The effects of low laser irradiation on angiogenesis in injured rat tibiae.
The influence of He-Ne laser radiation on the formation of new blood vessels in the bone marrow compartment of a regenerating area of the mid-cortical diaphysis of the tibiae of young adult rats was studied. A small hole was surgically made with a dentistry burr in the tibia and the injured area received a daily laser therapy over 7 or 14 days transcutaneously starting 24 h from surgery. Incident energy density dosages of 31.5 and 94.5 Jcm(-2) were applied during the period of the tibia wound healing investigated. Light microscopic examination of histological sections of the injured area and quantification of the newly-formed blood vessels were undertaken. Low-level energy treatment accelerated the deposition of bone matrix and histological characteristics compatible with an active recovery of the injured tissue. He-Ne laser therapy significantly increased the number of blood vessels after 7 days irradiation at an energy density of 94.5 Jcm(-2), but significantly decreased the number of vessels in the 14-day irradiated tibiae, independent of the dosage. These effects were attributed to laser treatment, since no significant increase in blood vessel number was detected between 8 and 15 non-irradiated control tibiae. Molecular mechanisms involved in low-level laser therapy of angiogenesis in post-traumatic bone regeneration needs further investigation.
Garavello
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Department of Semiconductors Instruments, Institute of Biology, State University of Campinas (UNICAMP), Campinas (SP), Brazil.
Baranauskas
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da Cruz-Höfling
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MA
D000818:Animals; D006371:Helium; D053685:Laser Therapy; D028022:Low-Level Light Therapy; D008297:Male; D009356:Neon; D018919:Neovascularization, Physiologic / Q000528:radiation effects*; D051381:Rats; D017208:Rats, Wistar; D013977:Tibia / Q000098:blood supply / Q000293:injuries*; D013997:Time Factors; D014945:Wound Healing / Q000528:radiation effects
D006371:Helium; D009356:Neon