RESUMEN
BACKGROUND & AIMS: Creatine is a dietary supplement with potential capacity to stimulate the phosphocreatine pathway and protein synthesis, through the stimulation of the PI3-K/AKT and mTOR cascade, its use in populations with reduced muscle preservation capacity (such as the older adults) can be an interesting and low-cost alternative. The aim of the present study was to evaluate the morphological, stereological and morphometric effects of the use of creatine monohydrate for 8 weeks on the renal, hepatic and muscular tissues of 26-month-old Wistar rats. METHODS: Twelve Wistar rats were divided into two groups of six animals each. Group 1 was not supplemented with creatine and received a standard diet consisting of water and chow. Group 2 received the same diet, but was supplemented with creatine monohydrate at a dose of 0.3 mg/kg of body weight diluted in 200 ml of drinking water for 8 weeks. RESULTS: Supplementation reduced muscle mass loss as indicated by the perimeter of the perimysium (group 1: 114.6 µm; group 2: 65.2 µm) and endomysium (group 1: 41,239.3 µm; group 2: 12,437.6 µm) compared to the non-supplemented group. In addition, a larger cross-sectional area was observed in group 2. No significant kidney or liver damage was observed in the supplemented group. CONCLUSIONS: The use of creatine is considered safe in the animal model used, as this amine does not cause glomerular reductions or hepatic degeneration.