Neuropathic or systemic chronic intoxication with Karwinskia humboldtiana (Buckthorn) fruit? Histopathological effect in myocardial and skeletal muscle.

In accidental intoxicated animals and humans, Karwinskia humboldtiana (Kh) causes lesions in the central and peripheral nervous system and organs like the kidney, liver, and lung. The objective was to evaluate the histology of myocardium and skeletal muscle after experimental chronic intoxication with mature fruit of Kh in Wistar rat. Twenty-five rats were used and divided into five groups (n = 5): four intoxicated and one control. Kh fruit was ground, dried, sieved, and administered by an orogastric tube. Intoxicated rats received 3.5 g/kg body weight fractionated in 5 doses. Control rats received only water. Animals were euthanized at 24, 48, 58, and 112 days, respectively. Samples of the myocardium and skeletal muscle were obtained and processed for light microscopy evaluation. Morphological analyses were performed, including a microdensitometric analysis. Results showed areas of necrosis in the muscle fibers, fibers with vacuolated cytoplasm, and disorganization of myofilaments, as well as staining variations in both myocardium and skeletal muscle time-depending. Zones with loss of continuity of the external lamina were identified with PAS with the diastase histochemical method. Immunolabeling with specific antibodies demonstrated diminution of actin and desmin myofilaments. The microdensitometric analysis showed a statistically significant difference between the intoxicated vs control group. These findings demonstrate that chronic intoxication of Kh fruit also causes damage in myocardial and skeletal muscle, these alterations will be useful to understand that the toxic effects of Kh fruit in accidently intoxicated humans are systemic, and not only over the nervous system.