title: Excessive eccentric exercise-induced overtraining model leads to endoplasmic reticulum stress in mice skeletal muscles.
abstract: OBJECTIVE
  The present study verified the responses of selected endoplasmic reticulum (ER) stress proteins (i.e., BiP, ATF-6, pIRE1, pPERK, and peIF2alpha) in mice skeletal muscles after three different running overtraining (OT) protocols with same external load (i.e., intensity vs. volume), but performed in downhill, uphill and without inclination.
  
  
  METHODS
  The rodents were randomly divided into control (CT; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up) and overtrained by running without inclination (OTR) groups. The incremental load test and exhaustive test were used as performance parameters. Forty hours after the exhaustive test performed at the end of the OT protocols (i.e., at the end of week 8) and after a 2-week total recovery period (i.e., at the end of week 10), the extensor digitorum longus (EDL) and soleus muscles were removed and used for immunoblotting.
  
  
  RESULTS
  For both skeletal muscle types, the OTR/down protocol increased the pIRE-1, pPERK and peIF2alpha, which were not normalized after the total recovery period. At the end of week 8, the other two OT protocols up-regulated the BiP, pPERK and peIF2alpha levels only for the soleus muscle. These ER stress proteins were not normalized after the total recovery period for the OTR/up group.
  
  
  CONCLUSIONS
  The above findings suggest that the OTR/down protocol-induced skeletal muscle ER stress may be linked to a pathological condition in EDL and soleus muscles.
authors.affiliation: Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, USP, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Bruno C
authors.initials: BC
authors.lastname: Pereira
authors.affiliation: Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, USP, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Alisson L
authors.initials: AL
authors.lastname: da Rocha
authors.affiliation: Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, USP, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Pinto
authors.affiliation: Sport Sciences Course, Faculty of Applied Sciences, State University of Campinas (UNICAMP), Limeira, São Paulo, Brazil.
authors.forename: José R
authors.initials: JR
authors.lastname: Pauli
authors.affiliation: Exercise Biochemistry and Physiology Laboratory Postgraduate Program in Health Sciences, Health Sciences Unit, University of Far Southern Santa Catarina, Criciúma, Santa Catarina, Brazil.
authors.forename: Claudio T
authors.initials: CT
authors.lastname: de Souza
authors.affiliation: Sport Sciences Course, Faculty of Applied Sciences, State University of Campinas (UNICAMP), Limeira, São Paulo, Brazil.
authors.forename: Dennys E
authors.initials: DE
authors.lastname: Cintra
authors.affiliation: Sport Sciences Course, Faculty of Applied Sciences, State University of Campinas (UNICAMP), Limeira, São Paulo, Brazil.
authors.forename: Eduardo R
authors.initials: ER
authors.lastname: Ropelle
authors.affiliation: School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.
authors.forename: Ellen C
authors.initials: EC
authors.lastname: de Freitas
authors.affiliation: Laboratory of Physiology and Sport Performance (LAFIDE), Faculty of Sciences, Univ Estadual Paulista - UNESP, Bauru, São Paulo, Brazil.
authors.forename: Alessandro M
authors.initials: AM
authors.lastname: Zagatto
authors.affiliation: Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, USP, Ribeirão Preto, São Paulo, Brazil; School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil. Electronic address: adelinosanchez@usp.br.
authors.forename: Adelino S R
authors.initials: AS
authors.lastname: da Silva
mesh_terms: D000818:Animals; D001835:Body Weight; D004435:Eating; D059865:Endoplasmic Reticulum Stress; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000009:adverse effects*; D012420:Running
keywords: ER stress; Mice; Overtraining protocols; Skeletal muscles