Abstract
Iodine is a double-edged sword; while essential for thyroid function, excessive intake triggers systemic toxicity. This study evaluated the chronic effects of oral iodine on the liver and brain of thirty guinea pigs over a 60-day period. The animals were divided into: Group I (Negative Control); Group II (Positive Control, receiving potassium iodide at 10 mg/kg); and Group III (Experimental, receiving a 20% iodine solution). The study utilized biochemical assays, H&E staining, and Nissl staining to assess cellular and neuronal integrity. Hepatotoxicity and Metabolic Impairment Biochemical analysis revealed a significant, time-dependent elevation in serum ALT and AST levels, particularly in Group III. Neuro histological Changes and Neuronal Degeneration The central nervous system showed marked vulnerability to chronic iodine exposure, Meningeal vascular congestion, liquefactive cortical necrosis, diffuse neuronal death, and reactive astrogliosis were observed in histopathological analysis of treated animals. Nissl staining additionally showed prominent chromatolysis, consistent with loss of neuronal protein synthesis. The chronic overexposure to iodine precipitates irreversible multi-organ dysfunction by cellular necrosis and metabolic perturbation, with the severity of toxicity being highly dose-dependent and therefore requiring the establishment of strict evidence-based upper intake limits.