Effects of silymarin, cabergoline and letrozole on rat model of endometriosis.

OBJECTIVE: Silymarin as an herbal drug has potent antioxidant effects that could make it a good choice for endometriosis therapy. The aim of the current study was to determine the effects of silymarin as an herbal drug on induced endometrial lesion in rat model of endometriosis.

MATERIALS AND METHODS: A total of 32 mature, female Sprague-Dawley rats were allocated into 4 experimental groups. The duration of study was about 6 months. Endometriosis implants were surgically prepared and autografted into 32 rats. Three weeks after endometriosis induction, animals were randomly allocated into four groups: Group 1 received cabergoline (CAB group); Group 2 received letrozole (LET group); Group 3 received silymarin (SIL group) and Group 4 received no medication (CONT group). Experimental groups were treated for 3 weeks and then were sacrificed for volume and histopathological evaluation of implants and biochemical assessment. Serum and peritoneal levels of vascular endothelial growth factor (VEGF), total antioxidant activity (TAC) and tumor necrosis (TNF)-α were measured.

RESULTS: Mean volume of the implants decreased significantly in silymarin (p < 0.001), letrozole (p < 0.001) and cabergoline (p < 0.001) groups compared to the control. Histopathologic score was significantly lower in silymarin (p: 0.039), letrozole (p: 0.017) and cabergoline (p < 0.001) groups compared to the control. Those receiving silymarin had significantly higher serum TAC compared to control after 21 days of therapy (p < 0.001).

CONCLUSION: Silymarin, Letrozole, and Cabergoline administration resulted in decreased size and histopathologic grade of the induced endometrial lesions in a rat model. Silymarin appears to be a virtual novel therapeutic agent for treatment of endometriosis.