ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
To investigate the effects of leptin on glucose metabolism and related inflammatory factors in diabetic rats. Methods: Ten healthy male Wistar rats were randomly selected as the control group. Fifty rats were fed with high sugar and high fat diet and injected with streptozotocin (STZ, 25 mg/kg) intraperitoneally. They were randomly divided into model group, leptin low, middle and high dose group. The rats in the low, middle and high dose group were fed with leptin at the doses of 20, 50 and 100 μg/kg for 5 d respectively. Blood glucose (FBG) was measured by GOD-PAP method, insulin content (INS) was tested by radioimmunoassay, the serum levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL-C) and high density lipoprotein (HDL-C) were determined by automatic biochemical analyzer, the contents of malondialdehyde (MDA), interleukin-6 (IL-6) and tumor necrosis factor (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). Western blot was used to detect the expression of leptin in adipose tissue of diabetic rats. Compared with the control group, the blood glucose levels of other groups were increased significantly (P＜0.01). Compared with the model group, the blood glucose levels of middle and high dose leptin rats decreased significantly (P＜0.05, P＜0.01). The insulin level of high dose leptin group decreased significantly (P＜0.01). There was no significant difference in FBG and INS among the three groups (P＞0.05). Compared with the model group, TC levels of middle and high dose leptin group were decreased significantly (P＜0.05, P＜0.01). TG and LDL-C levels of high dose leptin group were decreased significantly (P＜0.05), HDL-C level of high dose group was increased significantly (P＜0.01). Compared with different dose groups, the high dose of leptin (100 μg/kg) could decrease the levels of TC, TG and LDL-C, and increase the level of HDL-C, which was better than those of the middle and low dose of leptin (P＜0.05) Compared with the model group (52.27±10.93), the levels of leptin in low, middle and high dose group were (47.35±12.09), (44.68±10.23) and (40.13±9.87) respectively, which could be decreased by leptin in a dose-dependent manner. The abnormal secretion of leptin is one of the factors inducing diabetes mellitus. Under the intervention of a certain concentration of exogenous leptin (100 μg/kg), it can significantly reduce the level of MDA, TNF-α, and improve the level of IL-6. The mechanism may be closely related to the reduction of inflammatory response, oxidative stress and correction of dyslipidemia. Leptin also reduces the risk of disease progression in diabetes treatment.