Sulphur-Rich Protein Supplementation Reverses Motor Impairment and Muscle Atrophy in a Rat Model of Konzo

Background: Konzo is a neurological disorder caused by prolonged consumption of poorly processed bitter cassava, leading to upper motor neuron damage and spastic paralysis. Nutritional deficiency, particularly low sulphur amino acids, exacerbates cyanide toxicity. This study evaluated the effects of bitter cassava and dietary rehabilitation on body weight, motor performance, muscle mass, and cerebral cortex histology in Wistar rats. Methods: Twenty-five female Wistar rats were randomly assigned to five groups (n=5): control, cassava only, cassava + animal feed, cassava + eggshell and brown beans, and eggshell and brown beans only. Rats were fed for four weeks, with body weight measured weekly. Motor function was assessed using the single-pellet reach-to-grasp task. Muscle wet weight (biceps and flexor carpi radialis) was determined post-dissection, and cerebral cortex histology was analyzed using Nissl staining. Data were analyzed with ANOVA and Tukey’s post hoc test (p < 0.05). Results: Cassava-only rats showed weight loss (−2.94%), decreased reach-to-grasp success (46.92 ± 5.07%), and mild muscle atrophy. Dietary supplementation improved outcomes: cassava + animal feed rats gained +9.77% body weight and showed enhanced motor performance (+8.11%), while cassava + eggshell and brown beans rats demonstrated +12.13% improvement in reach-to-grasp and increased muscle mass (biceps: 0.20 ± 0.02 g; flexor carpi radialis: 0.20 ± 0.01 g). Histology revealed disorganized cortical layers, pyknotic pyramidal cells, and chromatolysis in cassava-only rats, whereas amino acid supplementation largely restored cortical cytoarchitecture. Conclusion: Poorly processed bitter cassava induces neurotoxicity, motor deficits, and muscle atrophy in rats. Sulphur amino acid-rich diets mitigate these effects and promote neuronal restoration. Proper cassava processing and dietary protein supplementation are crucial to prevent Konzo.