The low-frequency pulsed electromagnetic fields (PEMF) did not affect the apoptotic rate but significantly increased the proliferation. Apoptosis level in patellar tendon fibroblasts in the scrape wound after 1 week (B). Apoptosis was measured using Annexin V-FITC and PI staining by flow cytometry. Proliferation measured using BrdU incorporation into patellar tendon fibroblasts in the scrape wound after 1 week (A). One part of the cells was treated with the low-frequency PEMF generated by the Somagen™ device applying the ‘wound healing’ program. Nontreated cells served as negative control. Mean ± SD, ***P <0.001, (N = 5, n = 2) are indicated.