The Changes Of P2Y₁ Receptor Expression And Secretory Of TNF-α In Cultural Astrocytes Of Spinal Dorsal Horn Induced By Dexamthasone

It is known that pain does harm to health. The spinal dorsal horn plays an important role in nociceptive information transmission from the periphery to central nervous system. While neuronal functioning is altered, there is significant evidence showing that exaggerated pain is regulated by the activation of astrocytes and microglia. More and more data suggest that the activation of spinal cord glia is necessary for the development and maintenance of pathological pain and hyperalgesia.Moreover, envidences have revealed that the development and maintenance of pathological pain has something to do with P2 receptor, which take part in nociceptive information transmission.P2Y₁ receptor express at astrocytes which located in spinal dorsal horn, and activation of P2Y₁ recetor leads to the secretion of TNF-α.Resesrches on dexamethasone have focused on inhibiting inflammatory factor, however mechanism is unknown.Can dexamethasone ihibit the secretion of TNF-αthrough P2Y₁ receptor pathway,and through activating P2Y₁ receptor pathway?This study will use some methods includeing morphology and ELISA to investigate the relationship between dexamethasone and P2Y₁ receptor in cultured rat dorsal horn astrocytes.Methods: Primary dissociated culture of dorsal spinal cord astrocytes were prepared from Sprague–Dawley rats. The changes of P2Y₁ receptor which expressed in cultured dorsal horn astrocytes were observed by using immunohistochemical staining.And to observe the secretion of TNF-αby means of ELISA.Results:Part one:1. To observe the puration of astrocytes by using immunohistochemical staining,and that of tham was more than 98%.2. Dexamethasone (0.01¹00μmol/L) can dose-dependently decrease the expression of P2Y₁ receptor in cultured rat dorsal horn astrocytes;While after RU486 (1000μmol/L) block the glucocorticoid reccptor, the wok resulted from Dexamethasone become weaker. 3. Dexamethasone (0.01¹00μmol/L) can dose-dependently decrease the secretion of TNF-αin cultured rat dorsal horn astrocytes;While after RU486 (100μmol/L) block the glucocorticoid reccptor, the wok resulted from Dexamethasone become weaker.Part two:1. ADPβwhich activates cultured dorsal horn atrocytes can dose-dependently increase the expression of P2Y₁ receptor and the secretion of TNF-α; MRS2179(0.1¹000μmol/L), P2Y₁-specific antagonist, can inhibit increasing of the expression of P2Y₁ receptor and the secretion of TNF-α.2. After ADPβs activated cultured dorsal horn atrocytes, Dexamethasone can dose-dependently the work laeded by ADPβs.Conclusions:1. Dexamethasone decrease the expression of P2Y₁ receptor and the secretion of TNF-α.2. Astrocytes activated by ADPβs can increase the expression of P2Y₁ receptor.3. Dexamethasone can inhibit the expression of P2Y₁ receptor and the secretion of TNF-αin activated astrocyte.In summary, these results suggest that Dexamethasone may increase the pain threshold by inhibiting the expression of P2Y₁ receptor and secretion of TNF-αin cultured dorsal horn astrocytes ;We also provide evidence that Dexamethasone can release the pain threshold by inhibiting the secretion of TNF-α.