高脂肪食誘発肥満成長マウスにおける認知機能低下に対する異なる有酸素運動強度の予防効果

Preventive Effects of Different Aerobic Exercise Intensities on the Decline of Cognitive Function in High-Fat Diet-Induced Obese Growing Mice.

• Ju Yong Bae

抄録

本研究の目的は、成長期のマウスにおける高脂肪食誘発性肥満に伴う認知機能および脂肪分解の低下を予防するために、異なる運動強度の効果を明らかにすることであった。 40匹の雄性C57BL/6マウス（4週齢）を、通常食（CO、＝10）群と高脂肪食（HF、＝30）群に分け、8週間の肥満誘導を行った。その後、HF群をHF、HF＋低強度トレーニング（HFLT）群、HF＋高強度トレーニング（HFHT）群に等分し、マウスにトレッドミルトレーニングを8週間実施した。 8週間のトレーニング介入後、体重と脂肪量はトレーニング群の方がHF群よりも有意に低かった（＜0.05）。脂肪トリグリセリドリパーゼ（ATGL）、ホルモン感受性リパーゼ（HSL）、モノグリセリドリパーゼのレベルは、HF群よりもトレーニング群の方が有意に高く（<0.05）、ATGLとHSLのレベルはHFHT群の方がHFLT群よりも有意に高かった（<0.05）。Y-maze検定では、訓練群はHF群に比べて総項目数と交替率が高かった( < 0.05)。海馬神経成長因子、脳由来神経栄養因子、ニューロトロフィン-3のレベルは、トレーニング群の方がHF群よりも有意に高かった( <0.05)。しかし、運動強度による群間の有意差は認められなかった。 以上の結果から、低強度の運動は高強度の運動と同等に認知機能の低下や脂肪分解の予防に効果があり、期待される作業効率や副作用の予防という点でははるかに効果的であることが示唆されました。

The purpose of this study was to elucidate the effects of different exercise intensities in preventing the decline of cognitive function and lipolysis associated with a high-fat diet-induced obesity in growing mice. Forty male C57BL/6 mice, aged 4 weeks, were divided into the normal diet (CO, = 10) and high-fat diet (HF, = 30) groups to induce obesity for 8 weeks. Subsequently, the HF group was subdivided equally into the HF, HF + low-intensity training (HFLT), and HF + high-intensity training (HFHT) groups, and mice were subjected to treadmill training for 8 weeks. Following the 8-week training intervention, body weight and fat mass were significantly lower in the training groups than in the HF group ( < 0.05). Adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase levels were significantly higher in the training groups than in the HF group ( < 0.05), and the ATGL and HSL levels were significantly higher in the HFHT group than in the HFLT group ( < 0.05). The Y-maze test showed that the training groups had a higher number of total entries and percent alternation than the HF group ( < 0.05). Hippocampal nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 levels were significantly higher in the training group than in the HF group ( < 0.05). However, there was no significant difference according to the exercise intensity among the groups. The results of this study suggested that low-intensity exercise is as effective as a high-intensity exercise in preventing the decline of cognitive function and lipolysis, and far more effective in terms of an expected efficiency of workload and prevention of side effects.