MATERIALS AND METHODS: Rats were exposed to d-gal 60 mg/kg/b.wt/day + AlCl3 200 mg/kg/b.wt/day and CA (200, 400 and 800 mg/kg/b.wt/day) and 1 mg/kg/b.wt/day of donepezil for 70 days. Different cognitive paradigms viz. T maze spontaneous alternation, modified elevated plus maze and novel object recognition test, were used to evaluate full lesions of the hippocampus, spatial learning and memory and non-spatial learning and memory respectively. Nissl's staining was used to determine the survival of hippocampus CA1 pyramidal cells, while transmission electron microscopy was used to check the ultrastructural changes.
RESULTS: The results revealed that d-gal and AlCl3 could significantly impair behavior and cognitive functions, besides causing damage to the hippocampal CA1 pyramidal neurons in rats. In addition, it also caused ultrastructural morphological alterations in rat hippocampus. Conversely, co-administration o;f CA, irrespective of the dosage used, alleviated the cognitive impairments and pathological changes in the rats comparable to donepezil.
CONCLUSION: In conclusion the results suggest that CA could protect cognitive impairments and morphological alterations caused by d-gal and AlCl3 toxicity in rats. Biochemical and molecular studies are ongoing to elucidate the probable pharmacodynamics of CA.
Experimental procedure: Thirty six virgin adult female rats (n = 6) were randomly divided into six groups; Group 1-3 were normal control (NC), Sham (SHAM) and ovariectomized group (OVX) respectively whereas group 4-6 were PPD rats forced-fed once daily with distilled water (PPD), fish oil (PPD + FO; 9 g/kg) and Fluoxetine (PPD + FLX; 15 mg/kg) respectively from postpartum day 1 and continued for 10 consecutive days. Rats behaviors were evaluated on postpartum day 10 through open field test (OFT) and forced swimming test (FST), followed by biochemical analysis of NLRP3 inflammasome proteins pathway in their brain and determination of neutrophil to lymphocyte ratio (NLR).
Results: PPD-induced rats exhibited high immobility and low swimming time in FST with increased inflammatory status; NLR, IL-1β and NFкB/NLRP3/caspase-1 activity in their hippocampus. However, administration of FO or fluoxetine reversed the aforementioned abnormalities.
Conclusion: In conclusion, 10 days supplementation with FO ameliorated the depressive-like behaviors in PPD rats by targeting the NFкB/NLRP3/caspase-1/IL-1β activity. This has shed light on the potential of NLRP3 as a therapeutic target in treatment of PPD in rats.