Portulaca oleracea shows no ameliorative potential on ovariectomy-induced hormonal and estrous cycle dysregulation in normal cyclic rats: An experimental study

Abstract Background Portulaca oleracea (PO) is a widely known plant utilized for its medicinal attributes in the treatment of different illnesses. Objective To investigate the effect of methanolic extract of PO (MEPO) on ovariectomy-induced reproductive toxicity in normal cyclic rats. Materials and Methods Twenty 10-wk-old normal cyclic rats weighing 110-200 g were randomly divided into four groups (n = 5/group). Group A served as the control and received distilled water only. Group B was ovariectomized without treatment, while groups C and D were ovariectomized but treated with 400 and 800 mg/kg of MEPO, respectively, for 14 days. At the end of the experiment, body weight, serum hormonal levels, and estrous cycles were monitored across the groups. Results Groups B, C, and D showed estrous cycle dysregulation and specific phase arrest when compared with the control. While a significant decrease in estradiol (p ≤ 0.001) and testosterone levels (p ≤ 0.001) were observed in groups B, C, and D, only groups C and D showed a significant increase in progesterone level when compared with the control (p ≤ 0.001, p = 0.01, respectively). Conclusion The administration of 400 and 800 mg/kg MEPO is ineffective in ameliorating estrous cycle disruption and hormonal changes seen in ovariectomized normal cyclic adult Wistar rats.


Introduction
There is a growing tendency in the search for natural herbs with scientifically-proven anti-inflammatory, anti-cancer, anti-microbial (4), immunological (5), and hepatoprotective properties (6). Several studies on reproduction have reported the effect of the administration of purslane including decrease in sperm motility and testosterone (TT) levels (7), sperm morphology distortions (8), and alteration of the estrous cycle (9).
Evaluation of the menstrual cycle (synonymous with the estrous cycle in rats) remains an indispensable measure of the normal reproductive state in humans. However, the short cycle length of rats makes it an ideal animal for studying changes during the reproductive cycle (10). Reproductive cycle disorders are associated with some infertility-related diseases in which ovariectomy (the surgical removal of the ovaries) is often carried out; for example, ovarian cyst, endometriosis, ectopic pregnancy, and pelvic inflammatory disease. It has been reported that about 10% of the world's female infertility cases require ovariectomy (11). The reproductive cycle is influenced by ovariectomy because the ovaries are chiefly responsible for the production of the female sex hormones -estrogen and progesterone (PG).

Study setting
This experimental study was undertaken in the research laboratory of Anatomy Department of Nnamdi Azikiwe University between January-April, 2019.

Animal sacrifice and blood sample collection
After the administration on the 14 th day, all the animals from the groups were fasted overnight and euthanized the next day by cervical dislocation. Blood samples were collected by orbital puncture into appropriately labelled plain tubes. The blood was centrifuged and blood serum was extracted.

Hormonal analysis
The

Ethical considerations
The experimental procedures complied with

Estrous cycle examination
The estrous cycle across the study groups  Table II.

Serum LH, FSH, E2, TT, and PG
There was no significant difference in the FSH and LH levels in the OVX, OVX400, or OVX800 groups when compared with the control group (p = 0.73 and p = 0.15, respectively). E2 and TT levels showed a significant decrease in the OVX, OVX400, and OVX800 groups when compared to the control group (p ≤ 0.001). Only OVX400 and OVX800 groups showed a significant increase in PG levels when compared with the control group (p ≤ 0.001 and 0.01, respectively) (Table III). 110.23 ± 9.92 198.67 ± 6.33 * 44.5 Data presented as Mean ± SEM. Student dependent t test. Data were considered significant at p < 0.05. * P < 0.05, which indicates a significant difference between the pre-and post-administration body weights. The % difference in body weight change for each group was derived from the mean difference between pre-and post-administration body weights. OVX: Ovariectomized only, OVX400: Ovariectomized + 400 mg/kg MEPO, OVX 800: Ovariectomized + 800 mg/kg MEPO  There were no differences in the impact of ovariectomy and the administration of MEPO following ovariectomy on the animal body weight (Table I). Several

Conclusion
This study has reestablished that ovariectomy causes a significant decrease in TT and E2 and also disrupts the estrous cycle in rats.
More importantly, it has given clear evidence for the lack of potential of MEPO to repair ovariectomy-induced endocrine and estrous cycle damages. According to the findings, 400 and 800 mg/kg MEPO does not play any role in maintaining the normal estrous cycle and reproductive hormonal output in the absence of the ovaries.