Acupuncture reverses behavioral disturbances and testosterone levels in social isolated rats
Creators: name: Dávila-Hernández, Amalia
name: Zamudio, Sergio R.
name: Martínez-Mota, Lucía
name: González-González, Roberto
name: Guzmán-Velázquez, Sonia
Publisher: name: F1000 Research Limited
Year: 2017

description: A growing number of human and animal studies suggest a modulatory role of testosterone in the regulation of emotionality, stress response, and psychiatric disorders, including depressive-like disorders. Acupuncture has been demonstrated to have antidepressant-like effect in humans and ameliorate depression-related behavior in depression models. However, the effect of acupuncture on testosterone and depressive-like behavior remains unknown.<br><br>The objective of the present study was to determine whether the antidepressant effect of acupuncture in an animal model of chronic stress is related to the modulation of the gonadal and adrenal axis in male rats.<br><br>On postnatal day 21, forty Sprague–Dawley male rats were weaned and randomly divided into: social isolation and acu-catgut embedding (SI+AC); social isolation and sham acu-catgut embedding (SI+SA); group housing and acu-catgut embedding (G+AC); group housing and sham acu-catgut embedding (G+SA) with 10 animals in each group. Depression model was established by post-weaning social isolation for 8 weeks. Hypogonadism model was established by orchidectomy at PND 56. In gonadally inctact animals, the surgical procedures did not affect the gonads. In AC groups, surgical suture (acu-catgut) was embedded in Baihui (DU 20), Yintang (Ex 3), Baihui (DM20), Shenshu (BL 23), Pishu (BL 20), Ganshu (BL 18) and Xinshu (BL 15) at PND 77. In Sham groups, the acupoints were punctioned without the embedding thread (SA). Depression-like behavior was evaluated through the Forced swimming test (FST) at PND 98. Testosterone (T) and corticosterone levels in the serum were examined by ELISA at PND 98.<br><br>Results: SI increased immobility and reduced active behaviors in the FST respect to rats raised in a group. OX increased immobility time in G and SI rats. AC significantly reduced the immobility time in SI gonadally intact males, as well as in G and SI OX animals. SI decreased climbing time, on the contrary AC increased climbing time specially in OX animals. AC increased the swimming behavior time in gonadally intact  and OX rats. SI increased corticosterone after exposure of animals to the FST. AC returned corticosterone levels to normal response in gonadally intact animals. SI reduced T levels, AC interferred with T alterations in SI gonadally intact males.<br><br>Discussion: In rodents, social isolation produces depressive behavior, which is associated with alterations in the morphology of the hippocampus and amygdala, as well as disturbances in adrenal and gonadal axes. The hormonal effect of AC in gonadally intact animals, subjected to social isolation, suggests that intervention prevents the dysregulation of these axes subsequent to chronic stress. These effects add to AC actions on hippocampal plasticity and monoaminergic neurotransmission, and altogether would explain the antidepressant-like effects of AC. Interestingly, in conditions of hypogonadism, the antidepressant-like effect of AC does not seem to be related to the adrenal axis regulation, or to the release of T from an extragonadal source. According to the results of active behaviors in the FST, an alternative hypothesis to explain the findings in OX animals is the possible mediation of monoamines stimulated by AC. <br><br>Conclusion: Acupoints stimulation by absorbable suture prevents the effects of social isolation on depressive behavior, which could be related to its actions on the regulation of corticosterone, T and monoamines. Present findings support the use of this type of intervention in the treatment of depression, even in individuals with hypogonadism.