title: In vivo comparison of simple and double-fractionated low-level laser irradiation schemes on the healing of rat skin lesions.
abstract: OBJECTIVE
  To compare the efficacy of a simple irradiation scheme with that of a double-fractionated irradiation scheme on the healing of rat skin lesions using in vivo monitoring of tissue diffuse reflectance.
  
  
  BACKGROUND
  Low-level laser therapy (LLLT) is used in medicine for treating a wide range of pathological conditions. The practical benefits of laser treatment of acute and chronic conditions were obtained, using a single session of irradiation per day.
  
  
  METHODS
  Thirty Wistar rats were divided into three experimental groups (controls, simple laser irradiation scheme, and double-fractionated laser irradiation scheme). A skin lesion was created on the calf of the right hind leg of all rats. The laser irradiation parameters were lambda = 635 nm and power = 15 mW. The exposure time was 600 s for the simple laser irradiation scheme and 300 s x 2 for the double-fractionated laser irradiation scheme on 3 consecutive days. The optical properties of tissue were studied by processing and analyzing the diffuse reflectance spectra of injured skin, acquired before and after each laser irradiation.
  
  
  RESULTS
  The results demonstrate that, using a simple laser irradiation scheme (single daily irradiation session: t exp 1 =600 s, power = 15 mW, lambda = 635 nm), healing of the skin lesion began after 3 consecutive treatment days. The application of the double-fractionated laser irradiation scheme (2 daily irradiation sessions: t exp 2 = t exp 1/2 = 300 s, power = 15 mW and lambda = 635 nm) led to a reduction in treatment time to 2 days.
  
  
  CONCLUSIONS
  In conclusion, a double-fractionated irradiation scheme is more efficient than simple irradiation scheme for LLLT in rat skin lesions.
authors.affiliation: National Institute of Research and Development for Optoelectronics, Magurele, Romania. micalin@inoe.inoe.ro
authors.forename: Mihaela Antonina
authors.initials: MA
authors.lastname: Calin
authors.forename: Simona
authors.initials: S
authors.lastname: Botea
mesh_terms: D000818:Animals; D028022:Low-Level Light Therapy / Q000379:methods*; D011879:Radiotherapy Dosage; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000293:injuries* / Q000528:radiation effects*; D013997:Time Factors; D014945:Wound Healing / Q000528:radiation effects*