Background: Ploy cystic ovary syndrome (PCOS) is a common gynecological disorder affecting between 4-20% of females worldwide. Curcumin, the active ingredient in turmeric (Curcuma longa Zingiberaceae) is a yellow polyphenol with a wide range of pharmacological activities such as antioxidant, anti-inflammatory, anti-tumor, neuroprotective and cardioprotective properties. 

Methods: Letrozole was used to induce PCOS in female Wistar rats. Curcumin, metformin, or a combination of both was given to assess their therapeutic effects. Body weight, estrogen, progesterone, testosterone, and glucose levels were measured after disease induction and at the conclusion of treatment. Additionally ovarian histomorphology was examined after sacrificing the animals and removal of the ovaries.

Results and conclusion: Weight was significantly reduced in the curcumin, metformin and curcumin and metformin combination groups. Testosterone was decreased, progesterone was increased, and normal ovarian morphology was restored in the three groups. In Conclusions curcumin is therapeutically effective for PCOS and is comparable to metformin.

Study design

PCOS Induction

Six weeks old female rats were randomly divided into five groups; group one (n=17), served as control group, received 2 ml/kg of 1% CMC solution via oral gavage. Groups two to five (n=16 each); treatment groups, received 1mg/kg of letrozole dissolved in 1% CMC solution (2ml/kg) via oral gavage daily for 21 days (Kafali et al. 2004).

PCOS Treatment

After PCOS induction using letrozole, animals in groups two to five received treatment for a period of 20 days as follows; group 2 received metformin solution 500 mg/kg via oral gavage, group 3 received 100mg/kg curcumin dissolved in olive oil as oral drops, group 4 received a combination of 100 mg/kg curcumin oral drops and 500 mg/kg metformin oral gavage, while group 5 served as control group, received 2ml/kg olive oil oral drops.

The doses of metformin (Lemos et al. 2014), and curcumin (Nonose et al. 2014) were used based on previous studies.

Biochemical analysis

Body weight was measured every three days until the age of six weeks and daily thereafter.

A tail vein blood sample was withdrawn from each rat into a clot activating gel tube. The samples were left for 10 minutes to clot and then centrifuged for 10 minutes at a speed of 5000 rpm. Serum was poured into Eppendorf tubes and freezed at -60 C˚ for enzyme-linked immunosorbent assay (ELISA) hormonal analysis. Glucose was also measured after overnight fasting using a simple glucocheck device. Overnight fasting glucose was measured twice; once after PCOS induction and another after conclusion of treatment using a commercial glucocheck device (Mayyas et al. 2015).

Animals, at end of experiments, were anesthetized using 20mg/kg of thiopental intraperitoneal injection 3 minutes before sacrificing. After scarification truncal blood was collected in clot activating gel tubes, kept for 10 min to clot and then centrifuged for 10 min at 5000rpm speed. Serum was poured into Eppendorf tubes and freezed at -60 C˚ for hormonal assay. Serum samples were thawed at cool room temperature for over one hour. Then the tests were done according to the manufacturer’s instructions. Absorbance was read using Apoch ELISA reader at 450 nm wavelength and readings were analyzed using Elisa analysis software.

Estrogen, progesterone and testosterone levels were also measured twice, once after PCOS induction and another after conclusion of treatment using enzyme-linked immunosorbent assay (ELISA) kits from Demeditec company®, Germany. Tests were performed according to manufacturer's manual and specifications.

Ovarian Histomorphology

The excised ovaries were immediately fixed in 10% formaldehyde followed by tissue processing: dehydration through an ascending grade of alcohol, clearance with xylene, infiltration and complete embedding in paraffin wax blocks. Then the blocks were serially sectioned at 3µm thickness using microtome, tissue ribbons were carefully transferred to a warm water bath and allowed to float on the surface to be placed on glass slides, deparaffinized using xylene and rehydrated in downgraded ethanol series. Lastly, they were stained using hematoxylin and eosin stains.

Slides were examined by a veterinary specialist under Life Science Trinocular microscope and pictures of representative sections were taken via a 10 MP digital Euromex camera.