[Effects of electro-acupuncture on signal transduction pathway of hypothalamic neuroendocrine system in ovariectomized rats].

OBJECTIVE: To compare the varieties and contents of the main nerval information molecules in perfusate from hypothalamic medial preoptic area (MPOA) of the rats in different sexual cycles and the ovariectomized rats treated by electro-acupuncture, so as to observe the similarities and differences of hypothalamic neuroendocrine signal transduction pathway under the physiological and pathological status, and to explore the mechanisms of neuroendocrine signal transduction of electro-acupuncture therapeutic effect in perimenopausal syndrome. METHODS: The stereo localization technique and push-and-pull perfusion of the rat brain nucleus were adopted for collecting the hypothalamic MPOA perfusate of the female rats with normal sexual cycle, and also for collecting the MPOA perfusate of ovariectomized rats after electro-acupuncture treatment as acupuncture perfusate (AP). After being respectively microinjected into MPOA of the ovariectomized rats, the influence of the different perfusates on vagina cytology and serum estradiol (E2) level was observed. The contents of gonadotropin-releasing hormone (GnRH), dopamine (DA), gamma-aminobutyric acid (GABA), glutamate (Glu), aspartate (Asp) and beta-endorphin (beta-EP) in the perfusate of each group were detected by radioimmunoassay or high performance liquid chromatography, and then the varieties and contents of these substances in the perfusate of each group were compared and analyzed. RESULTS: The contents of neural active substances including DA, GABA, Glu, and beta-EP in the perfusate from the rats' MPOA during different stages of sexual cycle showed some regular changes. After the perfusate was microinjected respectively into the MPOA of the ovariectomized rats, the changes of animal vaginal exfoliated cells and serum E2 level showed the similar four-stage cycle characteristics as normal rats; the changes of vaginal exfoliated cells and serum E2 level of the ovariectomized rats without electro-acupuncture treatment showed the acupuncture-like effects following the microinjection of AP in the MPOA. CONCLUSION: The information molecules in the perfusate from MPOA of rats in normal sexual cycle or electro-acupuncture-treated rats include classical neurotransmitters, amino acid neurotransmitters, and neuropeptides. Acupuncture may modulate the release and synthesis of these information molecules to normalize the subnormal function of MPOA in perimenopausal period. Thus, AP may be a neuroendocrine signal carrier of acupuncture effects for acupuncture signal transduction from one individual to another. This may provide a new thinking and method for studying acupuncture signal transduction of the acupuncture therapeutic effects on perimenopausal syndrome.

G-1 exhibit antidepressant effect, increase of hippocampal ERs expression and improve hippocampal redox status in aged female rats.

Postmenopausal depression has been shown to be related to the reduction of ovarian hormones produced as a woman transitions from a menopausal to a post-menopausal stage. What remains to be known is which type of estrogen receptor plays a key role in estrogen neuroprotection, a process that may be mediated by potentiating brain mitochondrial function and inhibiting mitochondria-associated apoptosis. In order to better imitate the condition of postmenopause, we conducted our research on aged female rats. Plasma estrogen levels declined significantly in ovariectomized rats and 16-month-old female rats, while anxiety and depression-like behavior increase. Moreover, ERα, ERß, GPER, Bcl2 and UCP2 expression decreased significantly in hippocampus in female rats following ovariectomy. In our study, the anxiety and depression-like behavior in aged female rats were significantly relieved after the treatment of G-1, the GPER agonist. Furthermore, G-1 could reverse the reduction of ERα, ERß, GPER, Bcl2 and UCP2 expression within the hippocampus. Mitochondrial JC-1 staining indicated that mitochondrial membrane potential increased after G-1 treatment. In addition, total antioxidant capacity (TAC) and superoxide dismutase activity (SOD) were found to be elevated in aged female rats following G-1 treatment. Taken together, estrogen receptors, especially GPER, may activate anti-apoptotic signaling and accelerate mitochondrial function. Therefore, GPER could be the potential therapeutic target for estrogen deficiency-related affective disorders.

Electroacupuncture stimulates the expression of prolactin-releasing peptide (PrRP) in the medulla oblongata of ovariectomized rats.

Electroacupuncture (EA) in reproductive medicine has become established in Western medicine as a therapy over the last decade. EA performs a variety of neuromodulatory functions in the central nervous system (CNS). Prolactin-releasing peptide (PrRP) is a neuropeptide identified as an endogenous ligand for the orphan G protein-coupled receptor hGR3. PrRP can affect the function of hypothalamus-pituitary-ovary axis (HPOA) and hypothalamus-pituitary-adrenal axis (HPAA). The present study was undertaken to characterize the effect of EA on the expression of PrRP in the medulla oblongata in ovariectomized (OVX) rats by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). In addition, estrogen (E2) levels were detected by radioimmunoassay (RIA). The results suggest that EA significantly increase the blood level of E2 and the expression of PrRP in the medulla oblongata of OVX rats. The number of PrRP immunoreactive (ir) neurons was higher in the group ovariectomized with EA than that in the OVX group. The numbers of PrRP-ir neurons in intact (INT) and intact with EA (INT+EA) were not significantly different between the two groups. The expression of PrRP mRNA was increased in the OVX+EA group than that in the OVX group. These results suggest that the mechanism that EA improved reproductive disorders induced by ovariectomy in rats is related to the modulation of the blood E2 level and the expression of PrRP in the medulla oblongata.

[Effects of electroacupuncture on the expression of corticotropin-releasing factor (CRF) family and CRF receptor 1 in traumatic injury rats].

OBJECTIVE: To observe the effects of electroacupunture (EA) on the abnormal hypothalamus-pituitary-adrenal (HPA) axis and the expression of hypothalamic corticotropin-releasing factor (CRF) peptides family and CRF receptor (R)1 mRNA in traumatized rats, so as to study its underlying mechanism in improving traumatic injury. METHODS: Forty male Sprague-Dawley rats were randomly divided into normal control group (n=10), normal+ EA group (n=10), surgical trauma (model) group (n=10), and model+ EA group (n=10). Traumatic injury model was established by performing an exploratory laparotomy in the rats under anesthesia. EA (2 Hz/15 Hz, 1-2 mA) was administered for 30 min via two stainless steel needles inserted in "Zusanli" (ST 36) and "Sanyinjiao" (SP 6). Serum adrenocorticotropic hormone (ACTH) , corticosterone (Cort), luteinizing hormone (LH) and testosterone (T) contents were detected by double-antibody radioimmnoassay. Hypothalamic CRF and ORF R1 mRNA expression was assayed by reversed transcription polymerase chain reaction (RT-PCR) technique. RESULTS: The serum ACTH concentration decreased significantly in model group (P < 0.05) compared with those in normal control and normal+ EA groups, and was significantly higher in model+ EA group than that in model group (P < 0.05). No significant difference was found between normal control and normal+ EA groups in serum ACTH levels (P > 0.05). The serum Cort level increased significantly in model group (P < 0.05) compared with those in normal control and normal + EA groups, and was obviously lower in model+EA group than that in model group (P < 0.05). While serum LH and T contents had no apparent changes in the four groups (P > 0.05). The expression of hypothalamic CRF mRNA decreased significantly in model group (P < 0.05) compared with that in normal control group, but increased significantly in model + EA group (P < 0.05) compared with that in model group. However, no significant difference was found between normal control and normal + EA groups in the CRF mRNA expression level. The expression of hypothalamic Ucn 1 mRNA increased significantly in model group than that in normal control group (P < 0.05), and decreased considerably in model+ EA group than that in model group (P < 0.05). There were no significant changes in the expression of hyp, thalamic Ucn 2 mRNA, Ucn 3 mRNA and CRF R1 mRNA in the four groups (P > 0.05). CONCLUSION: EA of "Zusanli" (ST 36) and "Sanyinjiao"(SP 6) can improve surgical trauma-induced HPA disorders, which is probably related to its effects in upregulating CRF mRNA expression and downregulating Ucn 1 mRNA expression in the hypothalamus.

[Effects of different segments of acupuncture serum on eosinophil counts in the rat with eosinophilia].

OBJECTIVE: To further analyze and identify effective components of anti-asthma in acupuncture serum. METHODS: Changes of eosinophils in the peripheral blood of rats with eosinophilia were observed for 10 days after intravenous injection of the different segments of serum (serum: normal saline = 1:20, 2.5 mL/kg, from the first day of the model establishment, for 3 consecutive days). RESULTS: After intravenous injection of different segments of serum, the eosinophil counts in the peripheral blood decreased significantly from the 3rd day as compared with those of the model group (P<0.05). CONCLUSION: The effective components of acupuncture serum from asthmatic rats treated by acupuncture for eosinophils are not a single component, and acupuncture stimulation may produce many kinds of components of anti-asthma.

Involvement of nociceptin/orphanin FQ in release of hypothalamic GnRH mediated by ORL1 receptor in ovariectomized rats.

AIM: To investigate effect of the nociceptin/orphanin FQ (OFQ) on hypothalamus gonadotropin-releasing hormone (GnRH) release in ovariectomized (OVX) rats. METHODS: GnRH radioimmunoassay (RIA) was used to study the effect of OFQ on GnRH release in hypothalamus slices in vitro. Push-pull perfusion and intracerebroventicular (icv) injection were used to examine the effect of OFQ on GnRH release in the hypothalamus medial preoptic area (POA) in vivo. Ovariectomies were performed on female Sprague-Dawley rats, and their plasma luteinizing hormone (LH) levels were measured after icv injection of OFQ with or without [Nphe1]NC(1-13)NH2, a competitive antagonist of opioid receptor-like1 receptor (ORL1 receptor). Reverse transcription-polymerase chain reaction (RT-PCR) was used to investigate the expression of the ORL1 receptor in rat pituitary. RESULTS: GnRH release from hypothalamus slices was inhibited 90 min after the administration of 2 mmol/L and 20 mmol/L OFQ (P<0.05). Accordingly, GnRH release from hypothalamus POA was also significantly reduced by the injection of 0.2 mmol/L and 2 mmol/L OFQ. Plasma LH levels were also decreased significantly 2 h after icv injection of 20 nmol OFQ in OVX rats (P<0.05) and this effect could be abolished by pretreatment with 20 nmol [Nphe1]NC(1-13)NH2, that is, NC13. More interestingly, plasma LH levels in OVX rats increased markedly 2 h after icv injection of 100 nmol and 200 nmol NC13. RT-PCR analysis further revealed that the ORL1 receptor was not expressed in the pituitary of OVX rats. CONCLUSION: Central administration of nociceptin/orphanin FQ might inhibit the release of hypothalamic GnRH and decrease the plasma LH levels through ORL1 receptors in OVX rats.