Effects of α-ketoglutarate on muscle energy metabolism in weanling pigs chronically challenged with lipopolysaccharide | α-酮戊二酸对脂多糖刺激断奶仔猪肌肉能量代谢的影响

Chinese. 【目的】研究α-酮戊二酸(AKG)对经脂多糖(LPS)多次刺激后断奶仔猪肌肉能量代谢的影响及其分子机制。【方法】采用2×2因子试验设计,LPS刺激(有、无)和AKG添加量(0、1%)为2个主效应,共4个处理组。选取24头(6.79±0.32)kg的断奶仔猪(杜洛克×长白×大白),随机分配到4个处理组,每个处理设6个重复(猪)。LPS刺激组仔猪在试验的第10、13和15 天腹腔注射100 μg?kg-1 BW LPS,无LPS刺激组注射等量的生理盐水。第16 天仔猪麻醉后进行屠宰,取腓肠肌样品,反相高效液相色谱法检测腓肠肌细胞内腺苷酸水平,Western blotting检测腓肠肌AMP激活蛋白激酶(AMPK)和乙酰CoA羧化酶(ACC)表达及其磷酸化。【结果】()日粮添加1%AKG和LPS刺激对仔猪腓肠肌AMP含量和AMP/ATP的影响存在交互作用(P＜0.05)。仔猪日粮中添加1% AKG能显著提高腓肠肌ADP水平(P＜0.05),缓解了LPS刺激引起的AMP水平和AMP/ATP升高、ADP和能荷(EC)降低(P＜0.05)。(2)LPS刺激和日粮中添加AKG对AMPK表达量和AMPK磷酸化水平(pAMPK/AMPK)均无影响。(3)日粮中添加1% AKG抑制了ACC的磷酸化;LPS刺激使ACC表达量升高(P＜0.05),并促进ACC磷酸化(P＜0.05)。【结论】LPS刺激增加肌肉能量损耗,日粮中添加1% AKG有利于肌肉维持正常的能量代谢;日粮添加AKG通过调控ACC的活性与表达影响肌肉能量代谢;AKG可能通过ACC信号影响肌肉能量代谢,进而改善LPS刺激下机体能量代谢状态。

English. 【Objective】 The aim of the current study was to evaluate the effects of dietary supplementation with α-ketoglutarate (AKG) on muscle energy metabolism with reference to its molecular mechanism in weaned pigs after repetitive stimulation with lipopolysaccharide (LPS). 【Method】 Twenty-four piglets were assigned to a 2×2 factorial arrangements with LPS challenge (or without) and dietary supplementation of AKG at 0 and 1% as the main factors, total four treatments. The 24 weaned piglets (Duroc×Landrace×Yorkshire, 6.79±0.32 kg BW) were randomly allocated to one of the 4 treatment groups (6 replicates for each group). LPS challenged piglets were given a single intraperitoneal injection of LPS at 10, 13, 15 d and non-challenged piglets were injected intraperitoneally with physiological saline at the same doses. On 16 d, all pigs were killed and anesthesia and gastrocnemius tissues were excised. Muscle adenine nucleotide was assayed by HPLC, western blot assays were performed for muscle AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) expression and their phosphorylation. 【Result】 There were significantly interaction effects of AKG supplementation and LPS challenge on AMP level and AMP/ATP ratio (P0.05). Dietary supplementation of 1% AKG increased ADP (P0.05), attenuated the increase of AMP level and AMP/ATP and the decrease of ADP and energy charge (EC) induced by LPS challenge (P0.05). AKG supplementation and LPS challenge had no effects on the expression and phosphorylation of AMPK. Dietary supplementation of 1% AKG significantly inhibited ACC phosphorylation. LPS challenge significantly increased the expression and phosphorylation of ACC (P0.05). 【Conclusion】These results demonstrated that, under the present experimental conditions, LPS challenge resulted in muscle energy depletion. Dietary supplementation of 1% AKG could maintain muscle energy metabolism. Dietary supplementation of 1% AKG might affect muscle energy metabolism via ACC signaling. AKG might affect muscle energy metabolism via ACC signaling, therefore improve body energy status after LPS challenge.