The Association of Major Depressive Disorder with Activation of NLRP3 Inflammasome, Lipid Peroxidation, and Total Antioxidant Capacity.

Increasing number of studies indicates that chronic inflammation and oxidative stress play an essential role in pathophysiology and some symptoms of major depressive disorder (MDD). In the present study, the inflammasome activity and oxidative stress status in untreated and antidepressant-treated MDD patients were compared to the healthy group. Blood samples were taken from 20 MDD patients receiving treatment, 20 first-episode MDD patients not receiving treatment, and 20 healthy controls. The expression level of NLRP3 and caspase-1 was measured by real-time PCR and the serum TAC and MDA were examined in the patients and the control groups. The results showed that the mRNA level of NLRP3 and caspase-1 genes was significantly elevated in MDD groups compared with that in the healthy volunteers (P < 0.005). The expression level of NLRP3 and caspase-1 has slightly decreased in the treated group compared with that in the untreated one, but it was not a meaningful decrease. Moreover, the serum MDA was significantly higher and TAC statistically was lower in untreated MDD patients compared with those in the healthy control group (P = 0.001, P = 0.001). It can be concluded that NLRP3 inflammasome is upregulated in MDD patients. Statistically significant reduction in the level of TAC along with increased lipid peroxidation was detectable in MDD patient's plasma. In contrast, there was no significant difference between the treated and non-treated groups in terms of oxidative stress (P = 0.6, P = 0.1). Our results suggested that inflammasome signaling pathway is a therapeutic potential for MDD.