Excess of eccentric exercise, mechanical load on the knee joint and osteoarthritis in C57BL/6 mice

Author(s)

Gustavo Paroschi Morais

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP)
• Defense date: 2019-10-24

Examining board members

Adelino Sanchez Ramos da Silva; Walter Herzog; Renato de Moraes; Donato Americo Rivas

• Advisor: Adelino Sanchez Ramos da Silva

Abstract

Osteoarthritis (OA) is a chronic degenerative disease that induces cartilage degradation and is very common in the knee joint. OA progression occurs due to excess load in the joint as well as systemic or local inflammation. Physical exercise is a commonly used therapy to prevent and treat this illness, attenuating the symptoms. However, studies that exhibit controversial results still exist, which could be explained by the volume, intensity, and type of exercise used. Scientific investigations demonstrate that excessive exercise may cause an onset of osteoarthritis, which can be explained through joint overload, and/or increasing enzymes related to cartilage degradation. Furthermore, our study group has verified that mice submitted to excessive downhill training presented low-grade systemic inflammation, evidenced by an increase in pro-inflammatory cytokines. The mechanical, histological and biochemical changes in the skeletal muscle, such as the increase in the number of sarcomeres in series, can explain the highest level of inflammation in this type of exercise. Therefore, the aim of the present study was to verify the differences in osteoarthritis progression, muscular inflammation, and shift in sarcomere structure among C57BL/6 mice moderately trained in downhill and uphill, and excessively trained in downhill and uphill. The mice were divided into 5 groups: sedentary (S; sedentary mice); trained downhill (TRD; mice submitted to downhill training protocol); trained uphill (TRU; mice submitted to uphill training protocol); excessive downhill training (ETD; mice submitted to downhill overtraining protocol); excessive uphill training (ETU; mice submitted to uphill overtraining protocol). The methods, results, and discussion regarding these findings are presented in the format of two manuscripts. The level of significance adopted was p<=0.05 (AU)

• FAPESP's process: 16/25766-4 - Excess of eccentric exercise, mechanical load on the knee joint and osteoarthritis in C57BL/6 mice
• Grantee: Gustavo Paroschi Morais
• Support Opportunities: Scholarships in Brazil - Master