Immunohistochemical Investigation of p53, Bax and NSE; the Link between Energy Metabolism and Cell Cycle Dysregulation in Degenerating Cells of the Cerebellar Cortex

Background: The cerebellum, also called the little brain is an organ concerned with regulation of movement and other associated motor functions. It is believed to be phylogenetically one of the oldest parts of the brain. It accounts for one tenth of the brain volume and contains approximately 50% of the total brain neuron. Damage to the cerebellum is major factor involved in the progression of movement disorders.

Aim: To investigate possibility of selective neuronal vulnerability in neurotoxicity and the etiology of neurodegenerative diseases especially those involving movement disorders originating from the cerebellum.

Method: F1 Generation adult Wistar rats were treated with 20 and 10 mg/Kg BW of potassium cyanide (KCN), the cerebellar cortex was harvested and processed for immunohistochemistry of cell cycle markers (anti-p53 and anti-Bax) and the neuronal glycolytic pathway marker; Neuron Specific Enolase (anti-NSE). Antigen retrieval method was used specifically as peroxidase anti peroxidase reaction (PAP). The reaction was developed using a polymer 3’3’Diaminobenzidine tetrachloride (DAB), intensified in Methenamine Silver and counterstained in Hematoxylin.

Results: Cyanide toxicity induced apoptosis in the cerebellum via a pathway involving Bax in mitochondria dysregulation (mitochondria apoptotic signaling) and a cytoplasmic pathway involving p53 (a nucleolase). The NSE expression level also indicates associated metabolic dysregulation with alteration in expression of cell cycle proteins.

Conclusion: Cyanide toxicity induced cell death in the cerebellar cortex by metabolic alteration (NSE) and ROS formation. The expression of Bax and p53 showed that apoptosis was triggered via a mitochondria/Bax dependent, p53 related apoptotic pathway.