# Dynamic Correlation between Platelet Aggregation and Inflammatory-like State in Athlete Horses
## 4 Discussion  
The innate immune system elicits certain key and prompt responses to defend the body against infection, inflammation, tissue injury and stress from exercise [13]. These systemically activated and complex early defensive responses, termed acute-phase responses, are promoted by APPs, which are serum components, produced primarily by hepatocytes [22; 23]. The serum concentration of positive APPs, mainly included in the \(\alpha\)-globulin fraction, markedly increases following inflammation [22], whereas the serum values of negative APPs, such as albumin, decrease in response to inflammation as well as stress [23]. Many researchers revealed the influence of these proteins on human and animal physiology, resulting in them being termed \"molecular thermometers\" [22; 23; 24; 25]. Recent studies carried out on animals pointed out the sensitivity of different APPs, suggesting them as strong markers of herd health in large animals and proposing them as optimum markers of stress conditions [25; 26; 27]. The results gathered in the current study showed a significant effect of exercise on all investigated parameters with the exception of serum total proteins, \(\gamma\)-globulins, A/G ratio and slope values. The concentrations of all the investigated parameters fall within the physiological range proposed for the equine species and are in agreement with the findings reported in a previous investigation carried out on athletic horses [19]. The analysis of protein electrophoretograms obtained from serum samples of horses after exercise showed a remodeling of the different factions within the protein pool. As a matter of fact, though the concentration of total proteins did not undergo a significant variation during the experimental period, albumin and \(\alpha\)1-, \(\alpha\)2-, \(\beta\)1- and \(\beta\)2-globulin fractions increased after exercise while albumin showed an opposite trend. Albumin is known as a negative APP, whereas the \(\alpha\)- and \(\beta\)-globulin fractions are known to include both positive and negative APPs including haptoglobin, C-reactive protein, serum amyloid A, ceruoplasmin, fibrinogen, alpha 1-acid glycoprotein, complement proteins and transferrin. According to the results gathered in the current study, the CRP also showed increased serum values after exercise. In the context of exercise, increases in CRP concentrations have been shown in sled dogs [28; 29] and in humans after exhausting exercise, but not in typical training [30; 31], whereas any change in CRP values has been found after limited- and long-distance endurance rides in horse [32]. In agreement with previous findings [12], the results gathered in the present study suggest that jumping exercise induces an inflammation-like state, reinforcing the supposition that this kind of exercise reflects a classical APR in athletic horse. It is well known that the APR, in addition to its important functions to fight bacterial and viral infections, also stimulates clearance of injured tissue, setting the stage for tissue restoration and growth [33]. These latter activities might theologically explain why an APR is initiated by exercise. Regarding the mechanism orchestrating the activation of APR following exercise, it is widely accepted that intense physical activity is able to induce this response through the induction of interleukin-6 [3; 34]. Together with the increase in pro-inflammatory interleukins, exercise also leads to an augmentation of several anti-inflammatory mediators, such as II-1 receptor antagonist [13; 35]. Thus, during physical exercise, it seems like a parallel \"protective\" anti-inflammatory counter-regulation occurs within the APR. It has been proposed that exercise-induced muscle injury was the primary stimulus for the release of IL-6 and the cascade reactions that this interleukin entails. It has been assumed that the signals generated by muscles during exercise lead to IL-6 release regardless of the presence of muscle damage [36].