Title : Pharmacological evaluation of bombesin like peptides in sepsis-induced cerebral injury, inflammation, and cognition in mouse model
Abstract:
Background: Sepsis is a life threating condition characterized by organ dysfunction resulting from the body's inappropriate response to infection. Neuromedin B is a decapeptide consisting of 30-32 amino acids, isolated from porcine spinal cord, and serves as a mammalian analogue of the Bombesin family.
Aim: This study is designed to explore the therapeutic potential of Neuromedin B (NMB) in sepsis-induced cerebral injury and cognitive decline in mice.
Material and Methods: We employed the CLP model, recognized as the gold standard, to induce sepsis-associated brain injury in mice. After CLP induction, mice received NMB for six consecutive days at doses of 16, 32, and 64 nmol/kg. An FAK inhibitor (PND-1168) was administered at a dosage of 30 mg/kg, alongside a Src inhibitor (SU-6656) at a dosage of 4 mg/kg, to elucidate the downstream pathway. Between days 7 and 12, we evaluated behavioral changes through various parameters, including the Open Field Test (OFT), inhibitory avoidance, recognition memory, and spatial learning and memory assessed via the Morris Water Maze. We used calorimetric assays to measure the levels of MDA, SOD, and GSH. ELISA was used to measure synaptic proteins, inflammatory markers, apoptotic markers, and neuronal injury markers. We also assess the water content in the mouse brain. We assessed mRNA expression (Fak) and protein expression (pSrc) using qRT-PCR and western blot, respectively. We evaluated structural changes using IHC and H&E staining.
Results: Behavioural outcomes indicated that NMB (16, 32, and 64 nmol/kg) improved memory across aversive, spatial, and emotional domains, as well as locomotion, in a dose-dependent manner. In contrast, Fak (PND-1168; 30 mg/kg) and Src (SU-6656; 4 mg/kg) inhibitors diminished the efficacy of NMB by causing cognitive deficits in CLP mice. Observations show that NMB controls oxidative balance by adjusting the different amounts of SOD, GSH, and MDA that happen after CLP. Markers for inflammation (TNF-α and IL-1β), cell death (caspase 3 and Bcl-2), and nerve damage were lowered after NMB treatment. In addition, NMB raises the levels of the synaptic protein synaptophysin and lowers the amount of water in the brains of mice that have been exposed to CLP. qRT-PCR analysis demonstrated that NMB significantly enhances the mRNA expression of Fak in a dose-dependent manner. Western blot results indicated that the expression of pSrc significantly improved in NMB-treated mice. Conversely, Fak and Src inhibitors negate the protective effect conferred by NMB. IHC staining also shows that GFAP expression is significantly lower in mice that were given NMB.
Conclusion: Thus, it is plausible to believe that NMB may provide some protection against CLP-induced brain damage and cognitive impairment in mice.
