Neuroprotective Effect of Intranasal Breast Milk-Derived Exosomes in a Neonatal Rat Model of Periventricular Leukomalacia.

BACKGROUND

Periventricular leukomalacia (PVL) is a major cause of neurodevelopmental impairment in premature infants and is characterized by inflammation-associated white matter injury. Breast milk-derived exosomes have regenerative and immunomodulatory properties.

METHODS

Experimental PVL was induced in neonatal Sprague-Dawley rats by maternal lipopolysaccharide administration. Animals were assigned to control (n=10), PVL (n=9), PVL + saline (n=10), and PVL + exosome (n=9) groups. Breast milk-derived exosomes were isolated, characterized according to MISEV2018 criteria, and administered intranasally on postnatal days 1, 3, and 5. Histopathological and biochemical analyses were performed on postnatal day 7.

RESULTS

Significant differences were observed among groups in microcystic injury, myelin basic protein (MBP) staining, and tyrosine hydroxylase staining (p<0.05). Exosome treatment reduced microcystic white matter injury and preserved MBP staining intensity compared with untreated PVL groups. Tyrosine hydroxylase staining was also higher in the exosome-treated group. No significant differences were observed in GFAP staining intensity, histopathological inflammation scores, or IL-6 levels. IL-1β and TNF-α showed altered profiles, suggesting immunomodulatory effects. PKH26 labeling demonstrated exosome-associated fluorescence in the frontal cortex and hippocampus after intranasal administration.

CONCLUSIONS

Intranasal breast milk-derived exosomes attenuated white matter injury and preserved markers of myelin and neuronal integrity in experimental PVL, supporting further investigation in larger models with functional outcome assessments. These findings support a potential cell-free neuroprotective strategy for inflammation-associated neonatal brain injury. However, the use of human breast milk-derived exosomes in rats and the absence of long-term functional outcomes warrant further comparative and longitudinal studies before clinical translation.