ultrastructural changes in the sciatic nerve of albino rats after galactose intoxication

ABSTRACT

Eighteen adult male albino rats aged between 9 - 10 weeks with average weight between 300 - 350 g. were used in the current study. The right and left sciatic nerves of three animals were used as a control. The other animals were divided into three groups, each group of 5 animals. Galactose was administered as a baked paste formed of a mixture of galactose and minced wheat grains in a proportion of 40 60% of the body weight. One month after galactose feeding the study showed myelin infolding and bulge of the myelinated nerve axons with increase in the width of the periaxonal space. Some axons showed cytoplasmic vacuoles, degenerated swollen mitochondriae and electron dense glycogen-like bodies. Six months after galactose feeding Schwann cells of the myelinated nerve fibres showed cytoplasmic vacuoles. The myelinated axons showed wider separation of their content of neurofilaments and neurotubules. The inner cellular layer of the perineurium showed large vacuoles and was separated from the adjacent layer by accumulation of oedema. Twelve months after galactose feeding, some of the myelinated nerve fibres showed degeneration and demyelination of their myelin sheaths. Schwann cells showed multiple cytoplasmic processes that wrapped regenerating axons and their basal laminae showed redundancy. There was an accumulation of subperineurial oedema. The unmyelinated nerve fibres during the current study did not show any significant degenerative changes either in the Schwann cells or in the axons. It could be concluded from the present study that-galactose intoxication could lead to degenerative changes in the myelinated nerve fibres of the peripheral nerves. Also it might affect the blood nerve barrier leading to accumulation of the endoneurial oedema. The occurence of the endoneurial oedema could be the main underlying possible cause of such degenerative changes