The Effect of Swimming Training on Spatial Memory and Reduction of Hippocampal Inflammation in Rats

The lifestyle in the machine world of the last century is low mobility and very little activity with the use of various types of equipment and facilities. This lifestyle is the basis of many physical and mental complications in today's humans and causes the occurrence of many chronic diseases such as diabetes and obesity, increased blood pressure, and metabolic syndrome as a whole, followed by widespread inflammation in the body. Increased inflammation in the body, especially in the central nervous system of the brain, can lead to neurological and behavioral disorders. The immune system plays an important role in regulating brain homeostasis. Even small amounts of Neuroinflammation can disrupt physiological processes that occur in the hippocampus, including neurogenesis. Inflammatory factors include inflammatory cytokines such as interleukin 6 and alpha necrosis factor. In recent years, human and animal studies have shown that the increase of these two cytokines in the body and brain can lead to a decrease in memory. However, its exact mechanisms are not fully understood. Recent findings also show that IL-6 is involved in cognitive functions and memory, and increasing its level in brain areas such as the hippocampus may lead to a decrease in memory, on the other hand, anti-inflammatory factors such as IL-10 (potential role in immunotherapy and prevention) And progress or recurrence of neuropathy play a role in the body. Interleukin 10 prevents the production and secretion of inflammatory cytokines. This cytokine is secreted to suppress pro-inflammatory effects in stressful situations. The most important brain region involved in cognitive functions and memory is the hippocampus. Any damage to nerve cells in this area of ​​the brain can be directly related to cognitive disorders. Exercise is known as a risk modulating factor for reducing memory and learning in neurological diseases and even Alzheimer's disease. It is assumed that neurological and vascular adaptation to exercise and physical activity improves cognitive function through neurogenesis, reducing pro-inflammatory processes and reducing cell damage. Physical activity can modulate microglial activation in the CNS. Low-intensity exercise is sufficient to induce an anti-microglial activation effect by regulating the expression of various factors. Some of these factors (eg, Myokines) can directly prevent microglial activation through various mechanisms that prevent Neuroinflammation in the CNS. Be secreted from different sources (such as damaged neurons, astrocytes, and microglia). According to past research and since the effect of swimming exercise on the amount of pro-inflammatory and inflammatory cytokines such as IL-6 and IL-10 and as a result on the amount of spatial memory in adult rats has not been investigated, this research was conducted in order to make its results for patients suffering from memory loss. It should be implemented in clinics as a suggested non-pharmacological and effective treatment, especially in elderly people who have been diagnosed with Alzheimer's disease.

C57BL6 male mice (approximate age 10-11 weeks) and (weight 18-21 grams) were obtained from Pasteur Institute of Iran and kept under light conditions of 12 hours of light and 12 hours of darkness (8 am to 8 pm) and a temperature of 1±23 degrees Celsius and humidity of 40-50% and enough water and food were freely available to them. The data were analyzed using t-test analysis and P<0.05 was considered significant. SPSS software was used for analysis and GraphPad Prism software (V8.5) was used for drawing graphs.

Mice who have experienced swimming showed a higher level of the cytokine interleukin 10 in their hippocampus compared to the control group (p=0.002) and the significant effect of swimming training on spatial memory was confirmed and swimming led to a decrease in hippocampal inflammation. Through the reduction of interleukin 6 levels compared to control group mice (p=0.025).

In this study, the effect of swimming training on the amount of inflammatory and anti-inflammatory factors and spatial memory was investigated, and according to the tests and results obtained, it was determined that swimming training has a significant effect on the reduction of the inflammatory factor interleukin-6 and the increase of the anti-inflammatory factor interleukin-10. It is effective in reducing the number of cognitive disorders, including spatial memory. Aerobic exercise can partially reverse the cognitive decline associated with diabetes by reducing the oxidative stress and inflammatory environment in the brain of T2D animals. Regular exercise has significant benefits on insulin sensitivity in adults with type 2 diabetes and may persist for more than 72 hours after the last exercise session. Long-term intense exercise can generally lead to higher levels of inflammatory mediators and thus may increase the risk of injury and chronic inflammation. In contrast, moderate exercise or vigorous exercise with adequate rest periods can achieve maximum benefit. Exercise can protect against age-related cognitive decline, Alzheimer's disease (AD), and vascular dementia. We provide evidence of swimming exercise in other animal models that assess cognitive functions and hippocampal inflammatory and Neurotrophic systems. In support of our data, studies are showing that swimming exercise can improve cognitive deficits in various animal models. Regular swimming exercise in mice significantly increases working, spatial and cognitive memory in Alzheimer's disease conditions or is effective in healthy conditions as well. Overall, this study shows that swimming exercise may be suggested as a complementary non-pharmacological strategy for the treatment of cognitive decline in affected individuals. However, further studies should focus on training protocols that can be used in humans.