Effects Of Dietary Major Royal Jelly Proteins(MRJPs)on Reproductive Performance Of Female Mice And Related Mechanisms

In present,with the rapid development of society and the increasing pressure of life,the reproductive health issues of female population are receiving more and more attention.Royal jelly?RJ?is recognized as a natural health food at home and abroad.It possesses various physiological effects such as antifatigue,anti-inflammatory,antioxidation and immune regulation.Over the years,although there have been many reports on the estrogen-like activity and reproductive function of RJ,the effects of its key active ingredient,the major royal jelly proteins?MRJPs?on the reproductive function and endocrine regulation remain unclear.In this study,lyophilized MRJPs power was used as the research object,and female ICR mice were used as animal models to study the reproductive endocrine regulation of MRJPs on perimenopause and adolescence,when is regared as the critical period in females.The research contents and results are as follows:1.Effects of MRJPs on reproductive endocrine in peri-menopausal female mice and its mechanismNatural aging female ICR mice with age with 11-13 months were selected to simulate the physiological state of female menopause,and a perimenopausal model was established.Fifty female mice were randomly divided into 5 groups including low,middle and high dose of MRJPs?125,250,500 mg/kg;hereinafter referred to as M125,M250 and M500,respectively?,casein control group?125 mg/kg,Casein?and old model group.Meanwhile,ten female mice with age of 5 months were set as the young control group.All mice were conducted intragastric administrations once a day for 7 weeks.The body weight of the mice was measured weekly.The index numbers of uterus and ovary coefficients?IUOC?were calculated,and serum levels of estradiol?E₂?,progesterone?P?,follicle stimulating hormone?FSH?,and luteinizing hormone?LH?were detected by radioimmunoassay.The real-time PCR was used to detect the expression of estrogen receptor??ER??,estrogen receptor??ER??and progesterone receptor?PR?.The histomorphological observation of the uterus and ovary was also carried out.The obtained results showed that the ovary index in M125,M250 and M500 were increased by 4.19%,7.53%and 9.35%,respectively compared to the CK.The uterine index in M125,M250 and M500 were increased by 4.21%,4.96%and6.85%,respectively compared to the CK.The levels of serum E₂ in M250 and M500were significantly elevated by 15.84%,28.43%and 34.7%,and the levels of P were also significantly increased,while the levels of FSH and LH in all MRJPs group were decreased compared to the elderly controls.The average thickness of endometrium in M125,M250 and M500 were increased by 3.2%,3.54%and 3.58%respectively compared to the elderly model group.The expressions of ovarian ER?,ER?and PR in MRJPs groups were up-regulated significantly.Ovarian morphology and follicular development in MRJPs groups were significantly improved.The above results indicate that MRJPs have an estrogen-like effect and have reproductive protection effects on peri-menopausal mice.These results have certain academic value for finding safe and effective hormone substitutes,and will provide important scientific evidences of MRJPs and RJ using in prevention and improvement of menopausal syndrome in future.2.Effects of MRJPs on puberty onset and ovarian follicle development in immature female mice.Neonatal female mice were randomly divided into four groups:three experimental groups were fed supplemental MRJPs with different doses:125,250and 500 mg/kg/body weight?M125,M250 and M500?,and the control.MRJPs was administrated daily for 45 consecutive days.Vaginal opening and estrous cycle of all mice were monitored.The body weight was recorded every 2 days.Ovarian index and uterus index were calculated.Finally,the serum was killed and the content of estradiol and progesterone was determined by radioimmunoassay.The development of follicles was evaluated by histological examination.The antioxidant index of ovarian tissue was determined.The results indicated that the time of puberty onset in M125,M250 and M500 were accelerated by 11%,15.71%and 9.93%.The ovarian index of M125 and M250 were increased by 26.79%and 32.14%,respectively,and the uterus index in M250 was increased by 13.12%compared to the CK.The serum estradiol of M125,M250 and M500 were increased by 47.13%,64.85%and 31.11%compared to the CK,respectively.Progesterone level in M250 was increased by114.02%compared to the CK.The number of secondary follicles in M125,M250were increased by 50.7%and 78.8%,and Graafian follicles in M125,M250 were increased by 600.0%and 776.0%,respectively,compared to the CK.The expressions of ovarian ER?in MRJPs groups were up-regulated significantly.Antioxidant parameters of the ovary issue showed that malondialdehyde?MDA?level in M125and M250 was decreased by 24.60%and 26.74%,respectively,compared to CK.Compared to the CK,the superoxide dismutase?SOD?activities in M125 and M250were increased by 11.33%and 18.14%,and the glutathione peroxidase?GSH-PX?activity were increased by 19.19%and 19.60%,respectively.In conclusion,early prepubertal supplement of MRJPs accelerated the onset of puberty and promoted follicular development in female mice.