The effect of maternal-induced diabetes on postnatal development of the paraventricular and ventromedial hypothalamic nuclei in albino rats

Background
The hypothalamus regulates body homeostasis by mediating endocrine, autonomic, and behavioral functions. Maternal diabetes constitutes an unfavorable environment for embryonic development.
Aim of the work
The aim of the present study was to detect the effect of maternal-induced diabetes on the structural organization of the paraventricular and ventromedial hypothalamic nuclei during postnatal development.
Methods
In this study, a total of 60 adult female albino rats were used. They were divided into two groups – group I (control group) included 30 adult female rats, and group II (experimental group) included 30 adult female rats in which diabetes was induced by a single intraperitoneal injection of alloxan monohydrate. Hypothalamic specimens of the offspring were studied at day 1, 21 days, and 2 months of age postnatally. Several techniques were used in this study, including light microscopy, which included gallocyanine–chrom–alum staining and the Golgi–Cox method, transmission electron microscopy, and immunohistochemistry. In addition, a morphometric study was carried out to estimate the number of neurons in the paraventricular and ventromedial nuclei.
Results
In the newborn, neurons in the studied hypothalamic nuclei showed presence of darkly stained nuclei. With age, these degenerative changes became more prominent. Marked reduction in the extension and branching of dendrites was observed. Electron microscopic examination of 2-month-old offspring of diabetic mothers showed the presence of chromatin condensation with many damaged mitochondria and a marked reduction in free ribosomes. Examination of the presynaptic terminals making contact with the neurons of the paraventricular and ventromedial nuclei showed marked reduction in synaptic vesicles and damaged mitochondria. In addition, an apparent increase in the number of astrocytes was found, indicating an increase in the expression of glial fibrillary acidic protein. The number of cells per area was highly decreased at 21 days and 2 months of age in the offsprings of diabetic mothers in comparison with the control group.
Conclusion
In conclusion, this study indicates that maternal diabetes affects the development and structure of the ventromedial and paraventricular nuclei. These changes suggest that there should be strict control of diabetes before and during pregnancy.