Catalpol promotes oligodendrocyte survival and oligodendrocyte progenitor differentiation via the Akt signaling pathway in rats with chronic cerebral hypoperfusion

• Catalpol reduces inflammation of white matter after chronic cerebral hypoperfusion.
• Catalpol attenuates oligodendrocyte apoptosis and myelin damage after hypoperfusion.
• Catalpol promotes oligodendrocyte progenitor differentiation after hypoperfusion.
• Beneficial effects of catalpol are related to the activation of Akt pathway.
• These results suggest that catalpol has potential use for cerebrovascular diseases.

Chronic cerebral hypoperfusion is thought to induce white matter lesions (WMLs), which contribute to cognitive impairment. Although inflammation and oligodendrocyte apoptosis are believed to be involved in the pathogenesis of WMLs, effective therapies have not been identified yet. This study investigated whether catalpol, an iridoid glycoside, can alleviate WMLs by promoting oligodendrocyte survival and oligodendrocyte progenitor differentiation via the Akt signaling pathway in rats with chronic cerebral hypoperfusion. A rat model of chronic cerebral hypoperfusion was created through permanent occlusion of bilateral common carotid arteries. Catalpol (5 mg/kg) or saline was intraperitoneally administered daily for 10 days following the operation. On the 30th day after surgery, inflammation, oligodendrocyte apoptosis, and myelin damage in the ischemic white matter were more severe and evident than in the sham control group. Treatment with catalpol significantly suppressed white matter inflammation and attenuated oligodendrocyte apoptosis and myelin damage. The expression of phosphorylated Akt (p-Akt) and the number of mature oligodendrocytes were also markedly increased by catalpol treatment, and these effects were reversed by the PI3K inhibitor LY294002. In conclusion, catalpol attenuates hypoperfusion-induced WMLs by promoting oligodendrocyte survival and oligodendrocyte progenitor differentiation through the Akt signaling pathway. Our results suggest that catalpol may be a candidate for treating cerebrovascular WMLs.