Cortisone-treated Rats Research Articles

The Effect of Insulin-Like Growth Factor I on Healing of Colonic Anastomoses in Cortisone-Treated Rats

This study was designed to investigate whether intraperitoneally injected insulin-like growth factor I is able to protect colonic healing from the adverse effects of hydrocortisone therapy. Eighty female Wistar rats were randomized into four groups (20 rats each). After resection of a segment of transverse colon, an end-to-end anastomosis was performed. Hydrocortisone (5 mg/kg body weight) was injected intramuscularly in rats of cortisone (Group B) and insulin-like growth factor I + cortisone (Group D) groups once daily for seven days before and after the operation. Insulin-like growth factor I (2 mg/kg body weight) was intraperitoneally injected in rats of the insulin-like growth factor I (Group C) and the insulin-like growth factor I + Cortisone (Group D) groups immediately after operation and on the second, fourth, and sixth postoperative days. Rats were killed on the seventh postoperative day. Anastomoses were graded macroscopically and histologically, and bursting pressures and anastomotic hydroxyproline levels were recorded. Statistical analyses were performed by using Fisher's exact test for the comparison of proportions and ANOVA for the comparison of means among groups with subsequent post-hoc analysis using Bonferroni correction. Leakage rate was significantly higher in the cortisone (Group B) group. Bursting pressures were significantly lower in the cortisone group, whereas they were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups (Group C and D). Histology revealed a significant decrease of inflammatory cell infiltration, neoangiogenesis, and fibroblast activity in the cortisone group compared with the control group, whereas these parameters were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. Hydroxyproline levels were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. Hydrocortisone inhibits the healing of colonic anastomoses. However, insulin-like growth factor I given intraperitoneally mediates the deleterious effects of cortisone and protects colonic healing in rats.

Adrenalectomy abolishes antagonism of α‐adrenoceptor‐mediated hypotension by a β‐blocker in conscious rats

1. The effects of a single bolus injection of propranolol, atenolol or ICI 118,551, non-selective beta-, selective beta 1- and selective beta 2-adrenoceptor antagonists, respectively, on mean arterial pressure (MAP) and plasma catecholamine concentrations were examined in seven groups of conscious and unrestrained adrenalectomized rats receiving a continuous infusion of the alpha-adrenoceptor antagonist phentolamine. In all rats adrenaline was undetectable in the plasma four days after adrenalectomy. 2. In the first three groups, phentolamine significantly decreased MAP and increased the plasma concentrations of noradrenaline. The injection of propranolol, atenolol or ICI 118,551 in Groups I, II and III, respectively, caused a small increase in MAP and a small, but not significant, decrease in plasma noradrenaline concentrations. 3. Groups IV, V and VI were given a continuous infusion of adrenaline for 1 h prior to the infusion of phentolamine, followed by a bolus injection of propranolol, atenolol or ICI 118,551, respectively. Group VII was treated similarly to IV, but was also given daily cortisone replacement after adrenalectomy. Adrenaline slightly, but not significantly, decreased MAP while phentolamine significantly decreased MAP and increased plasma noradrenaline concentrations in all groups. A subsequent injection of a beta-blocker caused a significant increase in MAP in each group and a slight decrease in the plasma level of noradrenaline which reached statistical significance in group VII. The pressor effect of propranolol was significantly greater in the cortisone-treated rats (Group VII) than in Group IV. 5. The results suggest that adrenaline and adrenocortical steroids are both involved in the antagonism of alpha-adrenoceptor-induced hypotension by a beta-blocker.

Effect of cortisone on cells at the bone-marrow interface

A study of the association between the rate of proliferation of marrow fibroblast-like stromal cells (in vitro) and the rate of endosteal bone mineralization (EsMR) (in vivo) was undertaken in an osteopenic rat model. We report that 200 g male rats treated with cortisone acetate (5 mg/day for 7 days) exhibit decreases in marrow fibroblast colony-forming units (FCFU) and tetracycline-based measurements of EsMR at the level of the femoral midshaft. In cortisone-treated rats recovering for 1-3 weeks, the FCFU census and EsMR normalized during the first posttreatment week, remained at control levels after 2-3 weeks, and exhibited a relapse in the third week which signified only partial recovery. These changes were unrelated to patterns of body weight gain. The data indicate that the FCFU census can serve to index endosteal osteoblast vigor.

Diaphragm atrophy and weakness in cortisone-treated rats.

Despite frequent therapeutic use, the potential of corticosteroids to produce respiratory muscle myopathy is unknown. We studied effects of chronic steroid treatment on diaphragm mass and function. Eleven Sprague-Dawley rats were treated with cortisone acetate (100 mg.kg-1.day-1 im) for 10 days. Controls (injected with vehicle) included 11 freely eating rats and 11 animals pair fed to match food intake of cortisone rats. Steroid treatment depressed body weight 30% compared with controls. Mass of diaphragm, gastrocnemius, and extensor digitorum longus showed significant atrophy (30%); heart and soleus were unaffected. Isometric contractile properties of costal diaphragm strips were studied in vitro using direct stimulation. The force-frequency relationship was markedly depressed by steroid treatment, both at low and high frequencies. However, force developed per unit cross-sectional area was similar among all three groups, as were twitch characteristics. When stimulated every minute, forces developed by control strips fell progressively, whereas the forces of cortisone-treated strips remained unchanged. When stimulated every 5 s, the fall in force was not different between groups. We conclude that cortisone weakened the diaphragm by decreasing muscle mass but made the diaphragm more resistant to one form of fatigue in vitro.

Impaired clearance of aerosolized Legionella pneumophila in corticosteroid-treated rats: a model of Legionnaires' disease in the compromised host.

To develop a model of legionnaires' disease in a host with defective cell-mediated immunity, rats were treated with subcutaneous cortisone acetate and exposed to aerosolized Legionella pneumophila. Bacterial clearance, histopathology, cell recovery by bronchoalveolar lavage, serology, and splenocyte blastogenesis to heat-killed L. pneumophila were studied in cortisone-treated rats and normal controls. Corticosteroid administration resulted in a dosage-related defect in the clearance of L. pneumophila. Cortisone-treated animals had a diffuse, progressive pneumonitis, but the influx of neutrophils to the lung, the serum antibody response, and the sensitization of splenocytes to L. pneumophila were not impaired by corticosteroids. The marked lymphocyte depletion observed in cortisone-treated animals may have contributed to defective expression of cell-mediated immunity. This model may be useful in further studies of the pathogenesis and treatment of legionellosis in the compromised host.

Morphology, development and behavior of pneumocystis carinii observed by light-microscopy in nude mice

The present paper describes the morphology, development and behavior of Pneumocystis carinii, especially of the trophozoites in the alveoli of conventionally raised BALB/c nude mice, by using phase-contrast microscopy, paraffin sections and semiultrathin sections embedded in JB-4 plastic. Under phase-contrast microscopy, trophozoites were ameboid in external appearance and 2 to 8 micron in diameter. Usually they have one or more lucid spherical vacuoles and one less lucid nucleus in the cytoplasm. Maturation and independence of intracystic bodies were observed in the developing cysts. The intracystic bodies were polymorphic, i.e. spherical, ameboid or elongated. The paraffin sections using the double staining of P. carinii with Gomori's methenamine silver nitrate (GMS) and Giemsa, showed a small number of mature cysts containing intracystic bodies and a large number of trophozoites within the characteristic honeycombed material in the alveolar spaces. In order to investigate the morphology and parasitizing behavior of the trophozoites and cysts as well as the response of alveolar tissue in more detail, semiultrathin sections of 0.5-2 micron thickness were made from the materials embedded in JB-4 plastic and stained with Giemsa. In lightly infected alveoli, some trophozoites and cysts were found to be closely attached to the Type I alveolar epithelial cells. In heavily infected alveoli, almost all alveoli were filled with trophozoites, cysts, debris of the host cells, and occasionally phagocytic cells (macrophages and neutrophils) containing cysts or trophozoites were found. It was noted that the cysts were very few in number (1%) compared with the number of the trophozoites in nude mice in a 0.4 mm2 area of 2 micron thick lung sections. The host tissue of nude mice in this study was not as strongly affected by the organisms as that in cortisone-treated rats and P. carinii pneumonia patients. In the present study the morphology of P. carinii found in nude mice was not different from that found in rats and in man.

Three-day continuous drainage of pancreatic juice in the cortisone-treated conscious rat: analysis of enzyme activities and ultrastructural changes.

We have investigated the short-term effects of hydrocortisone (60 mg/kg per day) and placebo on basal and stimulated pancreatic secretion in the conscious rat. Volume and enzyme secretion were determined; fine structural changes were examined simultaneously. The pancreatic and bile ducts were cannulated separately; pancreatic juice was drained via an isolated fistula, and bile was recirculated into the duodenum. The application of hydrocortisone led to an almost complete inhibition of the secretory response of the exocrine pancreas when stimulated with 0.25 U secretin in combination with 5 X 10(-8) g caerulein per h. It strongly affected the secretion rates of volume, protein, lipase, chymotrypsin, trypsin and carboxypeptidase, whereas the secretion rate of alpha-amylase continued to show a slight increase after stimulation. After stimulation with secretin and caerulein, the hydrocortisone-treated animals showed a higher density of zymogen granules in the acinar cell and an increase in the number of autophagic vacuoles in comparison to the equally stimulated placebo-treated rats. It is concluded that the short-term inhibition of pancreatic secretion by hydrocortisone occurs largely as a result of an inhibition of cellular enzyme discharge.

Increase in pulsatile secretion of growth hormone during failure of catch-up growth following glucocorticoid-induced growth inhibition.

The pattern of growth hormone (GH) secretion was determined in rats injected with cortisone acetate, 5 mg/rat/day subcutaneously, or with an equivalent volume of saline for 4 days from age 40 days. Cortisone injections resulted in inhibition of growth of body weight and tail length. During recovery the rats resumed a normal rate of growth but failed to show catch-up growth acceleration. From 17 to 27 days of recovery, plasma was sampled at 15-min intervals through the lights-on period, 06:00 to 18:00, via a catheter chronically implanted in the superior vena cava. During sampling each rat was housed singly in an insulated chamber, unrestrained, and with food and water ad lib. Cortisone-treated animals had a normal periodicity of GH plasma concentration, but they showed a reduction in values in the range of 50 to 99 ng/ml (P less than 0.01) and an increase of values in the range of 200 to 499 ng/ml (P less than 0.025) and above 1000 ng/ml (P less than 0.05). The area under the GH concentration curve of the cortisone-treated rats was significantly greater than that of the controls, 100.9 +/- 18.7 (mean +/- SE) units vs 55.3 +/- 7.4 (P less than 0.025). Thus, increased growth hormone secretion during the light phase persisted in spite of failure of catch-up growth acceleration. The findings indicate that the mechanism involved in GH release is linked to the catch-up growth control.

Immune suppression and histophysiology of the immune response. I. Cortisone acetate and lymphoid cell migration.

Seven daily intramuscular (im) injections of cortisone acetate (25 mg/Kg b.w.) given to rats or rabbits produced, (i) a pronounced reduction in the numbers of small lymphocytes in thymus-independent areas, (ii) atrophy of the thymic cortex, (iii) atrophy of germinal centres and (iv) a consequent depressed production of germinal centre-derived cells. Lymphocyte depletion was not caused by cell lysis. Moreover cell traffic between peripheral lymphoid organs did not seem to be altered. A revival of the depressed germinal centres in cortisone-treated (inbred) rats could be achieved by a transfer of bone-marrow cell suspensions from normal, cortisone-treated or T-cell-deprived animals. It was concluded that cortisone acetate arrests the migration of B-lymphocytes from the bone marrow to germinal centres in peripheral lymphoid organs, and that the accumulations of lymphoid cells in the bone marrow of cortison-treated animals might be composed of immature or mature T- and B-lymphocytes.

Folic acid absorption in the proximal jejunum of streptozotocin-diabetic and cortisone-treated rats

Folic acid absorption in the proximal jejunum of streptozotocin-diabetic and cortisone-treated rats

5?-AMP hydrolysis by suspensions and homogenates of pancreatic islet cells from normal and cortisone-treated rats

Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split Pi from 5'-AMP at a rate of 87 nmol/h per microgram DNA, and from beta-glycerophosphate at a rate of 25 nmol/h per microgram DNA. Km for 5'-AMP was about 54 microM. Adenosine or theophylline inhibited the 5'-AMP hydrolysis. Homogenization of the cells increased the activity toward 5'-AMP by 23% and that toward beta-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5'-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5'-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5'-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5'-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5'-AMP in cortisone-treated rats.

Effects of a Protein Deprived Diet on the Hepatotoxicity, and the DNA Synthetic, Mitogenic, and Immunological Actions of Microbial Lipopolysaccharides in the Rat

Rats fed an 18% casein (Cs) or a protein deprived diet (PD) for 8 weeks received injections of Escherichia coli lipopolysaccharides (LPS) in both hind foot pads. While these injections were tolerated in Cs rats, about 50% of PD rats died after 1 or 2 days as a result of a massive necrosis of the liver. To a large extent these lesions were prevented by cortisone. Three days after injection of LPS, Cs rats exhibited a hypertrophy of the popliteal lymph nodes (PLN) and spleen, as well as a drastic increase in DNA synthesis in DNA synthesis in the PLN. Mitotic indices did not increase. The DNA synthetic responses to PLN in the surviving PD rats were much lower than in Cs animals, but a sharp rise in DNA synthesis and mitotic activity occurred in the spleen. The comparison with the effects of LPS in cortisone-treated rats showed that both cortisone-sensitive and -resistant cells participated in PLN activation in rats fed both diets, but that only cortisone-resistant lymphocytes entered mitosis in the spleens of PD rats. LPS also provoked a sharp drop in both DNA synthesis and mitosis in the thymus, probably due to a stress effect, since only cortisone-sensitive thymocytes were involved. In a second experimental series, immunological tests (Rosette-forming cells, Plaque-forming cells, serum hemagglutinin titers) were performed 7 days after intraperitoneal injection of LPS. The responses were not significantly different in Cs and PD rats. This is in contrast with the protein deficiency-induced depression of thymus-dependent humoral immunity.

Comparative Immunological Analysis of Host Plasma Proteins Bound to Bloodstream Forms of Trypanosoma brucei Subspecies

The presence, location, host specificity, identity, and quantity of rat plasma proteins bound to bloodstream forms of Trypanosoma brucei subsp. brucei, T. brucei subsp. rhodesiense, and T. brucei subsp. gambiense were determined by a quantitative indirect fluorescent-antibody method and gel immunoassays. Fluorescence differences between trypanosomes obtained from rats and mice and treated with antiserum to normal rat plasma indicated that most, if not all, of the bound plasma proteins were host specific. Removal of plasma proteins by trypsinization of parasites provided evidence for their attachment to the surface of the parasite. The accreted proteins were found to be host albumin, immunoglobulin G (IgG), and complement (C3). The same quantities of these three plasma proteins were present on T. brucei subspecies collected from normal rats at 2 days postinfection, during low or peak parasitemias, or from cortisone-treated rats. IgM could only be detected on parasites collected from normal rats at peak parasitemia. With the aid of rocket immunoelectrophoresis, host albumin and IgG were found to account for 0.2 and 0.05%, respectively, of the total soluble proteins of the bloodstream forms. It was concluded from this study that: (i) host plasma proteins were bound to parasites early in the infection, suggesting a mechanism of adaptation to the mammalian host; (ii) the surface-bound IgG was not the result of a specific immune response against the parasites but might be the cause of C3 attachment; (iii) among the bloodstream forms of the three T. brucei subspecies, there were no differences in amounts of surface-bound albumin, IgG, or C3. A comparison between the present data dealing with T. brucei subspecies, on the one hand, and the previously published results concerning T. congolense, on the other, revealed significant differences in the amounts of the host plasma proteins attached to these hemoflagellates.

The Effect of a Magnesium Deficient Diet and Cortisone on the Growth of the Rat Incisor

Incisors of Mg-deficient rats showed a marked inhibition of eruption and a decrease in mitoses of apical tissues. Cortisone administration resulted in some increase in eruption rate and cell division though these remained below the values of Mg-supplemented controls. An improvement in gross condition and a less severe histopathology of incisor tissues were also observed in cortisone-treated rats.

Studies of poly(A+-RNA in mouse hepatoma and cortisone-stimulated rat liver

The content of poly(A)-containing RNA in subcellar fractions has been investigated both in cortisone-treated rat liver and experimental hepatoma cells. The fractions included nuclei, cytoplasm, mitochondria, free and membrane-bound polyribosomes. 1) In both cases of genome activation (cortisone induction and hepatoma cells) an increase in poly(A) content of all subcellular fractions except free polyribosomes was observed. 2) Cortisone was found to induce elongation of poly(A) segments detected in both nuclei and cytoplasm. 3) An increase in the poly(A) block size also was found to be stimulated in nuclei and cytoplasm of hepatoma cells. 4) The observed elongation in poly(A) length occurred against the background of an increase of the population of of poly(A)-RNA's.

Chromosomes of lymph node metastases derived from Ehrlich ascites carcinoma cells inoculated into rats.

The inoculation of Ehrlich ascites carcinoma cells in irradiated and cortisone-treated rats induced an ascitic tumor and lymph node metastases. Chromosome banding analysis showed that metastatic lymph nodes are composed of Ehrlich tumor cells and normal rat metaphases, derived from reactive host cells.

Cartilage Sulfation and Serum Somatomedin in Rats During and After Cortisone-Induced Growth Arrest

The uptake of sulfate by rib cartilage in vitro and in vivo and the serum somatomedin activity by bioassay were determined in male rats during and after cortisone-induced growth arrest. Experimental treatment consisted of subcutaneous injections of cortisone acetate in a dose of 2.5 mg/rat/day for 4 days, beginning at 29 to 30 days of age in Buffalo rats, or 5 mg/rat/day for 4 or 5 days, beginning at 39 to 41 days of age in Long-Evans rats. Groups of hypophysectomized rats were studied in parallel in one experiment. The sulfate uptake in the controls declined linearly with increasing age in both the in vitro and the in vivo studies. Hypophysectomy resulted in a constant low level of sulfate uptake in vitro. At the end of cortisone treatment, the in vitro sulfate uptake was approximately midway between that of the hypophysectomized rats and that of controls; at 7 days recovery, it was at the control level; at 14 days it showed an additional rise above the control value; from 14 days to 35 days it declined parallel with but above the sulfate uptake of controls. The in vivo sulfate uptake was depressed by cortisone treatment. During recovery it approximately control values at recovery day 21. In succeeding recovery periods in vivo sulfate uptake remained at control levels. Serum somatomedin activity was significantly reduced during cortisone treatment; it returned to the control level by 21 days of recovery. The incubation of the cartilage of controls and cortisone-treated rats at 14 days of recovery with and without the presence of normal rat serum, cortisone recovery serum, or hypophysectomy serum resulted in significantly higher sulfate uptake in the cortisone-treated rat cartilage in each medium. These sera did not differ significantly in their stimulation of sulfate uptake in either cortisone recovery cartilage or control cartilage. Both treated and control cartilage had greater sulfate uptake with larger doses of serum added to the medium. The dose-response curves were parallel during treatment and early recovery; but the slopes of the dose-response curves of the cartilage of cortisone-treated rats were greater than those of the controls during late recovery. It is concluded that the increased in vitro sulfation after 14 days of recovery in cortisone-treated rats signifies a persistent alteration in cartilage metabolism. Normal in vivo sulfate uptake during that time may be the result of humoral controls. A mechanism other than the impairment of somatomedin production is probably involved in the failure of catch-up growth after glucocorticoid treatment in the rat.

Effect of Cortisone on Collagenolytic Activity in the Rat

The action of cortisone on bone collagen and collagenolytic activity has been investigated. Rats were injected subcutaneously with cortisone acetate and the collagen content, the incorporation of 14C-proline into 14C-hydroxy-proline, and the collagenolytic activity of the control and cortisone-treated rat bones were determined. The effect of cortisone on bone collagenolytic enzyme was also assayed.It was observed that cortisone administration caused a reduction of the collagen content and a decreased incorporation of 14C-proline into 14C-hydroxyproline. The collagenolytic activity of the bone was reduced and cortisone has also an inhibitory effect on bone collagenolytic enzyme. These results suggest that cortisone not only inhibits the biosynthesis of bone collagen but diminishes the collagenolytic activity of rat bone.Cortisone and bone collagenolytic activity. Cortisone is known to affect the metabolism of several constituents of connective tissue (1, 2) and it has been repotred that the re-sorption of ...

Comparison of mineralization of the tibial epiphyseal plate in immature rats following treatment with cortisone, propylthiouracil or after fasting.

Comparison of mineralization in the hypertrophic zone of the tibial epiphyseal plate in immature rats was carried out after treatment with cortisone, propylthiouracil, or after fasting. Under normal conditions, in the extracellular matrix at the calcification front, calcium and phosphate increased, sulfated mucopolysaccharides decreased, and matrix vesicles, which serve as the locus for the formation of hydroxyapatite crystals, increased. In propylthiouracil-treated rats, hydroxyapatite crystals were prominent, related to an increase in calcium deposition, a decrease of mitochondrial granules (thought to contain calcium and phosphate), an increase in the number of matrix vesicles, and to a marked decrease in the amount of sulfated mucopolysaccharide. In cortisone-treated rats, hydroxyapatite crystals were present but they were not as numerous as in the propylthiouracil-treated rats. Correspondingly, calcium deposition was slightly reduced, mitochondrial granules were more numerous than in the previous groups of rats, matrix vesicles were less numerous, and sulfated mucopolysaccharide were more prominent than in the propylthiouracil-treated rats. In fasted rats, hydroxyapatite crystals were markedly reduced or absent, and related to a decrease in calcium deposition, an increase in the number of mitochondrial granules (suggesting a delay in transport to the extracellular matrix). Matrix vesicles were markedly reduced in number, and sulfated mucopolysaccharide much more prominent than in either the cortisone or the propylthiouracil-treated rats.

Studies on the localization and the distribution of glucose-6-phosphatase in the liver cells of rats with several kinds of treatment

The localization and the distribution of G-6-Pase activity in the liver cells of rats which received several kinds of treatment such as alloxan, cortisone, anabolic steroid or CCI4 were observed biochemically and by electron microscopic cytochemical technique. G-6-Pase activity in the liver cell of normal untreated rats was concentrated in R-ER, S-ER and inside of nuclear envelope. Increase in G-6-Pase activity as shown by deposit was especially pronounced on the increased S-ER at a stage of marked rise of blood sugar in the alloxan diabetic rats, while increase in size and number of the deposits was observed on the increased R-ER at a stage of normal level of blood sugar in the cortisone-treated rats. Based on such result, increase in G-6-Pase activity of the liver cell treated with alloxan was different from that treated with cortisone in distribution and localization. These findings suggest that G-6-Pase may be synthesized in R-ER and it may be related to carbohydrate metabolism in S-ER. In the liver cells of the rats treated with anabolic steroid, G-6-Pase was found in the increased R-ER and the deposit was increased in cristae mitochondriales 24 hours after treatment. Presence of mitochondrial G-6-Pase in agreement with the cristae might indicate that they are not the result of diffusion from microsome. However, metabolic significance of mitochondrial G-6-Pase remains entirely unknown. In the liver cell injured by CCI4, G-6-Pase activity was loccalized on the S-ER which increased locally with reticular formation. This phenomenon seems favorable to maintaining the metabolism in the injured hepatocyte.