Pioglitazone protects against trimethyltin hippocampal injury by reducing pyroptosis, mitochondrial dysregulation and ER stress.

Hippocampus-specific neurotoxic trimethyltin (TMT) is routinely used to mimic a reliable murine phenotype of neurodegeneration as well as cognitive loss and is accordingly appropriate to analyze pathogenesis of the prevalent neurodegenerative disorders, i.e. Alzheimer's disease (AD), and to examine the effectiveness of novel therapeutics. Antidiabetic medication pioglitazone has exhibited neuroprotective effects with promising clinical indications for neurodegeneration-based illnesses. This study was accomplished for studying the neuroprotective effect of pioglitazone against TMT-initiated cognitive decline and allied hippocampal neurodegeneration. For this purpose, rats received intraperitoneal TMT (8 mg/kg) to generate a model of AD-like neurodegeneration and subsequently had oral daily administration of pioglitazone for 3 weeks (20 mg/kg). The acetylcholinesterase inhibitor and certified anti-AD drug donepezil (4 mg/kg) was similarly used as a positive control medicine. Pioglitazone treatment was accompanied by lower cognitive deficits in novel object recognition test and Barnes maze paradigm in addition to mitigation of astrogliosis severity with glial fibrillary acidic protein (GFAP) as its specific indicator and lower CA1 neuronal loss. Furthermore, pioglitazone partially normalized hippocampal factors of oxidative stress and neuroinflammation together with downregulation of pyroptotic parameters comprising caspase 1 and NLR family pyrin domain containing 3 (NLRP3). Moreover, less activity of acetylcholinesterase (AChE) and greater quantity of mitochondrial health-allied factors comprising peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), mitochondrial membrane potential (MMP), mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor γ (PPARγ) were likewise detected after pioglitazone treatment. These advantageous properties of pioglitazone were accompanied by inferior quantity of specific AD-allied markers comprising presenilin1 (PSEN1) and hyperphosphorylated tau (p-tau) as well as downregulation of endoplasmic reticulum (ER) stress, as observed by lower levels of PKR-like ER kinase (PERK), C/EBP homologous protein (CHOP), glucose-regulated protein 78 (GRP78), and inositol-requiring enzyme 1α (IRE1α). While anti-AD donepezil treatment was associated with improvement of cognitive function, however, it was not capable to significantly yield most advantageous effects of anti-diabetic PPARg agonist pioglitazone. This study disclosed the underlying pathways for neuroprotective effect of pioglitazone in TMT neurodegeneration and AD-like phenotype.