Primary and secondary thrombocytosis induced by exercise and environmental luminosity

We investigated the exercise and different environmental luminosities effects on blood platelets count in order to identify primary and secondary thrombocytosis, respectively.

Platelets alteration has been associated with important pathological events, such as neurodegenerative diseases, and the count of these cells in bloodstream is influenced by several effects, including physical and chemical. Owing the difficulty to study the aetiology of thrombocytosis in human models, we employed acute and chronic free drug interventions in order to identify these two types of this important disease in laboratory animals.

Forty rats were exposed to standard (SI) or experimental (EI) illumination from 45 days-old. Both groups were exposed to 12 h daylight (2700 K; 565-590 nm; < 60 lux; from 06:00 h to 18:00 h). During dark period SI animals were kept in total darkness while EI remained under red light (> 600 nm, < 15 lux). At 92 days-old, exercised animals were submitted to an acute bout of swimming at individualized intensity and control animals remained at rest.

Blood samples were collected immediately after the exercise for platelets count, which were among 849000 ± 115817 and 1085600 ± 177089/mm³ of blood. Exercise (F = 6.91; p = 0.01) and EI (F = 6.66; p = 0.01) increased platelets count, showing no interaction between effects (F = 0.01; p = 0.89).

Primary thrombocytosis was detected owing an acute exercise and the secondary thrombocytosis due to the constant red light during dark period, without any pharmacological interventions and strongly respecting the ethical aspects, enabling future studies on aetiology of thrombocytosis through this model (Fig. 2, Ref. 35).