Effect of In-Ga-Al-P diode laser irradiation on angiogenesis in partial ruptures of Achilles tendon in rats.
OBJECTIVE
This study was conducted to analyze the effect of different irradiances of low-level laser therapy (LLLT) on angiogenesis after partial rupture of Achilles tendon of rats.


BACKGROUND



METHODS
Ninety-six animals were divided into three groups subject to treatment during 3, 5, and 7 days post-lesion. Thirty-two animals were used in each group. The groups were further divided into four subgroups with eight animals in each, receiving In-Ga-Al-P laser (660 nm) treatment at (1) mean output of 10 mW, (2) 40 mW during 10 sec, (3) a sham subgroup, and (4) a non-treatment subgroup. Each animal was subjected to a lesion of the Achilles tendon by dropping a 186-g weight from a 20-cm height over the tendon. Treatment was initiated 6 h post-injury for all the groups. Blood vessels were colored with India ink injection and were examined in a video microscope.


RESULTS
Laser exposure promoted an increase in blood vessel count when compared to controls. The 40-mW group showed early neovascularization, with the greatest number of microvessels after three laser applications. The 10-mW subgroup showed angiogenesis activity around the same time as the sham laser group did, but the net number of vessels was significantly higher in the former than in the controls. After seven irradiations, the subgroup receiving 40 mW experienced a drop in microvessel number, but it was still higher than in the control groups.


CONCLUSIONS
LLLT of different intensities seems to promote neovascularization in damaged Achilles tendons of rats after partial rupture compared to controls.
Salate
Ana C B
AC
Department of Physiotherapy, Federal University of São Carlos, São Paulo, Brazil.
Barbosa
Gisele
G
Gaspar
Patrícia
P
Koeke
Paulo U
PU
Parizotto
Nivaldo A
NA
Benze
Benedito G
BG
Foschiani
Daiane
D
D000125:Achilles Tendon / Q000293:injuries* / Q000473:pathology; D000818:Animals; D004195:Disease Models, Animal; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D018919:Neovascularization, Physiologic / Q000528:radiation effects*; D010784:Photomicrography; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D012039:Regional Blood Flow; D012421:Rupture / Q000532:radiotherapy; D012680:Sensitivity and Specificity; D013708:Tendon Injuries / Q000532:radiotherapy*