Muscular trauma treated with a Ga-Al-As diode laser: In vivo experimental study

The aim of the study was to verify in an experimental model the effects of laser therapy performed with Ga-bl-As diode lasers (780 nm, 2500 mW) on tra umatised muscles. Forty adult New Zealand male rabbits were divided into fo ur groups (A, B, C and D) of ten animals each. Each group of animals was fu rther divided into two subgroups of five animals each. The animals were sub mitted to muscular trauma for 7 min by clamping the posterior muscles of th e left thigh under general anaesthesia. Four days later, the rabbits in the B-1, B-2, C-1, C-2, D-1 and D-2 subgroups started daily laser therapy. The parameters utilised were: 150 J/cm(2) energy density, 3 W, 50 Hz in group B; 250 J/cm(2), 3 W, 100 Hz in group C; and 800 J/cm(2), 3 W, 0 Hz (continu ous output) in group D. The animals in subgroups A(1) and A(2) were used as untreated controls and allowed to heal spontaneously. In order to prepare samples for histological, histochemical and histomorphometrical studies, di ssection of the posterior muscle of the thigh was performed under general a naesthesia and before sacrifice, after five days of laser therapy in the su bgroups B-1, C-1 and D-1 and after ten days of laser therapy in subgroups B -2, C-2 and D-2. The samples of untreated subgroups A(1) and A(2) were subj ected to the same procedure and at the same times as the corresponding lase r-treated groups. The following parameters were analysed on muscular sample s: qualitative histological aspect (lactate dehydrogenase (LDH), cytochrome oxidase, acid phosphatase and alkaline phosphatase concentration with hist oenzymatic methods) and quantitative histomorphometric evaluation of muscul ar damage and tissue repair. Blood samples were drawn from each subgroup be fore the trauma and again before sacrifice to measure the creatine phosphok inase (CK) and LDH levels. The results obtained in the tables are shown. An alysis of the results showed a better qualitative and quantitative healing process in traumatised muscles treated with Ga-Al-As diode laser therapy th an in spontaneously healed ones. The results obtained with laser therapy we re confirmed as haematic, histoenzymatic and histomorphometric values. Acco rding to these results, there is a positive relationship between the biosti mulation properties of the laser and the healing of traumatised muscular ti ssue.