Treatment Effect of Low-Intensity Pulsed Ultrasound on Benzene- and Cyclophosphamide-Induced Aplastic Anemia in Rabbits.

Background. Transplantation and immunosuppressive therapies are the available treatments for aplastic anemia; however, each strategy has its advantages and disadvantages. Objective. The aim of this study was to find a new strategy for aplastic anemia treatment. Design. This was an experimental and comparative study. Methods. The aplastic anemia model was established by injecting rabbits with benzene and cyclophosphamide. The rabbits with aplastic anemia were divided into low-intensity pulsed ultrasound (LIPUS) and control groups. The distal femoral metaphysis of rabbits in the LIPUS group was treated with ultrasound for 30 days (20 min/d), whereas the control group received a sham treatment. Diarrhea, mortality, and blood cell count were evaluated. The levels of forkhead box P3, interleukin 17, interleukin 4, and interferon gamma were measured using an enzyme-linked immunosorbent assay. Bone marrow hyperplasia was observed by hematoxylin-eosin staining and scanning electron microscopy. Results. The numbers of red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs) were lower, the amount of hematopoietic tissue was lower, and the amount of adipose tissue was higher in the rabbit aplastic anemia model than in the normal rabbits. The numbers of RBCs, WBCs, and PLTs increased after LIPUS treatment. The interleukin 17 level decreased, whereas the forkhead box P3 level increased. The amount of hematopoietic tissue increased, whereas the amount of adipose tissue decreased. Limitations. The number of hematopoietic stem cells could not be evaluated. Conclusions. LIPUS improved the hematopoietic microenvironment, accelerated the reconstruction of bone marrow cells, and increased the quantity and quality of RBCs, WBCs, and PLTs in the peripheral blood. Hence, it can serve as a novel treatment strategy for aplastic anemia in the future.