Expression of chaperonin 60 in the hippocampus of the streptozotocin diabetic rat.

Abstract

Mitochondrial dysfunction and oxidative stress are implicated in the pathological changes observed in the diabetic central nervous system. In this study, using the streptozotocin-induced diabetic rat model we document for the first time the over-expression of a mitochondrial specific stress protein (chaperonin 60) in the CA1/CA3 regions of the diabetic hippocampus in the absence of neurodegeneration. The increase in expression of chaperonin 60 was not observed in the cohort treated with insulin, suggesting that the observed effect was not due to streptozotocin per se but due to the hyperglycaemic state induced by the diabetic state. The expression of chaperonin 60 was also positively correlated with a marker of mitochondrial oxidative stress (manganese superoxide dismutase). We suggest that chaperonin 60 could be an early event marker of mitochondrial dysfunction in the diabetic central nervous system and indeed be neuroprotective in the early stages of hyperglycaemic-induced oxidative stress.