Torasemide Improves the Propionic Acid-Induced Autism in Rats: A Histopathological and Imaging Study

Autism spectrum disorder is a neurodevelopmental disease in which impaired social behaviors, impaired sociality, and restricted and repetitive behaviors are seen. Bumetanide is a loop diuretic that inhibits Na⁺-K⁺-2Cl^- cotransporter 1 and it is currently used in clinical phase studies in patients with autism spectrum disorder. In present research, it is purposed to demonstrate the beneficial effects of torasemide which is another Na⁺-K⁺-2Cl^- cotransporter 1 inhibitor on an experimental autism model induced with propionic acid by providing imaging and brain tissue investigations.

Male Wistar rats were used in the present study (n = 30). Propionic acid of 250 mg/kg/day was administrated intraperitoneally in rats to induce autism for 5 days. Three groups were created for present study as follows: group 1, normal control (n = 10); group 2, propionic acid and saline given group (n = 10); group 3, propionic acid + tora-semide-administrated group (n = 10).

Torasemide group scored higher on behavioral tests compared to saline group. The brain levels of malondialdehyde, tumor necrosis factor-alpha, interleukin-2, interleukin-17, and Nuclear Factor kappa B (NF-κB), Glial fibrillary acidic protein (GFAP) were remarkably higher in propionic acid + saline group. In histopathology assessments, torasemide group had higher neuronal count of Cornu Ammonis 1, neuronal count of Cornu Ammonis 2 in hippocampus, and Purkinje cells in cerebellum. GFAP immunostaining index (Cornu Ammonis 1) and cerebellum were lower in torasemide group. Magnetic resonance spectroscopy revealed that mean lactate value was higher in propionic acid + saline group compared to torasemide group.

Our experimental results showed that torasemide might enhance gamma-aminobutyric acid activity. Torasemide can be considered another promising Na⁺-K⁺-2Cl^- cotransporter 1 inhibitor in the treatment of autism with a longer half-life and less side effects after further studies.