A HISTOPATHOLOGIC AND HISTOMORPHOMETRIC STUDY ON THE HIPPOCAMPUS OF STZ-INDUCED DIABETIC ALBINO RATS

Muhamed Faizal and Aijaz Ahmed Khan*

ABSTRACT

Aim of the study: The chronic hyperglycemia has been associated with dysfunction of various part of brain resulting into cognitive defects, alteration of behavior, memory and emotion which is possibly due to its harmful effect of on the neurons of the hippocampus. Therefore, the current study was aimed to look for the alteration on the histological and histomorphometric parameters of discrete parts of hippocampus. Material and methods: After clearance from the Institutional Animal Ethical Committee, 36 adult rats were divided into six groups of six rats each having control and diabetic groups. Diabetes was induced with streptozotocin (60 mg/kg; i.p.). Rats having blood glucose >250 mg/ dl were considered as diabetic. At the end of each experiment rats were euthanized by deep ether anesthesia and blood samples were collected for biochemical analysis. Tissues were fixed in Karnovsky fixative and processed for paraffin sectioning. Routine and special stained sections were studied under the light microscope and relevant images were recorded for histological and histomorphometric analysis. Results: It was observed that prolonged hyperglycemia was associated with increased serum creatinine and reduced serum total protein. There was obvious reduction of neuronal density in granular layer of dentate gyrus and CA3 pyramidal neuron in conjunction with remarkable increase in the collagen of tunica adventitia of hippocampal blood vessels and choroid plexus. Conclusion: These findings suggest that hyperglycemia-induced neuronal loss and perivascular excessive deposition of collagen may constitute important contributing factor in the development of diabetes-related memory alteration, depression and cognitive impairments.

Keywords: CA3, Collagen, Dentate gyrus, Diabetes, Hippocampus, STZ-induced.