Therapeutic Effects of Cynodon dactylon (C. dactylon) against Polycystic Ovary Syndrome Induced by Letrozole in Adult Rats: Ovarian and Uterine Aspects

Abstract

Background: Cynodon dactylon traditionally employed or treating hormonal problems in women. Therefore, this study aimed to assess the effect of C. dactylon hydroalcoholic extract of on letrozole-induced polycystic ovary syndrome (PCOS) in adult rats.

Materials and methods: In this experimental study, hydroalcoholic extract was prepared from the whole plant except the root. Then, 16 female Sprague-Dawley rats were divided into four groups. In the control group, the PCOS model was not induced and no treatment was performed. The PCOS-induced groups received 1 mg/kg of body-weight letrozole daily by gavage for 21 days. In the PCOS-induced groups two groups were orally treated with 250 mg/kg body weight daily metformin or 500 mg/kg body weight daily C. dactylon extract, 28 days after PCOS induction. Hormonal, histopathologic, and histomorphometric analyses were performed. Molecular docking also done to evaluate effect of C. dactylon extract on receptors involved in the pathophysiology of PCOS.

Results: C. dactylon had a remarkable positive effect on estrous cycles and also led to a significant reduction in the weight of PCOS rats. Moreover, C. dactylon extract mitigates PCOS-induced hormonal imbalances including a significant decrease in testosterone and estrogen levels, as well as increased progesterone levels. Ovarian and uterine structures were improved including reducing theca layer thickness, enhancing antral follicular areas, and a significant decrease in the luminal area of the perimetrial layer, endometrial glands, and the total uterine area when compared to the PCOS group. Besides, molecular docking analysis showed that Ar-tumerone, Tumerone, Tricyclo[6.3.0.0(1,5)] undec-2-en-4-one, 2,3,5,9- tetramethyl, Curlone, and 3-Tert-butyl-4-hydroxyanisole showed the most binding affinity to the receptors that play crucial role in the pathophysiology of PCOS.

Conclusion: C. dactylon extract could display positive effects on both the ovary and uterus of letrozole-induced PCOS rats. Therefore, C. dactylon had therapeutic effects on the ovary and uterus of PCOS-induced rat models.

Keywords: Cynodon dactylon; Ovarian follicles; Polycystic Ovary Syndrome; Sex Hormones; Uterus.

Fig 1

Therapeutic effects of Cynodon dactylon (C. dactylon) on stages of estrus cycle and weights after induction of PCOS in letrozole-induced adult rats. A. Diagrams illustrating various stages of the estrus cycle in the control group, PCOS group, metformin-treated PCOS rats, and C. dactylon extract-treated PCOS rats. B. Proportion of stages of the estrus cycle during three study periods: before induction (evaluation), during induction (induction), and after induction (treatment) in the four study groups. Lines above the columns indicate significant differences between the columns (P<0.05). C. Mean and standard error of body weight in rats during different study periods in the four groups. Stars of the same color as the lines denote statistical differences on each day. PCOS; Polycystic ovary syndrome, *, P<0.001, **; P<0.01, and ***; P<0.05.

Fig 2

Serum hormone concentrations (means and standard errors) to evaluate the therapeutic effects of Cynodon dactylon against polycystic ovary syndrome induced by letrozole in adult rats. A. LH, B. FSH, C. LH/FSH, D. Testestrone, E. Estrogen, and F. Progestrone. PCOS; Polycystic ovary syndrome, FSH; Follicle-stimulating hormone, LH; Luteinizing hormone, *, **, and ***; Denote significance at the 1, 2, and 5% probability levels, respectively.

Fig 3

Ovarian follicle counts (means and standard errors) to evaluate the therapeutic effects of Cynodon dactylon against polycystic ovary syndrome induced by letrozole in adult rats. A. Number of primary follicle/slice, B. Number of secondary follicle/slice, C. Number of tertiary follicle/slice, D. Number of cystic follicle/slice, E. Number of atretic follicle/slice, F. Number of corpus luteum/slice. No statistically significant difference in the means was found. *, **, and *** indicate significance at the 1, 2, and 5% probability levels, respectively. Histological changes in ovaries of rats with letrozole-induced polycystic ovary syndrome (PCOS). Identification of corpus luteum (black stars) and normal tertiary follicles (arrows). PCOS-induced cystic follicles marked with black stars [hematoxylin and eosin staining (H&E)]. G. Control group, H. PCOS group, I. Metformin-treated group, and J. C. dactylon treatment group.

Fig 4

Comparison of the area of different layers of tertiary follicles across groups: absolute and relative measurements. A-D. Means and standard errors of the area of different layers of tertiary follicles were observed in different groups. There is no statistically significant difference in the mean. E-G. Means and standard errors of the area of different layers of tertiary follicles relative to total follicles were observed in different groups. No statistically significant difference in the mean was found. *, **; Denote significance at the 1, and 5% probability levels, respectively, and PCOS; Polycystic ovary syndrome.

Fig 5

Ovary and uterine histomorphometry. A-F. Means and standard errors of the area of different areas of uterine tissue were observed in different groups. There is no statistically significant difference in the mean. G-J. Mean and standard errors of different areas of uterine tissue to the whole uterus were observed in different groups. There is no statistically significant difference in the mean. *, **, and ***; Significant at 1, 2, and 5% probability levels, respectively. Histological changes in uterus of rats with letrozole-induced polycystic ovary syndrome (PCOS) are stained with hematoxylin and eosin stain- ing (H&E): K. Control group, L. PCOS group, M. Metformin-treated group, and N. C. dactylon treatment group.