[Morphological and ultrastructural changes in the rat kidney after experimental sepsis]. / Morfologicheskie i ultrastrukturnye izmeneniia kletok v pochkakh krys posle éksperimental'nogo sepsisa.

UNLABELLED: Experimental sepsis was investigated in 42 male white Wistar rats. The animals were divided into 7 equal groups. Suspended E. coli cells (2 x 10(7) per 100 g body weight) were injected into the tail vein in groups I-VI, group VII served as a control group. The rats were sacrificed with cervical dislocation at different times after injection: in 45 min (group I), 2 h (group II), 6 h (group III), 24 h (group IV), 48 h (group V), and 120 h (group VI). Samples of kidneys were taken and embedded in paraffin and EPON-812 for histological and electron microscopical evaluation, respectively. RESULTS: histological examination demonstrated that changes in kindeys started in 2 h after infection to achieve the maximum level in 24 h, showing thereafter a tendency to decrease. A significant tissue damage was first seen in the loop and distal tubules of nephrons, and then expanded to the proximal tubules. Electron microscope examination demonstrated that changes in podocytes and cytopodia could be distinctly differentiated in 2 h after infection and obviously increased in the course of the experiment. The podocytes were enlarged, the processes were expanded and adhered to each other. For that reason the number of filtration pores in the glomerular basal membrane decreased. The count of mesangial cells in the glomerulus was increased.

Dissemination of bacteria in multiple organs associated with apoptosis and macrophage activity in different stages of experimental sepsis.

BACKGROUND: Gram negative sepsis is reported to induce massive translocation of bacteria into tissues, which associates with decreased macrophage function and increased macrophage apoptosis. AIMS: The objective of this study was to detect the translocation of bacteria into different organs and to evaluate macrophage activity and the apoptosis of macrophages in the liver during different stages of sepsis and to correlate these parameters. MATERIAL: Wistar rats (n = 43) were inoculated intraperitoneally with an E. coli and divided into 5 groups, which were killed at different times. METHODS: Counts of translocated bacteria in tissues were evaluated by using morphological and bacteriological methods. Macrophage activity and apoptotic cells in the liver were studied by applying immunohistochemical methods. RESULTS: The counts of E. coli were the highest in the organs and blood 6 h after the onset of sepsis, being in correlation with the highest counts of apoptotic cells in the liver and the falling counts of activated macrophages. The counts of microbes show a new wave of elevation in tissues by 120th h. CONCLUSIONS: The massive penetration of bacteria, the depressed macrophage response in early sepsis following the increased rate of apoptotic macrophages, the different rate of bacterial multiplication in tissues and blood and the second wave of the multiplication of bacteria in tissues in late sepsis all refer to the significance of developing immune dysfunction.

Microvascular permeability to the F(ab')2 fragment of IgG in the male rat reproductive tract at puberty.

Development of contraceptive vaccines has recently raised much interest following the cloning of the sperm and oocyte components involved in the sperm-oocyte interaction. The main difficulty of immunocontraception in the male is the poor access of antibodies to the luminal compartment. As recent literature suggests that many substances are transported to the testis by receptor-mediated or fluid-phase transcytosis, the dependence of the transport of IgG on the Fc receptor was studied in the present investigation by comparing the penetration of whole IgG and the F(ab')2 fragment of IgG to the testis and epididymis. The maximum volume of distribution (Veq) for the F(ab')2 fragment was significantly higher than that for whole IgG in the testis of 30-60-day old rats, in the caput and cauda of 30- and 45-day old rats and the corpus of 45-day old rats. The speeds at which equilibrium between tissue extracellular fluid and serum was reached (K) for the F(ab')2 fragment and whole IgG were significantly different in the testicular capsule of the 60-day old, in the caput and corpus of the 45- and 60-day old and in the cauda of the 45-day old rats. The microvascular permeabilities (PE) to the F(ab')2 fragment were more than 2-fold higher than those to whole IgG in the testis of the 20-, 45- and 60-day old, in the testicular capsule of the 20- and 45-day old, in the caput of 20-, 30- and 60-day old and in the corpus of 20-day old rats. The PE to whole IgG was more than 2-fold higher than that to the F(ab')2 fragment in the cauda of the 45-day-old rats. The PE to the F(ab')2 fragment increased steadily from 20 to 60 days of age in the testis and caput, but in the corpus there was a more abrupt increase between 30 and 45 days of age. In the cauda, PE remained in the same range of magnitude throughout pubertal development. These results suggest that the F(ab')2 fragment reaches the lumen of the reproductive tract more easily than whole IgG from 30 days of age onwards in the testis, whereas in the caput, corpus and cauda epididymidis the rate at which F(ab')2 fragment reaches the lumen increases only temporarily at the time of appearance of spermatozoa in the lumen. Transport of IgG to the male reproductive tract is thus unlikely to be mediated by Fc receptors.