Introduction: Applications of gold nanoparticles (GNPs) in modern life lead to the release of GNPs into the environment, thus representing a potential hazard to human health.
Aim of the work: To evaluate the effect of GNPs on the renal cortex of adult female rats employing different histological and immunohistochemical techniques.
Materials and Methods: Thirty adult female albino rats were divided into three equal groups; Group I (Control), in groups II and group III, GNPs were administered daily as 40μg/kg and 400μg/kg for 14 days, respectively. Specimens were processed for light and electron microscopy, in addition to immunohistochemical staining for tumor necrosis factor-alpha (TNF-α).
Results: GNPs-treated animals showed many hypercellular glomeruli. Most proximal convoluted tubules (PCTs) were severely distorted, their cells showed vacuolated cytoplasm and pyknotic nuclei. Many distal convoluted tubules (DCTs) showed exfoliated cells and some karyolytic nuclei. Some tubules were totally distorted. Dilated congested blood vessels together with extensive mononuclear cellular aggregations were observed. Ultrastructural examination revealed podocytes with small heterochromatic nuclei and interrupted processes with distortion and effacement. Many GNPs resided in the podocytic terminal processes. Some cells of PCTs showed irregular nuclei, variably sized and shaped mitochondria with loss of their basal orientation. Focal areas of rarefied cytoplasm and apical vacuoles were observed. Cells of DCTs showed irregular nuclei and numerous abnormally shaped mitochondria. Irregularly thickened basal lamina and GNPs were clearly observed in their cytoplasm. The immunohistochemical study showed a highly significant increase in TNF-α immunoreaction.
Conclusion: GNPs cause dose-dependent structural changes in renal cortex with various degrees of inflammation.