Long term evaluation of morphometric and ultrastructural changes of testes of alloxan-induced diabetic rats

Amélia Arcângela Teixeira Trindade,Antônio Caetano Pereira Simões,César Tadeu Spadella,Célia Sperandeo Macedo,Reinaldo José Silva

doi:10.1590/s0102-86502013000400005

Abstract

To evaluate in a long term the morphometric and ultrastructural changes in seminiferous tubules (ST) of normal and diabetic rats, and to correlate any changes with animal age and diabetes duration. Sixty male Wistar rats, three months-old, were randomly divided into two groups: 30 non-diabetic controls (N) and 30 alloxan untreated diabetic (D). After one, six and 12 months of follow-up or diabetes induction rats were sacrificed and the testes examined. Morphometric measures of the ST were performed by digital imaging analysis. ST ultrastructure was analyzed by transmission electron microscopy. Sustained hyperglycemic state was observed in all diabetic rats throughout the study. Serum testosterone was also significantly decreased in these animals. The diameter, total area, epithelium area and epithelium thickness of ST were lower and tubular density was higher in diabetic animals. Diabetic rats also showed ultrastructural changes compromising the whole testis including germ-, Sertoli-, and Leydig cells, and also the mithocondria and cellular nuclei. Most frequent of these consisted of vacuolization and/or accumulation of lipid droplets and electron dense dark material in cell cytoplasm and/or in membranes, cellular degeneration, and apoptosis. Non-diabetic control rats also showed testicular lesions that resemble to the diabetic lesions, although much less severe and with later onset in life of these animals. Histopathological changes observed in testes of normal and diabetic rats are closely related to the animal age and/or duration of the hyperglycemic state, being progressively more severe in animals sacrificed belatedly. These changes may play an important role in male infertility observed in diabetic subjects.

Highlights

Diabetes Mellitus (DM) is a chronic disease that affects millions of people worldwide and is associated with high morbidity and mortality[1,2].Abnormal sexual function in diabetic subjects suggests that the male gonads, like the kidneys, vessels, eyes, and nerves may be affected by DM
Besides that the reported abnormalities are conflicting because studies have not always used rat samples matched for age and duration of exposure to the hyperglycemic state considered important factors to determine the severity of testicular lesions
The left testis of four normal non-diabetic rats and four untreated diabetic rats from each subgroup of animals, sacrificed at one, six and 12 months of follow-up or diabetes duration, was random cut into cylindrical pieces of 1mm thick, fixed in 2.5% glutaraldehyde in phosphate buffer, pH 7.4 for two hours (0°C), post-fixed in 1% osmium tetroxide, washed in distilled water, Non-diabetic control rats (N) had clinical and laboratory parameters compatible with those observed in animals of same strain and age at one, six and 12 months of follow-up

Summary

Introduction

Abnormal sexual function in diabetic subjects suggests that the male gonads, like the kidneys, vessels, eyes, and nerves may be affected by DM. The aim of this study was to assess the histopathological abnormalities of ST, and to correlate any changes with animal age and diabetes duration over a long period of follow-up up to 12 months of diabetes and 15 monthsold. We hope this knowledge can fill the gaps of the literature

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