Microglial activation underpins the methotrexate (MTX)-induced neurotoxicity; however, the precise mechanism remains unclear. This study appraised the potential impact of apigenin (Api), a neuroprotective flavonoid, in MTX-induced neurotoxicity in rats in terms of microglial activation through targeting the miR-15a/Rho-associated protein kinase-1 (ROCK-1)/extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Male Sprague Dawley rats were randomly divided into 4 groups: Normal control (saline i.p. daily and i.v. on days 8 and 15); Api control (20 mg/kg, p.o.) daily for 30 days; MTX-alone (75 mg/kg, i.v.) on days 8 and 15, then four i.p. injections of leucovorin (LCV): 6 mg/kg after 18 h, then three doses (3 mg/kg) every 8 h post-MTX; and Api co-treated (20 mg/kg/day, p.o.) throughout the model for 30 days, with administration of MTX and LCV as in group 3. MTX administration elevated hippocampal ionized calcium-binding adaptor protein-1 (Iba-1) immunostaining, indicating microglial activation. This was accompanied by neuroinflammation, oxidative stress, and enhanced apoptosis manifested by elevated hippocampal interleukin-1β, malondialdehyde, and caspase-3, and decreased reduced glutathione levels. Concurrently, abated miR-15a expression, overexpression of its target ROCK-1, diminished downstream ERK1/2 and cAMP response element-binding protein (CREB) phosphorylation, and decreased hippocampal brain-derived neurotrophic factor (BDNF) levels were observed. Api mitigated the MTX-induced neurotoxicity by reversing the biochemical, histopathological, and behavioral derangements tested by novel object recognition and Morris water maze tests. Conclusively, Api lessens MTX-induced neuroinflammation, oxidative stress, and apoptosis and boosts cognitive function through inhibiting microglial activation via modulating the miR-15a/ROCK-1/ERK1/2/CREB/BDNF pathway. Graphical Abstract Graphical abstract showing the effects of methotrexate and apigenin co-treatment in MTX-induced neurotoxicity model. On the left, methotrexate (MTX) administration to rats resulted in hippocampal miR-15a downregulation, which triggered an enhanced expression of its target ROCK-1, consequently inhibiting the downstream ERK1/2/CREB/BDNF pathway, instigating a state of microglial activation, neuroinflammation, oxidative stress, and apoptosis. On the other hand, apigenin (Api) co-treatment restored miR-15a, inhibited ROCK-1 expression, and activated the ERK1/2/CREB/BDNF pathway, leading to diminished hippocampal microglial activation, neuroinflammation, and apoptosis, and restoration of the redox balance, along with improvement in memory and cognitive function of the MTX-treated rats.

Methotrexate (MTX) is a widely used neurotoxic drug with broad antineoplastic and immunosuppressant spectra. However, the exact molecular mechanisms by which MTX inhibits hippocampal neurogenesis are yet unclear. Dexmedetomidine (Dex), an α2-adrenergic receptor agonist, has recently shown neuroprotective effects; however, its full mechanism is unexplored. This study investigated the potential of Dex to mitigate MTX-induced neurotoxicity and memory impairment in rats and the possible role of the miR-15a/ROCK-1/ERK1/2/CREB/BDNF pathway. Notably, no former studies have linked this pathway to MTX-induced neurotoxicity. Male Sprague Dawley rats were placed into four groups. Group 1 received saline i.p. daily and i.v. on days 8 and 15. Group 2 received Dex at 10 μg/kg/day i.p. for 30 days. Group 3 received MTX at 75 mg/kg i.v. on days 8 and 15, followed by four i.p. doses of leucovorin at 6 mg/kg after 18 h and 3 mg/kg after 26, 42, and 50 h. Group 4 received MTX and leucovorin as in group 3 and Dex daily dosages as in group 2. Bioinformatic analysis identified the association of miR-15a with ROCK-1/ERK1/2/CREB/BDNF and neurogenesis. MTX lowered hippocampal doublecortin and Ki-67, two markers of neurogenesis. This was associated with the downregulation of miR-15a, upregulation of its target ROCK-1, and reduction in the downstream ERK1/2/CREB/BDNF pathway, along with disturbed hippocampal redox state. Novel object recognition and Morris water maze tests demonstrated the MTX-induced memory deficiencies. Dex co-treatment reversed the MTX-induced behavioral, biochemical, and histological alterations in the rats. These neuroprotective actions could be partly mediated through modulating the miR-15a/ROCK-1/ERK1/2/CREB/BDNF pathway, which enhances hippocampal neurogenesis.

One advantage of exploring the human DNA (De-oxyribonucleic acid) is the revelation of its contribution to many human diseases. In result of exploring the DNA, there were specific genes in specific chromosomes in the DNA that reveal Alzheimer's Disease (AD). Prognosis of AD helps in slowing down the progression of the disease considerably which is our main goal. AD is an irreversible progressive disease in the brain that slowly causes decline in the memory affecting the patient's life. AD can be detected by screening the WGS (Whole Genome Sequence) to search in specific genes that are responsible for detecting AD or by finding the mutations that happens in the SNPs (Single-Nucleotide Polymorphism) in these specific genes. This research applies two different approaches to study and analyze the DNA and compares them to each other to determine the most suitable approach regarding detecting AD. A dataset was imported and accommodated from The Alzheimer's Disease Neuroimaging Initiative (ADNI) used to implement our research. Our research obtained that using SNPs in studying and analyzing AD is faster and more reliable than using WGS.

Dexmedetomidine (Dex), an α2‐adrenergic receptor agonist, and apigenin (Api), a naturally occurring bioflavonoid, have recently shown neuroprotective effects in experimental models of methotrexate (MTX)‐induced neurotoxicity; however, the impact of their combined administration has not yet been elucidated. This study investigated the effects of Dex on microglial activation, neuroinflammation, and apoptosis, and the role of Api in hippocampal neurogenesis, along with its combined effects via the miR‐15a/ROCK‐1/ERK1/2/CREB/BDNF signaling cascade. Male Sprague Dawley rats were randomly assigned into: a normal control group, Dex and Api‐control groups, which received Dex or Api daily for 30 days, an MTX‐only group that received MTX and leucovorin (LCV), Dex or Api cotreated groups received either Dex or Api with MTX and LCV, and a Dex + Api cotreated group received both drugs with MTX and LCV. Dex improved cognitive function by attenuating microglial activation. Api mitigated hippocampal neurogenesis, as shown by decreased Ki‐67 and doublecortin (DCX) expression. Compared with Dex or Api alone, the combined treatment had more favorable effects on novel object recognition (NOR), miR‐15a, ROCK‐1, ERK1/2, histopathological changes, and Ki‐67 neurogenesis marker over Api or Dex monotherapy, and improved CREB/BDNF signaling over Dex alone. However, no additional favorable effects on microglial activation, redox balance, IL‐1β, or apoptosis were observed. The combination of Dex and Api exhibits more pronounced neuroprotective effects by potentiating modulation of the miR‐15a/ROCK‐1/ERK1/2/CREB/BDNF signaling cascade, improving cognitive behavior, and enhancing hippocampal neurogenesis.