RESUMEN
BACKGROUND: The aim of this study was to investigate ultrastructural and apoptotic changes occurring in the kidneys in fasting individuals and to examine the effects of histamine treatment at the electron-microscopic and immunohistochemical levels. METHODS: Eighteen adult Wistar male rats were randomly divided into three groups (n=6 for each). Control group (1), fasting group (12 h) (2), and fasting+histamine injection (0.5 mg/kg) (3) group. Expression of caspase-3 and caspase-9 was determined in the tissue sections using immunohistochemical techniques. Quantitative data were obtained using H-SCORE, and statistical evaluations were then performed. The ultrastructure of the kidney tissues was examined using transmission electron microscopy. RESULTS: Weak caspase-3 and caspase-9 expression was observed in the renal tubules and glomeruli in the control group, while immunoreactivity was more intense in the fasting group (p<0.05). In the fasting+histamine group, caspase-3 and caspase-9 immunostaining was significantly positive in both renal tubules and glomeruli (p<0.05). At electron microscopic evaluation, degenerative changes were seen in the glomeruli of the fasting group, as well as partial vacuolization and disruption at the basal foldings in the tubular epithelial cells. In the fasting+histamine group, in addition to significant dilatation of all glomerular capillaries, there were degenerative changes in all tubular and canalicular epithelial cells in the proximal tubules. CONCLUSIONS: Fasting, an important metabolic stress factor, accompanied by histamine treatment may cause significant disruptions in the kidneys, particularly in the glomerular capillaries and proximal and distal tubules (Tab. 1, Fig. 2, Ref. 34).