Effects of CO2 laser amputation on Hydra regeneration

In order to investigate laser effects on biological specimens, Hydra, a coelenterate with high regeneration rate, was observed for ten days during regeneration after CO2 laser cutting. Control animals were cut with a razor blade immediately below the tentacle whorl under a dissecting microscope while they were in small glass petri dishes. They regenerated tentacles completely 8 to 10 days from the cutting. Hydra were cut in the same position with CO2 laser. As a first step, we studied the effect of the laser beam on the normal behaviour of hydra. For the cutting, we used four different power intensities: 0.5, 1.0, 1.5 and 2.0 W. At different power intensities the animals regenerated the tentacles. However in about 20% of the animals the amputation performed with 1 and 1.5 W originated a quicker regeneration of tentacles. No effect was observed on asexual reproduction of the polyps and therefore also no change of the bud index.