Lepidium sativum Effects on Regulation of Reproduction, Hematological, and Metabolic Indices in Sprague-Dawley Rats

Lepidium sativum (LS) or Garden Cress (GC) is an erect, glabrous, annual herbaceous fast-growing edible plant, belonging to Brassicaceae family grows up to 15-45cm in height. Its easy cultivation and its tolerance to different environmental conditions gave it the ability to spread all around the world. Lepidium sativum (LS) seeds are consumed as part of regular diets and used in traditional medicine in many parts of the world to treat different kinds of ailments including hyperglycemia, fracture healing, diarrhea, hypertension, microbial infections, hepatoprotective activity, bronchial asthma, cancer and other disorders. To date, there has been no systematic study done to evaluate the potential effects of LS on reproduction, on GnRH pulsality or on the pulsatile or surge secretions of LH and FSH at brain level. Evidently, the reports from the studies have suggested conflicting results on the effect of LS on reproduction in female and male. LS possess anovulatory and abortifacient properties in females while aphrodisiac effect in males. Furthermore, like many herbs used in folkloric medicine, there is no information as to what constitutes pharmacologic inclusion level. The highest level of inclusion of LS seeds at 50% has shown lethal effects while 10% LS seed inclusion has shown ambiguous toxic and non-toxic effects. Therefore, the objectives of the study were to determine the effect of methanolic LS seed extract on the development and magnitude of pulsatile releases of GnRH, LH and FSH and secondly, to determine the acute and chronic effects of 15% LS seed supplementation on hematological and metabolic indices in the Sprague-Dawley rat. Twenty mature female rats were ovariectomized and implanted with estradiol -17β (OVEX+ E2) three weeks before euthanization using standard procedures. After three weeks of ovariectomy, rats were randomly assigned to either of 4 groups: Control (n = 5; 0mg/mL aCSF), Low group (n = 5; 10mg/mL LSE), Mid group (n = 5; 20mg/mL LSE), or High group (n = 5; 40mg/mL LSE). Rats were euthanized using an overdose of Tribromoethanol and both the hypothalamus and pituitary gland of each rat were harvested and perifused separately in artificial cerebrospinal fluid for six hours at a constant temperature of 37°C, and with 95% O2 and 5% CO2 aeration. Perifusates were collected at 7.5 minutes for a total of 5 hours consisting of a 120minute baseline period followed by application of either aCSF or aCSF containing different concentrations of LSE and perifusate collection for 2 hours and finally administration of KCl to the hypothalamic explant or GnRH to the pituitary explant and a final perifusate collection for 60 minutes. LH and FSH concentrations were determined utilizing radioimmunoassay. LSE administration potently stimulated GnRH and gonadotropins secretions. There was no effect of LSE administration on the pulse frequency of GnRH, LH and FSH but LSE significantly increased GnRH pulse amplitude only. The GnRH, LH and FSH hormone secretions were pulsatile both in control and treated groups throughout the sampling period. Forty-eight male,7 to10 week old Sprague-Dawley rats were utilized for experiment 2 to determine the effect of LSSP on hematological and metabolic indices. Rats were acclimated to housing and feeding conditions for two weeks and then randomly sorted into either of two groups namely Control (0% LS seed inclusion; n = 24) or Treated (15% LS seed inclusion; n = 24) and fed throughout the 8-week duration of this study. Body weights of animals were recorded every other day. Every 2 weeks, 6 rats from each group were sacrificed and trunk blood 3 samples were collected for hematological and metabolic indices determination. Ingestion of LSSP at 15% had no effect on red blood cells (RBC) count, hematocrit (HCT), hemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). No significant effect of LSSP ingestion was observed on plasma glucose concentration or BUN was observed. However, plasma creatinine concentration decreased significantly (P < 0.0001) overtime. LSSP ingestion for 8 but not for 6 weeks significantly (p = 0.045) reduced total protein and albumin levels but both shortand long-term LSSP ingestion reduced plasma globulin levels. There was no effect of LS supplementation on alanine transaminase (ALT) and aspartate transaminase (AST), although there was an insignificant increase in alkaline phosphatase (ALP) level in LSE-fed rats in the short-term. Overall, irrespective of treatment, ALP levels were significantly higher (P = 0.005) after 8 weeks of either normal chow or LSSP feeding. Overall, results of our studies indicate the stimulatory effect of LSE administration on GnRH and gonadotropins secretion. There was no effect of LSE administration on the pulse frequency of GnRH, LH, and FSH but LSE significantly increased GnRH pulse amplitude only. Ingestion of LS seeds at a 15% level in the diet had no deleterious effects on hematological and metabolic indices in the rat.