Restrain-stress-induced Biochemical and Transmission Electron Microscopic Changes in Albino Rat’s Brain

Abstract

Restrained-stress in adult male albino rats for 24 hours in continuity resulted in increased lipid peroxidation (maximum 37.03% in cerebellum) and 8-fold increase (statistically significant p<0.001in brainstem) of fluorescent pigment intensity. Greater affinity of darkly stained luxol-fast positive Purkinje neurons suggests decreased metabolic activity as a result of stress. TEM revealed an increase in the incidence of pleomorphic electrodense bodies in neurons of different brain parts. In cerebellum, dense bodies even exhibited fingerprint pattern due to engulfment of damaged cytomembranes subsequent to increased lipid peroxidation. The electronluscent vacuoles located either at or near the periphery or inside the electrondense bodies, were likely to represent the digested material consequent upon the action of action of hydrolytic enzymes. The increase in the number of coated and smooth vesicles and abundance of microtubules in the cytoplasm of neurons of stressed rats exhibited ultrastructural features in support of their being involved in the transfer of membranes and membrane-associated molecules in the intracellular compartments. Increase in GERL-like profiles could also be detected in cingulate cortex, hypothalamus, and cerebellum after 24 hours restrain of rats. Interestingly, GERL displayed continuity with different cellular organelles in cerebellum of stressed rats. These findings supported the concept advocated by Paavola that GERL’s lytic enzymes engulf membranes and trapped lysosomes thus producing aggregate type inclusions of electrodense bodies.