Resistance training and hormone replacement increase MMP-2 activity, quality and quantity of bone in ovariectomized rats

Abstract

-Aims:The aim of the present study was to investigate the influence of resistance training (RT) and hormone replacement (HR) on MMP-2 activity, biomechanical and physical properties bone of ovariectomized (OVX) rats. Methods: Sprague-Dawley female rats were grouped into six experimental groups (n = 11 per group): sham-operated sedentary (SHAM Sed), ovariectomized sedentary (OVX Sed), sham-operated resistance training (SHAM RT), ovariectomized resistance training (OVX RT), ovariectomized sedentary hormone replacement (OVX Sed-HR), and ovariectomized resistance training hormone replacement (OVX RT-HR). HR groups received implanted silastic capsules with a 5% solution of 17β-estradiol (50 mg 17β-estradiol/ml of sunflower oil). In a 12-week RT period (27 sessions; 4-9 climbs) the animals climbed a 1.1 m vertical ladder with weights attached to their tails. Biomechanical and physical bone analyses were performed using a universal testing machine, and MMP-2 activity analysis was done by zymography Results: Bone density and bone mineral content was higher in the RT and HR groups. The MMP-2 activity was higher in the RT and HR groups. The biomechanical analysis (stiffness, fracture load and maximum load) demonstrated better bone tissue quality in the RT associated with HR. Conclusion: The RT alone as well as when it is associated with HR was efficient in increasing MMP-2 activity, biomechanical and biophysical properties bone of ovariectomized rats.

Resistance Training Modulates the Matrix Metalloproteinase-2 Activity in Different Trabecular Bones in Aged Rats

“…This indicates that RT exerts important regulatory roles in bone ECM. Similarly, Souza et al 16 demonstrated that RT improved bone density, mineral content, and stiffness, besides upregulating MMP-2 activity of the tibia, in a similar hypoestrogenism model. These authors demonstrated that such effects are crucial for bone quality and bone health.…”

“…Our results concur with previous studies indicating that exercise programs exert important regulatory roles in bone ECM remodeling. Souza et al 16 and Shiguemoto et al 15 reported that RT (12 weeks, three times per week) contributed to an increase in MMP-2 activity in tibia of ovariectomized rats, which prevented the deleterious effects of menopause. Gelatinase activity in bone is important for aging, since it is associated with biological pathways related to bone protection and damage recovery, 18 besides playing a role in maintaining canalicular networks.…”

“…Clinical Interventions in Aging 2021: 16 accommodation, in which mechanosensitive cells adjust cytoskeletal stiffness in response to fluid flow and consequently bone mechanoadaptation processes, thereby inhibiting the release of important pro-osteoblastic signaling enzymes, such as MMP-2. It has been demonstrated that these adaptations may explain cellular saturation, in which bones become less mechanically sensitive with RT, and why a small number of loading cycles seems to have the same osteogenic potential as an exercise program.…”

Humanin, MOTS-c and physical exercise: A new perspective

“…Another RT effect known is to prevent and treat cases of osteoporosis and osteopenia [53][54][55] common in low levels of estrogen, both in the animal model of ovariectomy [56][57][58][59] as in studies with humans [54,60]. In this contexto, MOTS-c also mimicked the effects of physical exercise, being able to prevent significantly the loss of bone mass induce by ovariectomy analyzed by means of micro-CT [61].…”