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Dietary alpha-ketoglutarate partially prevents age-related decline in locomotor activity and cold tolerance in Drosophila melanogaster

Bayliak, Maria M., Lylyk, Maria P., Sorochynska, Oksana M.
Biologia 2017 v.72 no.4 pp. 458-467
Drosophila melanogaster, adults, alpha-ketoglutaric acid, antioxidant activity, cold stress, cold tolerance, cold treatment, diet, females, free amino acids, glucose, locomotion, males, metabolism, proline, rearing, tricarboxylic acid cycle
Alpha-ketoglutarate (AKG), a key intermediate in the Krebs cycle and metabolism of amino acids, is one of dietary supplements studied actively during last decade. In this work, we examined the ability of dietary AKG to prevent age-related functional decline in D. melanogaster. For that, some metabolic processes and physiological functions, such as climbing activity and cold resistance, were studied in young (2 days post-eclosion) and middle-aged (24 days) D. melanogaster w¹¹¹⁸ adults maintained on AKG-supplemented diet. Both locomotor activity and cold resistance measured as chill coma recovery time (CCRT) impaired in middle-aged flies compared with young ones. Diet with 10 mM AKG improved climbing activity in middle-aged flies of both sexes. A positive impact of AKG on CCRT was found in young flies of both sexes and in middle-aged females. AKG-containing diet did not affect cold hardening in young flies, whereas middle-aged flies fed on AKG were more resistant to repeated cold treatments than control ones. Two-day old flies reared on AKG had higher free amino acid level, including that of proline. At 24-day age, AKG-fed females but not males had higher levels of free amino acids and glucose, and higher total antioxidant capacity than control ones. We conclude that both the enhancement of antioxidant capacity and synthesis of amino acids can contribute to AKG-promoted reduction in CCRT. However, since dietary AKG enhanced locomotor activity and resistance to repeated cold stresses in middle-aged both males and females, mechanisms of beneficial effects of AKG seem to be more complicated, that is discussed.