engleski

Expression of dendrin in dorsal horn of the spinal cord is increased in stress and regulated by sex hormones

Introduction: Chronic pain is a major neurological disorder that can be manifested differently between sexes. The complex actions of sex hormones may underlie these differences. Dendrin is a protein whose function has been attributed to synaptic plasticity. To date, its expression in the CNS was found exclusively in forebrain structures. The aim of this study was to demonstrate relation between the expression of dendrin in pain processing areas of the spinal cord (SC) after the chronic stress exposure of rats in and its possible dependence on sex hormones. Methods: Sprague-Dawley rats were orchidectomyzed (M-Orhx), ovariectomized (F- Ovx) or sham (M-Sh or F-Sh) operated at the age of 13 month. At the age of 15 months three 10- day- sessions of sham (C) or chronic stress (S) were applied. The animals were sacrificed at the age of 17 and half months. Paraffin embedded segments of spinal cord were used. The anterior thoracic SC tissue was embedded in paraffin and immunohistochemistry protocol was applied for determination and quantification of dendrin expression. Results: We found expression of dendrin in SC, with specificly prominent expression in dorsal horn, laminas I and II and lamina X (around central canal). The highest expression of dendrin in dorsal horn was observed in SC of M- orh-S group, being significantly higher in comparison to M-Orh-C and M-Sh-S groups (P<0.05). Expression of dendrin was significantly higher in F-Sh-S in comparison to F-Sh-C group (P<0.05) ; as well as in F-Sh-S vs. M-Sh-S and F- Ovx-C vs. M-Orh-C (P<0.05). Discussion: Presented results are in agreement with previous studies, that have suggested that estrogens facilitate and testosterone attenuates stress induced hypersensitivity by modulating spinal excitatory and inhibitory glutamatergic receptor expression. Conclusion: Appearance of dendrin in nociceptive areas of SC indicates its important role in pain perception processing. The expression of dendrin (an important factor in synaptic plasticity) in dorsal horn of SC increases due to stress, but this increase appears to be dependent on sex hormones, in particularly being suppressed by testosterone.

chronic stress ; synaptic plasticity ; spinal cord ; dendrin ; pain

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