RESUMO
OBJECTIVE: Ouraim was to study influence of acute somatic pain on lysozyme activity of rats of different age: newborn, rats after eye opening, rats at the age of a month, adult and old rats. METHODS: Lysozyme activity was checked before pain irritation and 2, 30, 60, 120, 180min afterwards using Dorofeychuk's method in our modification. Pain effect was modeling by electrical stimulation. RESULTS: activity of lysozyme was 0. 434±0. 01 units in intact newborn rats, It was higher than in adult rats - 0.260 ±0.01 units (p <0.001) and it was unchanged during the experiment. We found low lysozyme activity in rats after eye opening - 0.015±0.003 units and it was stable during the experiment. Rats at the age ofa month had diphasic reaction: lysozyme activity was 0.191±0.01 units in intact rats, it increased up to 0.378±0.01 units (p <0.001) in 2 min after painful irritation and it decreased up to 0.113±0.02 units (p <0.001) in 30 min. Lysozyme activity was 0.260±0.01 units. Single-phase reaction was determined after acute painful irritation: increase of lysozyme activity after acute somatic pain up to 0,450±0,014 units (p <0.001). Lysozyme activity was 0.246±0.02 units in blood plasma of old rats. It decreased up to 0.1701±0.01 units (p <0.01) after painful irritation and it was 0.387±0.01 (p <0.001) in the end of the experiment. CONCLUSION: Response on pain irritation has differences in different groups. The common vector of pain response was the increase of lysozyme activity in rats at the age of a month, adult rats, rats after eye opening and old rats. Reaction of increasing lysozyme activity was strongly detected in adult rats. The results demonstrate preventive lasozyme resistance to potential tissue damage or contamination.