The Effects of Two Models of Training with Different Days of Rest-to-Training Ratios and Natural Honey Supplementation on Serum Concentration of Interleukin-6 and its Hippocampal Gene Expression in Male Immature Rats

This study was designed to investigate the effects of two models of training with different days of rest-to-training ratios of high-intensity interval training (HIIT) and natural honey supplementation on serum interleukin-6 (IL-6) and its expression in the hippocampus of immature Wistar rats. Thirty-six male rats were randomly assigned into six groups: control; honey (10% in drinking water); 4-day strenuous interval training; 4-day strenuous interval training+honey; 7-day strenuous interval training; and 7-day strenuous interval training+honey. They underwent HIIT (from 10-16 m/min in the first week to 36-40 in the last week) during 4-day (three days training, one day rest) and 7-day (six days training, one day rest) models for a month. Results demonstrated that the serum concentration of IL-6 was significantly (P=0.001) higher in the 7-day program in comparison with the control group.  Supplementation with honey in the 7-day group resulted in a lower level of serum IL-6 compared with 7-day group alone (P=0.018). There was no significant difference between four days and control groups (P=0.946). Both 7-day (P=0.007) and 4-day (P=0.005) training programs lead to a significantly higher level of gene expression of IL-6 in the hippocampus. However, honey supplementation didn’t modulate hippocampal gene expression in 4-day-honey (P=0.983) and 7-day-honey groups (P=0.583). Therefore, HIIT increases hippocampal gene expression of IL-6; however, longer period of training cause increase systemic inflammatory cytokines. Although honey supplementation couldn't adjust the central effect of the intensive interval training, it can ameliorate systemic inflammation. Also, honey hasn't anti-inflammatory effect in non-training and non-inflammatory conditions.