The Effects of High-Intensity Interval Training with Supplementation of Flaxseed Oil on BDNF mRNA Expression and Pain Feeling in Male Rats

Background. It seems that based on the independent effects of physical activity and flax oil on pain, it is possible the interactions of these two effects reduces or mitigate the impact of pain or strengthen it. Objectives. This study investigates the effect of high-intensity interval training (HIIT) and flaxseed oil supplementation on hippocampal BDNF expression and pain feeling in male rats. Methods. Twenty adult Wistar rats were randomly divided into four groups (five in each group) including control-saline (CS), training-saline (TS), control-flaxseed oil (CO), and training-flaxseed oil (TO). The training groups were given HIIT program (10 weeks, five sessions in week) on a rodent treadmill at 90–95% of VO2 max and supplement groups also received flaxseed oil (100 mg/kg per cage). Pain threshold was assessed by the hot plate test at a temperature of 55 ± 0.5 °C five days after the last session training. Then rats were sacrificed, their hippocamp tissue frizzed, and sent to laboratory to determine the BDNF gene expression. Results. The results showed that training significantly induced higher hippocampal BDNF mRNA expression (P=0.001) and lower pain threshold (P=0.02). Training-flaxseed oil combination group induced significant increase in BDNF expression (P=0.04). There were no significant differences between the other groups. Conclusion. The present study showed the useful role of flaxseed oil supplement and HIIT program in increasing an important factor for Alzheimer's disease (BDNF gene). It also showed that, although HIIT may be accompanied with reduced pain threshold and increased pain feeling, it has beneficial effects on memory enhancement gene (BDNF).