Acute toxicity and genotoxicity studies on new melatonergic antidepressant GW117

GW117 induces anxiolytic effects by improving hippocampal functions

GW117 functions as both an MT1/MT2 receptor agonist and a 5-HT2C receptor antagonist. This study aimed to investigate the anxiolytic effects of GW117 through behavioral assessments, including the open field test and novelty-suppressed feeding test (NSFT) within a chronic unpredictable mild stress (CUMS) model. GW117 was administered via oral gavage for 21 days to evaluate its sustained anxiolytic effects, with behavioral tests including the NSFT, the Vogel-conflict test, and the O-maze test. To explore the underlying mechanisms, we performed Western blot analyses to assess the expression levels of BCL2-Associated X (Bax), cleaved caspase-3, B-cell lymphoma-2 (Bcl-2), brain-derived neurotrophic factor (BDNF), and glial fibrillary acidic protein (GFAP). Additionally, BrdU labeling and immunofluorescence staining were used to examine changes in neuronal regeneration and astrocytogenesis. Our results demonstrated that GW117 produced significant anxiolytic effects across all behavioral assays, both in the CUMS model and during long-term administration. Mechanistic studies revealed that GW117 notably increased the expression of BDNF, GFAP, and Bcl-2, while reducing Bax and cleaved caspase-3 levels in the hippocampus of CUMS model rats. Furthermore, the populations of BrdU-positive and GFAP-positive cells were elevated. These findings suggest that GW117 exerts anxiolytic effects, potentially through enhancements in hippocampal function.

Agomelatine ameliorates doxorubicin-induced cortical and hippocampal brain injury via inhibition of TNF-alpha/NF-kB pathway

Side effects of doxorubicin (DOX) are mainly due to oxidative stress, with the involvement of inflammatory and apoptotic mechanisms. Agomelatine (AGO) is a melatonin receptor agonist with antioxidant, anti-inflammatory, and anti-apoptotic features. This study aimed to evaluate the effects of AGO with different doses on DOX-induced neurotoxicity. Rats were divided into four groups as control, DOX (40 mg/kg, intraperitoneal single dose), DOX + AGO20 (20 mg/kg AGO oral gavage for 14 days), and DOX + AGO40 (40 mg/kg AGO oral gavage for 14 days). On day 14, brain tissues were collected for biochemical, histopathological, and genetic examinations. DOX significantly increased malondialdehyde and decreased superoxide dismutase and catalase (CAT) levels. CAT levels were significantly increased only in the DOX + AGO40 group compared to the DOX group (p = 0.040) while other changes in oxidant and antioxidant indicators were insignificant. DOX-induced significant increases in TNF-alpha and NF-κB were reversed following both low and high-dose AGO administration in a dose-dependent manner (p < 0.001 for both doses). Cellular shrinkage, pycnotic change, and vacuolization in apoptotic bodies were apparent in the cortical and hippocampal areas of DOX-treated samples. Both doses of AGO alleviated these histopathological changes (p = 0.01 for AGO20 and p = 0.05 for AGO40). Significantly increased apoptosis shown with caspase-3 immunostaining in the DOX group was alleviated following AGO administration, with additional improvement after high-dose treatment (p < 0.01 for DOX compared to both AGO groups and p < 0.05 for AGO40 compared to AGO20). AGO can be protective against DOX-induced neurotoxicity by antioxidant, anti-inflammatory, and anti-apoptotic mechanisms in a dose-dependent manner.