Abstract:
Lithium carbonate is the first line of treatment for bipolar disorder. With its narrow therapeutic index and prolonged therapeutic doses, it causes multiple toxic effects. Cardiotoxicity is one of the serious toxicities induced by lithium treatment. Silybum marianum; an Asteraceae plant; with Silymarin as its major active constituent, has antioxidant, anti-inflammatory, and immunomodulatory properties. To assess the ameliorative effect of Silybum marianum extract “Milk thistle" on the histopathological changes of the cardiac muscle caused by lithium in adult male albino rats, using histological and immunohistochemical techniques. Twenty-Four adult male albino rats were equally randomized into 4 groups and received all treatments by oral gavage for 4 weeks. Group I (control) received distilled water. Group II received Silybum marianum extract (200 mg/kg/day). Group III received Lithium carbonate (50 mg/Kg). Group IV, Lithium carbonate concomitant with Silybum marianum extract was given. All animals were sacrificed after 4 weeks by decapitation. Prepared sections were subjected to hematoxylin and eosin stain, Mallory's trichrome stain, iron hematoxylin, and KI-67 immunohistochemistry. lithium-induced widely disorganized and separated cardiac muscle fibers with pyknotic nuclei, without visible striations, increased collagen deposition and showed negative Ki-67 nuclear immune reaction. The use of Silybum marianum extract “Milk thistle" reversed cardiac muscle fibers alterations, decreased collagen amount, and restored Ki-67 nuclear immune reaction. Silybum marianum extract “Milk thistle" protects against lithium-induced cardiotoxicity in rats.