Vascular endothelial growth factor receptor-2 inhibitor cediranib causes regression of endometriotic lesions in a rat model

Vascular endothelial growth factor (VEGF) receptor-2 plays an essential role in angiogenesis, and it also expressed in the glandular epithelium and stromal cells of ectopic endometrium. Cediranib is a protein tyrosine kinase inhibitor that potently inhibits VEGF receptor-2, but there is no study about its effects on the endometriosis. We induced endometriosis on both sides of the abdominal wall in 20 female Sprague-Dawley rats and randomly divided them into 2 groups. They were administered: cediranib 4 mg/kg/day (group 1), equal saline (group 2) for 12 days. Then, the lesion volumes were calculated, and Masson trichrome was used to detect fibrosis. Angiogenesis was evaluated by CD-31 immunohistochemistry and serum VEGF levels. Proliferation was indicated by proliferating cell nuclear antigen immunohistochemistry. Apoptosis was measured by a TUNEL assay and cleaved caspase-3 immunohistochemistry. In the treatment group, the lesion volumes were smaller (P < 0.05), and the degree of fibrosis was greater. The microvessel density was lower (P < 0.05) than control, however, serum VEGF was up-regulated by a negative feedback mechanism (P < 0.01). In addition, proliferation was significantly suppressed (P < 0.01), and apoptosis in the lesions was more obvious in the treatment group. These data indicated that cediranib can inhibit development of endometriotic lesions in rats.