Effect Of Pineal Gland And Melatonin On CRH Neuron Of Rat Hypothalamus

Objective To study the morphological and functional effect of pinealectomy(PX) on CRH neurons in paraventricular nucleus of rat hypothalamus as well as thefunction of melatonin supplementation, enrich the research of the effect of pinealbody and melatonin on hypothalamic-pituitary-adrenal(HPA) axis,provide theoreticalevidence of the effect of pineal body and melatonin on immune function andimmune-associated disease such as tumor and autoimmune disease.Methods â‘ In situ hybridization(ISH) was applied to observe the changes ofhypothalamic CRHmRNA positive cells after PX and melatonin supplementation; â‘¡Immunohistochemistry(IHC) was used to observe the changes of CRH positive cellsin hypothalamus and CRH staining in median eminence of neurohypophysis after PXand melatonin supplementation; â‘¢ELISA was applied to detect the changes of CRHconcentration in serum after PX and melatonin supplementation.Results â‘ Compared to sham group, ISH and IHC of rat hypothalamic CRHshow positive cells numbers increase, positive areas enlarge and average gray scaledecreases, which reveals the expression of hypothalamic CRH neurons enhances afterPX; â‘¡The enhancement of ISH and IHC of hypothalamic CRH in PX rats aftermelatonin supplementation dose-dependently recovers, but it can't return to be normaleither in high dose group or in low dose group and either at 4th week or at 8th week;â‘¢IHC of CRH in median eminence of neurohypophysis shows positive areas enlargeand average gray scale decreases, which reveals the releasing of CRH fromhypothalamic CRH neurons increases; â‘£ELISA of CRH in serum shows thedifferences of CRH concentrations among all groups are not significant, whichindicates PX and melatonin supplementation have no significant effect on CRH levels. Conclusion PX induces the synthesizing and releasing of CRH by CRHneurons increase, activates HPA axis through hypophyseal portal system, thenmelatonin supplementation can partly reverse the abnormality, which indicates pinealbody is one of the key factors to maintain the structural and functional stablity ofneuroendocrine-immune network...