Exercise therapy plays key roles in functional improvements during neurorehabilitation. However, it may be difficult for some people to properly perform exercise because mobility and endurance might be restricted by neurological deficits due to stroke. Additionally, there is little evidence detailing the biological mechanisms underlying the most effective swimming exercise protocols for neuroplasticity after stroke. Thus, the present study investigated the effects of swimming exercise on neuroplasticity in a cerebral infarction rat model according to the timing and intensity of exercise. A total of 45 male Sprague-Dawley rats (300 ± 50 g, 10 weeks old) were subjected to photothrombotic cerebral infarction and randomly divided into five groups: non-exercise (group A, n = 9); early submaximal (group B, n = 9); early maximal (group C, n = 9); late submaximal (group D, n = 9); and late maximal (group E, n = 9). Swimming exercise was performed five times a week for 4 weeks, and cognition was evaluated with the Morris water maze (MWM) test. Assessments of superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels and immunohistochemical analyses of brain-derived neurotrophic factor (BDNF) were conducted in the ipsilesional hippocampus region. After 4 weeks of exercise, the escape latency was shorter and velocity was greater in group B than in groups A, C, D, and E (p = 0.046, p <  0.001, respectively). Furthermore, SOD activity was higher and MDA levels were lower in group B than in groups A, C, D, and E (p = 0.004, p = 0.019). The immunohistochemistry results revealed that the greatest BDNF immunoreactivity was in group B. Taken together, these results indicate that early submaximal swimming exercise may be the most effective protocol for the recovery of neurological deficits in a rat model of cerebral infarction.

中文翻译：

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运动时间和强度对脑梗死大鼠模型神经可塑性的影响。

运动疗法在神经康复期间的功能改善中起着关键作用。然而，由于中风导致的神经功能缺陷可能会限制一些人的活动能力和耐力，因此某些人可能难以正确进行锻炼。此外，几乎没有证据详细说明中风后神经可塑性最有效的游泳锻炼方案背后的生物学机制。因此，本研究根据运动的时间和强度研究了游泳运动对脑梗塞大鼠模型神经可塑性的影响。共 45 只雄性 Sprague-Dawley 大鼠（300±50 g，10 周龄）进行光血栓性脑梗死，随机分为 5 组：非运动组（A 组，n = 9）；早期次极值（B 组，n = 9）；早期最大值（C组，n = 9）；晚期次极值（D组，n = 9）；和晚期最大值（E组，n = 9）。每周进行 5 次游泳运动，持续 4 周，并通过莫里斯水迷宫 (MWM) 测试评估认知能力。在同侧海马区进行了超氧化物歧化酶 (SOD) 活性和丙二醛 (MDA) 水平的评估以及脑源性神经营养因子 (BDNF) 的免疫组织化学分析。运动 4 周后，与 A、C、D 和 E 组相比，B 组的逃逸潜伏期更短，速度更快（分别为 p = 0.046，p < 0.001）。此外，与 A、C、D 和 E 组相比，B 组的 SOD 活性更高，MDA 水平更低（p = 0.004，p = 0.019）。免疫组化结果显示BDNF免疫反应最大的是B组。