Blood flow restriction training before platelet-rich plasma preparation induces a significant reduction in its...

To assess platelet-rich plasma (PRP) changes in platelet and leucocyte count, insulin-like growth factor (IGF-1) and interleukin 6 (IL-6) concentration after bilateral low-load knee extensions with blood flow restriction (BFR).

A randomised controlled trial involving two groups was conducted. The intervention group underwent low-load bilateral knee extensions with BFR, while the control group without BFR. Inclusion criteria were (1) male individuals, (2) between 18 and 40 years, (3) with Tegner activity level ≥5 and (4) no musculoskeletal conditions that would interfere with exercise. The participant performed a standard protocol of 30-15-15-15 repetitions of consecutive sets with 30-s rest intervals at 80% of limb occlusive pressure and a 15-lb load. PRP platelet and leucocyte count, IGF-1 and IL-6 concentration measurements (via flow cytometry, chemiluminescence testing and immunochromatography, respectively) were conducted before exercise and 10, 20 and 30 min after the intervention (T1, T2, T3 and T4, respectively).

A total of 24 participants were enrolled and allocated into two groups. The exercise bout in the BFR group resulted in higher platelet concentration and dose at T2 and T3, reaching a mean 9.9% maximum concentration increase and a mean 15.6% maximum dose increase at T2 (p = 0.07). Similarly, leucocyte concentrations and dose presented a steep decrease at T2, representing a 17.8% and 16.8% decrease, respectively. Moreover, a peak increase in IGF-1 concentration of 4.1% above baseline was observed at T3. IL-6 concentrations were significantly lower at all time points in the BFR group (˂1 pg/mL, p = 0.01).

Low-load bilateral knee extensions with BFR induced a significant reduction of IL-6 concentration in PRP, which holds potential to tailor treatment for specific musculoskeletal injuries.

Level I.