Effects of dietary α‐ketoglutarate supplementation on the antioxidant defense system and HSP 70 and HSP 90 gene expression of hybrid sturgeon A cipenser schrenckii ♀ ×  A . baerii ♂ exposed to ammonia‐N stress

Abstract

This study was conducted to determine the effects of dietary a-ketoglutarate (AKG) supplementation on the antioxidant defense system and gene expression of heat shock protein (HSP) 70 and HSP 90 in hybrid sturgeons Acipenser schrenckii ♀ 9 A. baerii ♂ exposed to ammonia-N stress. A 2 9 3 factorial experiment was arranged, in which each diet (0%, 1% AKG) was randomly assigned to 0.25 (control) 5 and 10 mg L À1 ammonia-N groups with three replicate aquaria for each 72 h. The 10 mg L À1 ammonia-N significantly increased serum ammonia concentrations and intestinal Gln concentrations and GS activity compared with the 0.25 or 5 mg L À1 ammonia-N groups. The intestinal Gln concentration and GS activity increased, and the serum ammonia concentration decreased, in fish given dietary supplementation of 1.0% AKG compared with fish given diets without AKG. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity in serum, gills and intestines decreased when fish were exposed to 5 or 10 mg L À1 ammonia-N, and their activity increased in fish given diets with 1% AKG. Catalase in the serum and gills decreased when fish were exposed to 5 or 10 mg L À1 ammonia-N and increased in fish given diets with 1% AKG. The 10 mg L À1 ammonia-N or 1% AKG supplementation increased HSP 70 and HSP 90 gene expression in the liver. The increased activity of antioxidant enzymes, and increased HSP 70 and HSP 90 gene expression in fish fed diets containing 1% AKG suggested higher tolerance to ammonia-N stress.

Effects of alpha-ketoglutarate on lifespan and functional aging of Drosophila melanogaster flies

“…These data suggest that the AKG-mediated stress response may involve the induction of specific stressprotective mechanisms, and the induction of HSP synthesis can be among them. In particular, AKG has been shown recently to increase expression of HSP70 and HSP90 genes in fish liver [18], that supports our results. Despite AKG induced oxidative stress in flies of both genders, lifespan extension was found only in AKG-fed females but not in males (Fig.…”

“…Since the importance of HSP90 function to the heat shock response in D. melanogaster has been clearly documented [17], higher level of HSP90 protein in AKG-fed females could contribute to the higher heat stress tolerance of these flies compared with control ones. In support of this, AKG was found recently to increase levels of heat shock proteins (HSP70 and HSP90) in fish [18].…”

The Antioxidative Function of Alpha-Ketoglutarate and Its Applications

“…Similarly, AKG also performs chemopreventive role in hepatocarcinogenesis induced by N-nitrosodiethylamine (NDEA) in rats by modulating the levels of antioxidants and lipid peroxide to access normal levels [ 21 ]. Furthermore, AKG shows high resistance to ammonia-N stress in hybrid sturgeons as it enhances antioxidant enzymes activity and HSP 70 and HSP 90 gene expression [ 22 ]. Besides, cyanide-induced oxidative stress could lead to neurotoxicity, the lipid peroxidation, and dysfunction of membrane especially in brain and kidney of animals like rats [ 23 ].…”

Age-related physiological and biochemical changes in Drosophila grown on alpha-ketoglutarate

“…Тому можна припустити, що у самців, вирощених на АКГ, спожитий АКГ швидко метаболізується і обробка мух токсикантами, після того як мухи припинили споживати АКГ, не дає очікуваного позитивного ефекту. Щодо теплового стресу, то нещодавно було показано, що АКГ може стимулювати синтез білків теплового стресу [25]. Припускаємо, що даний механізм може бути задіяний у підвищенні стійкості самців, вирощених на АКГ, до теплового стресу.…”

“…Разнообразные метаболические изменения, возникающие в процессе образования и развития опухоли, в большинстве случаев сопровождаются изменением спектра активности протеолитических ферментов: сериновых протеиназ [17,21], катепсинов [29, 24,25], металлопротеиназ [18,22], а также их эндогенных ингибиторов [27,23]. Агрессивность клеток новообразований различного гистогенеза и способность опухолей к метастазированию характеризуется повышением активности протеаз, активность которых регулируется специфическими эндогенными ингибиторами [28,30].…”