Hydroalcoholic extract of flaxseed improves polycystic ovary syndrome in a rat model

Abstract

Objectives: Herbal medicines are an alternative choice for treatment or controlling of polycystic ovary syndrome (PCOS). Effect of hydroalcoholic extract of flaxseed was evaluated on ovarian hormones and histological changes of uterus and ovary in a PCOS-induced rat model.

Materials and methods: Twenty four rats divided into four groups including negative control, positive control, PCOS and treatment groups. Positive control group received hydroalcoholic extract of flaxseed for 30 days. PCOS was induced by single intramuscular injection of estradiol valerate. Treatment group was treated with flaxseed extract 7 weeks after induction of PCOS for 30 days. Ovaries and uterus were dissected out and their sections were used for histomorphometric study. Levels of estradiol, progesterone, testosterone and dehydroepiandrosterone (DHEA) were measured in the serum.

Results: In the treatment group, flaxseed extract increased level of progesterone (P<0.05), while decreased testosterone (P<0.05) compared with the PCOS group. Concentrations of estrogen and DHEA did not change significantly in comparison with the PCOS group. Histomorphometric study showed that in the treatment group, the number of preantral follicles, antral follicles and corpus luteum increased compared with the PCOS group (P<0.05), but the number of cystic follicles and diameter of antral follicles decreased (P<0.05), and the number of primary follicle did not alter significantly. In the treatment group, the thickness of granulosa layer increased, but the thickness of theca layer and tunica albuginea decreased compared to the PCOS group (P<0.05).

Conclusion: Hormonal profile and histomorphometric features of ovary that were disturbed by PCOS induction were ameliorated by hydroalcoholic extract of flaxseed.

Keywords: Flax; Ovary; Polycystic ovary syndrome Rats; Sex hormones; Uterus.

Figure 1

Schematic diagram of the experimental design including induction model, treatment, vaginal smear checking and sampling time for evaluation of the effect of hydroalcoholic extract of flaxseed on polycystic ovary syndrome (PCOS) in a rat model. EV, estradiol valerate; SO, sesame oil

Figure 2

Vaginal smear of rats for detection of reproductive cycle. (Giemsa staining, index bars, 50 μm)

Figure 3

Effects of flaxseed extract on polycystic ovary syndrome (PCOS) rats and plasma concentrations of estradiol, progesterone, testosterone, and dehydroepiandrosterone (DHEA). Values presented as mean±SEM, the above lines indicate significant difference between groups

Figure 4

Survey views showing negative control (A), positive control (B), estradiol valerate-exposed rat (C), and flaxseed extract-treated rat (D) ovaries in the same magnification. Pr, primary follicle; Pa, preantral follicle; An, antral follicle; Cy, cystic follicle; Cl, corpus luteum (H&E staining; index bars, 200 μm)

Figure 5

A and B, healthy tertiary follicle in the negative and positive control rats. The theca layers and granulosa layers appear normal. C, A follicle in the early process of atresia with apoptotic granulosa cells, most of which are in the inner parts of the granulosa layer in a polycystic ovary syndrome (PCOS) rat. Thin and elongated epithelioid cells form the inner surface of the wall. The cyst fluid contains macrophages. D, Ovary from a flaxseed-treated PCOS rat with normal tertiary follicles. Gl, granulosa layer; Tl, theca layer (H&E staining; index bars, 50 μm)

Figure 6

Uterine tissue sections of negative control (A), positive control (B), estradiol valerate-exposed rats (C), and flaxseed extract-treated (D) rats. El, endometrial layer; Ml, myometrial layer (H&E staining; index bars, 50 μm)