| Object Hypothalamus-pituitary-adrenal (HPA) axis as the key mederator in energy metalbolism plays an important role in type 2 diabetes. A number of studies find that cannabinoids receptors almost expressed in all regions of the hypothalamus. Simultaneously, endogenous cannabinoid system (eCBs) is concerned with neuronal function according to a spate of reports. But there are few data for us to affirm the relationship between eCBs and HPA axis. It is imperative to investigate whether the dysfunction of HPA axis is associated with the changes of eCBs.Methods To probe the theory above, five overt type 2 diabetes monkeys, five prediabetes monkeys and five healthy monkeys were used in this study. After sacrificed, the hypothalamus, pituitary and adrenal of all monkeys were dissected instantly, and cryopreservation and paraformaldehyde fixation were used for the next test. Hematoxylin-eosin stain and immunohistochemistry (IHC) were aimed at detecting the variation of pathology and protein distribution. Synchronously, the protein levels and gene expression levels were checked by western blotting and real time polymerase clain reaction respectively. At last, the level of cortisol of monkey’s adrenal gland was tested by enzyme linked immunosorbent assay. In this study, the function of HPA axis was estimated by the relative expressions of corticotropin releasing hormone (CRH) and glucocorticoids receptor (GR) in hypothalamus, corticotropin releasing hormone receptor 1 (CRHR1), adrenocorticotropic hormone (ACTH) and GR in pituitary gland, adrenocorticotropic hormone receptor (ACTHR), 11β-hydroxylase (11β-HSD) and cortisol in adrenal gland. On the other hand, the eCBs function was evaluated by cannabinoids receptor 1 (CB1R), fatty acid amide hydrolase (FAAH), and monoglycerol lipase (MAGL) in the hypothalamus.Results It is finding that neuronatrophy was existed extensively in the hypothalamic paraventricular nucleus (PH) in prediabetes and overt diabetes monkeys compared with the healthy monkeys. Cellular swelling was distributed in adrenal cortex zona fasciculate of pre- and overt diabetes. CRH, CB1R, FAAH and MAGL distributed in the PH of monkeys by immunohistochemistry. At the same time, the positive staining productions of CRHR1, ACTH, ACTHR and GR were found in the neurohypophysis, adenohypohpysis, fascicular zone of adrenal gland, adenohypohpysis, and PH separately. The integral optical density values of IHC positive production were changed as following:from the health group to the prediabetes and overt diabetes group, a gradual downward trend was existed in the change of CRH, CRHRl decreased firstly but increased later, ACTH increased firstly but decreased later, ACTHR, FAAH and MAGL continuous elevated, GR of PH and adrenal gland continuous decreased, CB1R continuous decreased.The relative expression of proteins by western blotting as below:CRH and GR decreased continually, ACTH and ACTHR increased continually, CRHRl decreased firstly but increased later, CB1R decreased, FAAH and MAGL increased continually. At the same time, Cortisol leve continuous increased from health to overt diabetes by enzyme linked immunosorbent assay.Compared with the healthy monkeys, the prediabetes and overt diabetes monkeys had less CRH mRNA expression. Meanwhile, CRHRl was decreased firstly and increased on the end, but an increasing trend existed in the level of ACTH and ACTHR mRNA.11β- HSD gene was expressed increasingly from health to diabetes. The GR gene expressed less continuous from the health to the overt diabetes. The relative expression of CB1R gene decreased along with the course of diabetes. On the contrary, FAAH and MAGL increased.Conclusions From the health to the pre-T2DM and the overt T2DM, HPA axis has a hyperfunctional secretion, and CB1R was expressed decreasingly, and endocannabinoid hydrolase was expressed increasingly. We can conclude that the changes of cannabinoid receptor and endocannabinoid hydrolase participate in the regulation of HPA axis secretion function in the T2DM pathogenic process. |
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