2026 ECNP Congress

EP02-2038

Remyelinating, anti-inflammatory and antioxidant effects of propentofylline in a gliotoxic demyelinating model in rats

Eduardo Bondan — M.F. Martins, M. Paes de Barros · University Paulista, Graduate Program in Experimental and Environmental Pathology, São Paulo, Brazil

2026 ECNP Congress

Propentofylline (PPF) is a methylated xanthine compound that diminishes the activation of microglial cells and astrocytes, which are cells strongly associated with many neurodegenerative and demyelinating diseases. PPF has also been proposed to increase antioxidant defenses and thus preventing oxidative damage in neural tissue [1] [2]. Ethidium-bromide (EB) injection into the central nervous system (CNS) is commonly used as an experimental demyelinating model inducing local oligodendroglial and astrocytic death, which results in primary demyelination, blood-brain barrier, glia limitans disruption and Schwann cells invasion [3] [4].

The aim of this study was to evaluate if PPF had the capacity of affecting glial cells behaviour during the process of demyelination and remyelination following EB gliotoxic injury. It also aimed to evaluate PPF anti-inflammatory and antioxidant effects in Wistar rats exposed to a gliotoxic agent from 7 to 31 days.

Sixty Wistar rats were divided into four different groups receiving 10 microlitres of 0.1% EB or 0.9% saline solution into the cisterna pontis and treated or not with the xanthine. PPF treatment was done using 12.5 mg/kg/day (intraperitonial route) during 31 days. Rats were euthanized at 7, 15 and 31 days after EB injection and brainstem sections were collected and processed for light and transmission electron microscopy studies. Results from both groups were compared by using a semi-quantitative method developed for documenting in semithin sections the extent and nature of remyelination of demyelinated lesions. Plasma levels of IL-1β and TNF-α were measured by ELISA. Brainstem samples were used to determine thiobarbituric acid reactive substances (TBARS) levels, catalase and glutathione reductase (GR) activities, reduced (GSH) and oxidized glutathione (GSSG) contents, GSH/GSSG ratio and iron content. The total antioxidant capacity of the nervous tissue was analyzed by the ferric reducing activity method (FRAP).

Results showed that PPF administration after EB injection significantly increased both oligodendroglial and Schwann cell remyelination at 31 days (mean remyelination scores of 3.67±0.5 for oligodendrocytes and 1.27±0.49 for Schwann cells) compared to untreated animals (scores of 3.19±0.57 and 0.90±0.33, respectively). The bulk of the data here demonstrates that, after 7 days of EB treatment, TBARS levels were 2-fold higher in the rat CNS than in control, reaching a maximum of 2.4-fold within 15 days. After 31 days of EB treatment, lipoperoxidation in CNS was still 65% higher than that in the control. PPF treatment limited the progression of lipoperoxidation in EB-oxidized CNS (76% lower than in the EB-treated group after 15 days). Most of these effects were associated with PPF-induced activity of GR in the brainstem. The EB+PPF group showed 59% higher GR activity than that of the EB or control groups within 7 days. Plasma IL-1β and TNF-α levels were increased at 7 and 15 days in the EB-group, but not in the EB+PPF group.

In summary, we observed that PPF improved remyelination, decreased pro-inflammatory cytokine levels and improved the thiol-based antioxidant defenses in the rat brainstem by the induction of the enzymatic activity of GR, which diminished lipid oxidation progression and rebalanced the redox status in the CNS.

References

  1. Franco, R., Oñatibia-Astibia, A., Martínez-Pinilla, E., 2013. Health benefits of methylxanthines in cacao and chocolate. Nutrients 5, 4159-4173.
  2. Janitschke, D., Lauer, A.A., Bachmann, C.M., Grimm, H.S., Hartmann, T., Grimm, M.O.W., 2021. Methylxanthines and neurodegenerative diseases: An update. Nutrients 13, 803.
  3. Bondan, E.F., Lallo, M.A., Sinhorini, I.L., Pereira, L.A., Graça, D.L., 2000. The effect of cyclophosphamide on brainstem remyelination following local ethidium bromide injection in Wistar rats. J. Submicrosc. Cytol. Pathol. 32(4), 603-612.
  4. Bondan, E.F., Monteiro Martins, M.D.F., 2013. Cyclosporine improves remyelination in diabetic rats submitted to a gliotoxic demyelinating model in the brainstem. Microsc. Res. Tech. 76, 714-722.