OBJECTIVE: To analyze the activity and electrophoretic pattern of the enzyme LDH in response to treadmill training, in rats undergoing photostimulation using low-level laser therapy (LLLT) (780 etam). METHOD: Fifty-four 30-day-old male Winstar rats initially weighing 112 ± 4.7g were divided into four groups. Two groups remained at rest: resting control group (RCG, n= 9) and resting LLLT group (RLG, n= 10). The other two groups underwent a five-week treadmill program of aerobic training and non-continuous incremental effort tests, with the aim of determining the anaerobic limit. One of the latter was an exercise control group (ECG, n= 16) and the other was an exercise LLLT group (ELG, n= 19). LLLT was applied to the quadriceps, gluteus maximus, soleus and tibialis anterior, bilaterally, immediately after each training session, using the following: 3.8 J/cm²; 15 mW; time 10 s; continuous mode. Samples of the soleus, tibialis anterior and heart were removed 48 hours after the last exercise session for electrophoretic and spectrophotometric analysis. The statistical analyses used were the ANOVA and post-hoc Tukey tests. The level of statistical significance was set at p< 0.05. RESULTS: Reductions in LDH activity caused by laser (from 19% to 30%), exercise (from 41% to 66%) and combined action (from 47% to 66%) were observed (p< 0.01). Electrophoresis showed predominance of subunit B in the soleus and heart, and predominance of subunit A in the tibialis anterior. CONCLUSION: The data suggest that the animals have an adaptive response to aerobic training with LLLT, towards optimizing the oxidative pathway.
LDH; Electrophoresis; endurance training; rat; LLLT
