RESUMO
Objective To explore the effect of melatonin ( MLT) on the initiation of puberty in female mice and on the expression level of phosphatidylinositol-3-kinases ( PI3K)/protein kinase B ( Akt)/mammalian target of rapamycin (mTOR) signaling pathway in the frypothalamus. Methods Seventy-eight 20-day-old female KM mice were randomly divided into melatonin (MLT) group and normal saline (NS) group, with 39 mice in each group. Starting at 22 days of age, the MLT group was given a subcutaneous injection of 1 mg/kg melatonin and the NS group was given an equal volume of saline. Thirty-two days of age were selected as the sampling point before puberty initiation and 13 mice were executed in each of the two groups, while 37 and 42 days of age were selected as the sampling point after puberty initiation and 13 mice were executed in each of the two groups. Observation of vaginal opening time in mice, weighing of ovaries and uterus to calculate organ indices. HE staining to observe the number of ovarian corpora lutea. The levels of serum luteinizing hormone (LH)were determined by ELISA. The mRNA and protein expression levels of PI3K/Akt/mTOR pathway in frypothalamus were detected by Real-time PCR and Western blotting. Results Compared with the normal saline group, mice in the melatonin group had significantly delayed vaginal opening time ( P < 0. 05 ) , decreased significantly ovarian and uterine volume and index (P<0. 05) , decreased significantly serum LH levels (P<0. 05) , and decreased significantly mRNA and protein expression levels of the frypothalamic PI3K/Akt/mTOR pathway (P<0. 05). Conclusion Melatonin delays puberty initiation in mice by a mechanism that ma)' be related to inhibition of the hypothalamic PI3K/Akt/mTOR signalling pathway.
RESUMO
Objective To explore the roles and effects of gonadotropin inhibitory hormone gonadotropin-inhibitory hormone (GnIH)/RF amide-related peptide-3 (RFRP-3) on the uterus through the hypothalamic-pituitary reproductive axis. Methods Ovariectomized estrogen primed (OEP) rats model was divided into GnlH injection group and normal saline injection group with 15 rats in each group, 2 g/L GnlH (16 μl/kg) and normal saline (16 (μl/kg) were injected into the lateral ventricle of rats in the 2 groups respectively. 6 hours after injection, the uterine fluid of rats was obtained. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to separate the differential proteins in uterine fluid and UniProt was used to identify. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, and the proteinprotein interaction (PPI) network of the differentially expressed proteins was constructed using Cytoscape 3.7. 1 software. Hub proteins were detected from PPI network. Results The result showed that the differentially expressed proteins separating by LC-MS/MS were 419 identified by UniProt. Among them, 279 were up-regulated and 138 were down-regulated. GO analysis showed that the differentially expressed proteins were mainly involved in response to organic substance, response to oxygen-containing compound, response to endogenous stimulus, response to stress. The top five enriched pathways obtained in the KEGG pathway analysis (P<0.05) were carbon metabolism, gap junction, long-term depression, regulation of actin cytoskeleton, biosynthesis of amino acids. Five hub proteins involved albumin (Alb), alpha-enolase 1 (Enol), peroxiredoxin-6 (Prdx6), tissue inhibitor of matrix metalloproteinases-1 (Timp 1), Ras-related C3 botulinum toxin substrate 1 (Racl) were obtained by analyzing PPI network. Conclusion The result of this study indicate that GnlH may regulate the secretion of uterine cavity fluid protein through hypothalamic-pituitary reproductive axis. And regulate the physiological and pathological process of uterus by up-regulating Alb, Enol, Prdx6 and down-regulating Timpl and Racl.