Low-Intensity Pulsed Ultrasound Relieves Mild and Severe Myelosuppression Induced by Cyclophosphamide in Rabbits

This study aimed to investigate the effect of low-intensity pulsed ultrasound (LIPUS) on cyclophosphamide (CTX)-induced rabbit myelosuppression.

Rabbits (n = 90) were randomly divided into a mild myelosuppression group (n = 40), a severe myelosuppression group (n = 40), and a normal control group (group Cu₂₈ ; n = 10). The mild and severe myelosuppression models were established by daily ear vein injection of 15- and 40-mg/kg CTX for 4 continuous days, respectively. Then they were randomly divided into LIPUS groups (A_u and B_u ) and control groups (A_c and B_c ). LIPUS was applied once per day for 20 minutes for 7 (A_u7 and B_u7 ) and 28 (A_u28 and B_u28 ) days. Physical conditions, mortality, blood cell counts, and bone marrow proliferation were calculated. Erythropoietin interleukin 3, and granulocyte-macrophage colony-stimulating factor levels were measured by an enzyme-linked immunosorbent assay. Flow cytometry was used to detect the granulocyte phagocytosis rate. Hematoxylin-eosin staining was performed to analyze changes of skin and muscle.

Compared with the control group, LIPUS improved the number of peripheral blood cells (P < .05) and bone marrow nucleated cells and reduced the mortality of rabbits with myelosuppression of different degrees. Long-term treatment for 28 days had no effect on the levels of erythropoietin, interleukin 3, and granulocyte-macrophage colony-stimulating factor and granulocyte phagocytosis (P > .05). The parts of the skin where LIPUS was applied did not show any burning marks, and the muscle tissue in the path of LIPUS acoustic channels showed no obvious pathologic changes.

Low-intensity pulsed ultrasound is a safe and effective method to relieve CTX-induced myelosuppression.