Expression of α-smooth muscle actin in the lateral ventricle wall of spontaneous hydrocephalus animals.

Hydrocephalus is a brain disorder in which cerebrospinal fluid accumulates in the ventricles. Our previous study identified aberrant α-smooth muscle actin (α-SMA) expression in the lateral ventricle lining of hydrocephalic coiled-coil domain containing 85c (Ccdc85c) mutant rats. Here, we investigate α-SMA expression in spontaneous hydrocephalic rat, dogs, cats, and cattle. Immunohistochemistry revealed distinct α-SMA expression in a hydrocephalic rat (3 weeks old) and cattle (9 months old), but not in dogs or cats, suggesting species-specific differences. Co-expression of α-SMA and vimentin was observed in cattle, along with strong glial fibrillary acidic protein (GFAP) and vimentin expression in rat and cattle, particularly in ependymal cells. These findings suggest that α-SMA expression in the lateral ventricle wall of hydrocephalic rat and cattle reflects a reactive or pathological response, potentially linked to gliosis.