Anti-hyperplastic effects of the (Burseraceae) leaves aqueous extract on tamoxifen-induced endometrium hyperplasia on Wistar rat.

Objectives: Combining tamoxifen, the most common breast cancer hormonal therapy, with natural antitumor substances may prevent its hyperplastic effects on the uterine endometrium. () is traditionally recommended for the treatment of cancerous diseases. To investigate its antiproliferative properties, the present study was designed to assess the ability of the combined administration of tamoxifen with the aqueous extract of leaves to inhibit the trophic effect of this hormone therapy on rat uterine endometrium without compromising its non-proliferative effect on breast tissue.

Methods: Ovariectomized (OVX) female rats were simultaneously treated with tamoxifen (10 mg/kg) intraperitoneally and leaves (at doses of 25, 50 and 100 mg/kgBW) by gavage. Control groups received either distilled water or tamoxifen alone. Treatments lasted 37 days. The 38th day, animals were sacrificed under anesthesia (diazepam: 10 mg/kgBW and ketamine: 50 mg/kgBW). The relative uterine weight was determined and the histological analysis of the uterus and mammary gland was performed. The oxidative status of the uterus was assessed and the levels of cholesterol and estradiol were evaluated in serum and uterus.

Results: Tamoxifen increased uterine weight and induced endometrial hyperplasia. This effect was associated with increased uterine levels of cholesterol (164.22%; p < 0.001), estradiol (927.5%; p < 0.001) and malondiadehyde (86%; p < 0.05), but unchanged antioxidant enzymes activities. The administration of leaves unchanged tamoxifen-increased uterine weight but reduced uterine epithelium hypertrophy (56.4%; p < 0.01). also increased uterine levels of malondiadehyde and antioxidant enzymes. The levels of estradiol and cholesterol in the uterus decreased while no changes were observed in the mammary gland of animals treated with tamoxifen alone or in co-administration with .

Conclusions: has antiproliferative properties and could complement endocrine therapy of estrogen-dependent breast cancer.