Regulatory impact of intermittent fasting on autophagy in high fat diet induced structural and cognitive brain deteriorations in rats

This study investigated whether intermittent fasting (IF) could protect the brains of obese rats from the cognitive damage caused by a high-fat diet (HFD). Obesity is known to impair memory and thinking, partly by disrupting autophagy — the brain's cellular 'housekeeping' process that clears out damaged proteins and organelles. Researchers fed rats a high-fat diet to induce obesity and cognitive decline, then applied IF as a dietary intervention, measuring brain structure, behavior, inflammation, and key autophagy genes. They found that IF significantly reversed HFD-related cognitive deficits, reduced neuroinflammation, and restored a more balanced autophagy profile in both the cerebral cortex and hippocampus. Specifically, IF modulated the expression of autophagy markers including LC3, ATG5, Beclin-1, and p62, and boosted BDNF — a growth factor critical for neuron survival and learning. The findings suggest that autophagy dysfunction is a key mechanism linking obesity to brain deterioration, and that IF may counteract this by reactivating proper cellular clearance. Because this is an animal study, the results are mechanistically informative but cannot yet be directly applied to human clinical practice.

• IF significantly attenuated HFD-induced cognitive impairment as measured by behavioral tests, associated with reduced neuroinflammatory markers in obese rats.
• IF upregulated mRNA expression of pro-autophagic genes LC3 and ATG5, while decreasing immunohistochemical expression of Beclin-1 and p62 in hippocampal and cortical tissue — indicating restoration of autophagic flux rather than mere induction.
• IF increased BDNF (brain-derived neurotrophic factor) levels and improved histological brain architecture in HFD-fed rats, suggesting concurrent neuroprotective and structural benefits beyond autophagy modulation alone.
• A lean fasting control group was included, allowing the authors to distinguish IF effects specific to the obese condition from general effects of caloric restriction in healthy animals.
• The study implicates both the cerebral cortex and hippocampus as key anatomical targets where HFD-induced autophagy dysfunction drives cognitive deterioration, and where IF exerts its rescue effects.

Twenty-four adult male rats were randomly allocated to four groups (n=6 per group): control, lean fasting, HFD-induced obese, and obese with IF intervention. The HFD protocol was used to establish an obesity and cognitive-impairment model, after which IF was applied for the intervention period. Outcomes included behavioral cognitive testing, serum and tissue biochemical assays for oxidative stress and inflammation, BDNF quantification, immunohistochemical staining for Beclin-1 and p62, mRNA expression analysis of LC3 and ATG5, and histological examination of hippocampal and cortical tissue. The specific duration of the HFD induction phase and IF protocol (e.g., 16:8, 5:2, or alternate-day fasting) are not detailed in the abstract.

The study is conducted entirely in male rats, limiting generalizability to females and to humans, in whom hormonal and metabolic responses to both HFD and IF differ substantially. The small group size (n=6 per group) reduces statistical power and increases the risk of false-positive findings, and the absence of dose–response data for IF timing makes it impossible to identify an optimal fasting regimen. The abstract does not report effect sizes or confidence intervals for most outcomes, and the precise IF protocol is unspecified, making replication and comparison with other IF paradigms difficult. Future experiments should test multiple IF schedules, include female animals, extend the intervention to longer time horizons, and ultimately validate findings in human observational or interventional cohorts.

This study extends [§80] by providing a complementary dietary mechanism — intermittent fasting — through which autophagy-linked clearance pathways (LC3, ATG5) can be enhanced to improve cognitive outcomes in a neurodegeneration-relevant model, paralleling the irisin-exercise axis described there. It parallels [§90], which also examines intermittent fasting's biochemical correction of autophagy dysfunction in a metabolic disease context (type 2 diabetes), reinforcing the cross-disease relevance of IF-autophagy interactions. The autophagy flux markers used here (Beclin-1, p62, LC3) directly echo the mechanistic framework discussed in [§38], which dissects how autophagic quality-control machinery responds to cellular stress, lending molecular context to the immunohistochemical findings. The work also complements [§86] by identifying an independent mechanistic pathway — autophagy dysregulation rather than gut microbiota-metabolome disruption — through which HFD drives cognitive decline, suggesting these mechanisms may act in parallel and warrant combined study.

• Irisin-integrin αV/β5 coupling of α-synuclein phagocytosis and clearance
  Directly parallel intervention-autophagy-cognition axis: examines irisin/exercise-driven autophagic clearance of α-synuclein aggregates, providing a mechanistic benchmark against which IF-driven LC3/ATG5 upregulation can be compared across different autophagy-stimulating stimuli.
• 2-TIP QANDLI DIABET PATOGENEZIDA AUTOFAGIYA JARAYONINING ROLI VA INTERVAL OCHLIKNING BIOKIMYOVIY KORREKSIYASI
  Most directly comparable study in this corpus: investigates intermittent fasting's biochemical correction of autophagy in a type-2 diabetes rat model, enabling side-by-side assessment of whether IF-autophagy effects generalise across metabolic disease contexts or are HFD/obesity-specific.
• Mammalian Lysophagy: mechanisms and pathophysiological implications
  Provides essential mechanistic grounding: its detailed account of mammalian lysosomal and autophagic quality-control machinery contextualises the Beclin-1, p62, and LC3 marker changes reported here, helping readers interpret whether IF restored canonical autophagic flux or triggered an alternative pathway.
• Intermittent Theta-Burst Stimulation (iTBS) Improves Motor Coordination and Modulates Neuroinflammation and Autophagy in SCA3/MJD Mice
  Offers a non-dietary comparator for autophagy modulation in a neuroinflammatory setting — iTBS brain stimulation — allowing readers to weigh IF against a physical intervention on shared neuroinflammation and autophagy endpoints.
• FOXO transcription factors in Alzheimer's Disease: balancing neuroprotection and neuronal degeneration
  Examines FOXO transcription factors balancing neuroprotection and degeneration in Alzheimer's disease; since FOXO signalling is upstream of autophagy induction and is sensitive to fasting-related insulin/mTOR changes, this article helps situate the molecular mechanism by which IF may transcriptionally regulate the autophagy genes measured in this study.