Research question
Can cannabidiol (CBD) be used in the treatment of endometriosis for its anti-inflammatory, antioxidative and antiangiogenic effects?

Design
Endometrial implants were surgically induced in 36 female Wistar albino rats. After confirmation of endometriotic foci, the rats were randomized into four groups. In the leuprolide acetate group, rats were given a single 1 mg/kg s.c. leuprolide acetate injection. The other groups were 5 mg/kg CBD (CBD5), saline solution and 20 mg/kg CBD (CBD20); daily i.p. injections were administered for 7 days. After 21 days, the rats were euthanised, and total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) measurements in blood and peritoneal fluid samples, and immunohistochemical staining for TNF-α, IL-6 and vascular endothelial growth factor (VEGF) of endometriotic tissues were evaluated.

Results
Significant reductions in the endometriotic implant surface area (P = 0.0213), serum TOS (P = 0.0491), OSI (P = 0.0056), IL-6 (P = 0.0236), TNF-α (P = 0.0083) and peritoneal fluid OSI (P = 0.0401), IL-6 (P = 0.0205) and TNF-α (P = 0.0045) concentrations were observed in the CBD5 group when compared with the saline solution group. Compared with the saline solution group, increased TAS concentrations in serum (P = 0.0012) and peritoneal fluid (P = 0.0145) were found in the CBD5 group. The CBD5 and leuprolide acetate groups were similar regarding inflammatory and oxidative stress parameters of serum and peritoneal fluid samples. The CBD5 group showed significantly lower mean intensity in both surface epithelium and stromal cells for VEGF (both P = 0.002) and only in surface epithelium cells for IL-6 (P = 0.0108), when compared with the leuprolide acetate group.

Conclusion
Due to its anti-inflammatory, antioxidative and antiangiogenic effects, CBD might be a therapeutic agent candidate for endometriosis.