Altered renal morphology in transgenic mice with cholecystokinin overexpression.

Although cholecystokinin is a regulatory peptide with a predominant role in the brain and the gastrointestinal tract, there is an increasing evidence for its role in the kidney. The aim of this study was to reveal morphological changes in the structure of kidney of mice with cholecystokinin overexpression by means of light, transmission and scanning electron microscope, and atomic force microscopy. Using immunohistochemistry the expression of important basement membrane proteins collagen IV, laminin and fibronectin, as well the distribution of cholecystokinin-8 in the renal structures was evaluated. The altered morphology of kidneys of mice with cholecystokinin overexpression was seen by all microscopic techniques used. The renal corpuscles were relatively small with narrow capsular lumen. The basement membranes of renal tubules were thickened and the epithelial cells were damaged, which was more pronounced for distal tubules. Characteristic feature was the increased number of vesicles seen throughout the epithelial cells of proximal and especially in distal tubules reflecting to the enhanced cellular degeneration. The relative expression of laminin but not collagen IV in the glomerular basement membrane was higher than in the tubular basement membranes. The content of fibronectin, in opposite, was higher in tubular membranes. Cholecystokinin-8 was clearly expressed in the glomeruli, in Bowman's capsule, in proximal and distal tubules, and in collecting ducts. Ultrastructural studies showed irregularly thickened glomerular basement membranes to which elongated cytopodia of differently shaped podocytes were attached. As foot processes were often fused the number of filtration pores was decreased. In conclusion, cholecystokinin plays important role in renal structural formation and in functioning as different aspects of urine production in mice with cholecystokinin overexpression are affected-the uneven glomerular basement membrane thickening, structural changes in podocytes and in filtration slits affect glomerular filtration, while damaged tubular epithelial cells and changed composition of thickened tubular basement membranes affect reabsorption.

Helicobacter pylori substantially increases oxidative stress in indomethacin-exposed rat gastric mucosa.

Helicobacter pylori (H. pylori) often play an important role in the pathogenesis of gastritis, peptic ulcer, and probably also gastric cancer. Reactive oxygen species (ROS) produced by this bacterium may be one of the crucial factors whereby oxidative stress can play a role in the pathogenesis of ulcer disease. The aim of this study was to assess ROS activity and glutathione redox status, a principal cellular redox sensor, in H. pylori-associated indomethacin-induced gastric ulcers in rats. Gastric lesion was produced by intragastric administration of indomethacin (7 mg/kg) for three days followed by administration of H. pylori suspension (density 10(9) colony forming units). Animals receiving indomethacin only or followed by administration of H. pylori suspension were sacrificed after 11 and 18 days. ROS activity was assessed by the level of lipid peroxidation (LPO) and the glutathione redox status by the ratio between oxidized and reduced glutathione (GSSG/GSH). Indomethacin did not significantly increase the level of LPO and the GSSG/GSH ratio. When H. pylori suspension was given together with indomethacin the LPO was increased both on days 11 and 18 and GSSG/GSH on day 18. H. pylori, thus, substantially increases glutathione redox ratio and lipid peroxidation in gastric mucosa, which may play an important role in the pathological mechanisms of this bacterium. The findings support the idea that dietary antioxidants could be beneficial in combination therapy for eradication of H. pylori.

Changes of activated macrophages and apoptotic cell count in the organs of rats during experimental sepsis.

OBJECTIVE: Leukocyte migration plays an important role in inflammation. The aim of our study was to detect the activated macrophage count and to define the apoptotic cell count in the rat's liver and lungs during different stages of sepsis and to clarify whether the activity of macrophages is associated with the apoptotic cell count in the course of the septic process. MATERIAL AND METHODS: Experimental sepsis was induced by inoculating Wistar rats intraperitoneally with E. coli cells. The liver and lung tissue was obtained 2, 6, 24, 48 and 120 hours after inoculation, and blood smears to detect the leukocyte volume were prepared at the same time. Macrophage activity was studied by immunohistochemical staining, using the ABC method. Apoptotic cell count was detected with the "In Situ Cell Death Detection Kit". RESULTS: Decrease in the total count of leukocyte and lymphocyte percentage and a rise in the percentage of neutrophils in the blood were evidences of a strong inflammation process in an organism. The count of activated macrophages in the liver was high, showing the maximum level at the end of the 2(nd) h after inoculation, after which it began to fall. Apoptotic cell count rose after a decrease in macrophage activity. In the lungs both changes - a decrease in activated macrophage level and a rise in the apoptotic cell count took place later on. CONCLUSION: Our investigations indicate that a decrease in the activated macrophage level is connected with an increased rise in the apoptotic cell count in both organs depending on the stage of the disease and occurs in the liver earlier than in the lungs but the process of cell apoptosis was more intensive in the lungs.