Effects of physical training on metabolism of connective tissues in young mice

Abstract

The effects of physical training on the metabolism of collagen, calcium and glycosaminoglycans in various connective tissues were studied in male NMRI mice. The mice to be trained and their controls were about 3 weeks old (expt. I) and 8 weeks old (expt. II) at the commencement of training. The training was performed on a 5 degree inclined treadmill 5 days a week for 4 weeks in expt. I and for 3 weeks in expt. II. The daily exercise time was progressively increased from 20 min in the first week up to 80 min in the third week. The incorporation of 3H-proline to collagen hydroxyproline was increased by training in long bones, skeletal muscle and Achilles tendon, whereas the incorporation of 35S-sulphate into glycosaminoglycans of bones was lower for the trained compared to the control mice. The differences between the two groups in the incorporation of 45calcium were negligible. The results indicate that the metabolism of collagen is accelerated by physical training in several connective tissues in young rapidly growing mice, whereas the metabolism of glycosaminoglycans remains uneffected or is even retarded.

Moderate intensity physical training accelerates healing of full-thickness wounds in mice

“…The M/E lesion group presented a better rate of wound closure than the M/CG and M/E euthan groups on d 7 , sug-gesting that this result could express an effect of the animals' conditioning at a moderate-intensity physical training. No differences in wound closure were observed between the M/CG and M/E euthan groups on d 7 , confirming that the better wound closure of the M/E lesion group could be a chronic adaptation of moderate-intensity physical training ( Figure 1A). H/E lesion and H/E euthan presented delayed wound closure when compared to H/CG on d 7 ( Figure 1B).…”

“…The same occurred with the S/E lesion and S/E euthan groups, which showed delayed wound closure when compared to S/CG 7 days post-wounding ( Figure 1C). These findings suggest that physical training intensities of 80% VO 2max or higher were responsible for delayed wound contracture on d 7 . Physical training did not influence wound closure of the groups that trained at moderate, high and strenuous intensity on d 14 ( Figure 1A, B, and C).…”

“…Macroscopic changes induced by physical training included a better wound closure in moderate-intensity-conditioned animals, delayed wound contraction in the high and strenuous groups on d 7 , and an enhanced re-epithelialization in moderate and high-intensity-trained groups. Several microscopic findings confirm macroscopic data.…”

“…With strenuous-intensity physical training, the S/E euthan group presented an increased wound area when compared to S/CG and S/E lesion on d 4 . Both S/E lesion and S/E euthan groups showed delayed wound contracture when compared to S/CG animals on d 7 (C). The M/E euthan group showed the best re-epithelialization rate, followed by M/E lesion group.…”

“…These investigators showed that the effects of physical training are not restricted to the connective tissue of the locomotor system. Another study attempted to determine the effects of a few weeks of endurance-type training on the metabolism of collagen, calcium and glycosaminoglycans in bone, muscle, tendon, and skin of young mice, and showed that collagen metabolism was accelerated by physical training in the connective tissues studied, including the skin (7).…”