# Effect of Moderate-Intensity Endurance Exercise on Inflammatory Cytokines in Leukocytes of Dogs
## 4 Discussion  
The purpose of this study was to investigate the effect of short-term endurance exercise on hematological variables and cytokine regulation in healthy dogs. We found positive  
Figure 3: Comparison of changes in anti-inflammatory cytokines according to the duration of the exercise period. * Denotes statistically significant comparison (\(p<0.05\)) between groups at that time point. (A,B) superscripts denote statistically significant values between pre-exercise, two weeks of exercise, and post-exercise for the exercise group (\(p<0.05\)). Figure 2: Comparison of changes in pro-inflammatory cytokines according to the duration of exercise. * Denotes a statistically significant comparison (\(p<0.05\)) between groups at that time point. (a,b) superscripts denote statistically significant comparisons between pre-exercise, two weeks of exercise, and post-exercise for the control group (\(p<0.05\)). (A–C) superscripts denote statistically significant values between pre-exercise, two weeks of exercise, and post-exercise for the exercise group (\(p<0.05\)). changes in WBC, AST, ALP (Table 4), and glucose following moderate-intensity endurance exercise and significant changes in pro-inflammatory cytokines, including TNF-\(\alpha\), IFN-\(\gamma\), and IL-1\(\beta\), and anti-inflammatory cytokine IL-4 (Figures 2 and 3). To the best of our knowledge, this is the first study to confirm the proper regulation of cytokines through exercise in healthy dogs, suggesting that WBC may be involved in the primary mechanism by which exercise-induced cytokines are regulated. Adequate adaptation to the experimental environment and exercise program is required, as dogs may show resistance to standing on the treadmill and exercise or may be easily distracted by their sense of smell and hearing [28]. The current study provided the beagles sufficient time to adapt to the experiment and adequate compensation (walking, play, communion, etc.). No dogs experienced any side effects or maladaptive behavior following exercise, and there were no abnormal findings in the health checkup conducted by the veterinarian. Hematological and serum biochemical analysis is an effective method that evaluates physiological changes and health abnormalities in dogs who have exercised [29; 30; 31]. Elevated WBC count is used as a risk indicator for cardiovascular disease, inflammation, and excessive physical and psychological stress [32; 33; 34; 35]. In this study, dogs who exercised for a total of four weeks showed a significant decrease in WBC count at the second week of exercise but returned to pre-exercise levels after completing the exercise program. Exercise in the early stages of training causes mild oxidative stress and increases cell damage and inflammation [36; 37], but continuous training effectively improves anti-inflammatory and antioxidant capacity [36; 38]. Accordingly, these changes in WBC count are considered to appropriately represent the adaptation of exercise. Long-term and high-intensity exercise is known to induce a decrease in WBC count in humans [39], and our study found that moderate-intensity exercise for four weeks also reduces WBC count in dogs. Through this, the exercise program conducted in this study is considered to have sufficient intensity and duration to positively change canine WBC count. [PERSON] et al. [40] reported a significant positive correlation between endurance exercise and WBC reduction. Neutrophphils contribute phagocytosis to the inflammatory response, which, for exercise, occurs following repeated eccentric contractions that cause local muscle damage and release of chemokines and cytokines [41; 42]. Neutrophphils are produced in the bone marrow from the myeloid cell line [43] and are the major subset of the polymorphonuclear phagocytes, representing 50-75% of total circulating leukocytes [44]. Furthermore, neutrophils play a central role in infection, genetic disorders, inflammation, and innate immune function [45; 46].