
 

These data stimulated scientists from Severtsov Institute of Evolution and Ecology Problems (Russian Academy of Sciences) to analyze an effect of laser radiation on foreign skeletal muscles' transplantation results.
 

The experiments were performed on rats. Researchers have irradiated calf muscles of animal hind paws with helium-neon laser (with 632.8 nm wavelength). The rats had a series of 10 five-minute sessions for the period of two weeks. A group of control animals hasn't been exposed to laser radiation. After that, pairs of donor-recipient animal were selected among non-related rats. Donor calf muscles were transplanted to recipient's hind paw.
 

Scientists have performed four series of experiments. First one was for rats, which were not exposed to laser radiation (control animals); second one was for animals, exposed to laser radiation. In the third experiment scientists have treated with laser only donor rat. And in the fourth - only recipient animal was treated with laser. In two months the animals were killed, and changes in transplanted muscle tissue were examined.
 

About 50% of control rats still had fibers of donor muscle tissue, though obviously decaying. If a muscle has been treated before it was transplanted, its decay and replacement by connective tissue went faster than in the control group. The most distinct differences were detected when a treated muscle was transplanted to a rat, which hasn't been exposed to laser radiation.
 

Laser treatment of donor paws has hampered tissue rejection. In the case of transplanting of an untreated muscle to a treated recipient area scientists have detected that donor tissue remained unchanged for the longest period of time. Moreover, such muscles have had best response to nervous irritation, and even showed neuron process.
 

Scientists still have no explanation for how laser radiation changes skeletal muscles' properties. But they hope that the ability of low-intensity laser radiation to reduce immune response can be used in clinics during preparative courses for patients, waiting for foreign muscle transplantation. Pre-surgery radiation course may help to reduce doses of chemicals, which are usually prescribed to suppress the rejection of transplanted tissue.