Effect of bullfrog (Rana catesbeiana) oil administered by gavage on the fatty acid composition and oxidative stress of mouse liver

The aim of the present study was to investigate the effects of daily intragastric administration of bullfrog oil (oleic, linoleic and palmitoleic acid-rich oil), corresponding to 0.4 percent of body weight for four weeks, on fatty acid composition and oxidative stress (lipid peroxidation and catalase activity) in mouse liver. The activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT), biomarkers of tissue injury, were determined in liver homogenates and serum. The proportions of 18:2n-6, 20:4n-6, 20:5n-3, and 22:6n-3 (polyunsaturated fatty acids, from 37 to 60 percent) in the total fatty acid content were increased in the liver of the bullfrog oil-treated group (P < 0.05) compared to control. At the same time, a significant decrease in the relative abundance of 14:0, 16:0, and 18:0 (saturated fatty acids, from 49 to 25 percent) was observed. The hepatic content of thiobarbituric acid reactive substances (TBARS) was increased from 2.3 ± 0.2 to 12.3 ± 0.3 nmol TBA-MDA/mg protein and catalase activity was increased from 840 ± 32 to 1110 ± 45 æmol reduced H2O2 min-1 mg protein-1 in the treated group. Bullfrog oil administration increased AST and ALP activities in the liver (from 234.10 ± 0.12 to 342.84 ± 0.13 and 9.38 ± 0.60 to 20.06 ± 0.27 U/g, respectively) and in serum (from 95.41 ± 6.13 to 120.32 ± 3.15 and 234.75 ± 11.5 to 254.41 ± 2.73 U/l, respectively), suggesting that this treatment induced tissue damage. ALT activity was increased from 287.28 ± 0.29 to 315.98 ± 0.34 U/g in the liver but remained unchanged in serum, whereas the GGT activity was not affected by bullfrog oil treatment. Therefore, despite the interesting modulation of fatty acids by bullfrog oil, a possible therapeutic use requires care since some adverse effects were observed in liver.

Effect of bullfrog (Rana catesbeiana) oil administered by gavage on the fatty acid composition and oxidative stress of mouse liver.

The aim of the present study was to investigate the effects of daily intragastric administration of bullfrog oil (oleic, linoleic and palmitoleic acid-rich oil), corresponding to 0.4% of body weight for four weeks, on fatty acid composition and oxidative stress (lipid peroxidation and catalase activity) in mouse liver. The activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT), biomarkers of tissue injury, were determined in liver homogenates and serum. The proportions of 18:2n-6, 20:4n-6, 20:5n-3, and 22:6n-3 (polyunsaturated fatty acids, from 37 to 60%) in the total fatty acid content were increased in the liver of the bullfrog oil-treated group (P < 0.05) compared to control. At the same time, a significant decrease in the relative abundance of 14:0, 16:0, and 18:0 (saturated fatty acids, from 49 to 25%) was observed. The hepatic content of thiobarbituric acid reactive substances (TBARS) was increased from 2.3 +/- 0.2 to 12.3 +/- 0.3 nmol TBA-MDA/mg protein and catalase activity was increased from 840 +/- 32 to 1110 +/- 45 micromol reduced H2O2 min-1 mg protein-1 in the treated group. Bullfrog oil administration increased AST and ALP activities in the liver (from 234.10 +/- 0.12 to 342.84 +/- 0.13 and 9.38 +/- 0.60 to 20.06 +/- 0.27 U/g, respectively) and in serum (from 95.41 +/- 6.13 to 120.32 +/- 3.15 and 234.75 +/- 11.5 to 254.41 +/- 2.73 U/l, respectively), suggesting that this treatment induced tissue damage. ALT activity was increased from 287.28 +/- 0.29 to 315.98 +/- 0.34 U/g in the liver but remained unchanged in serum, whereas the GGT activity was not affected by bullfrog oil treatment. Therefore, despite the interesting modulation of fatty acids by bullfrog oil, a possible therapeutic use requires care since some adverse effects were observed in liver.

Changes of fatty acid composition in incubated rat pancreatic islets.

OBJECTIVE: The hypothesis that changes in fatty acId composition of pancreatic islets occur during incubation was investigated. METHODS: The content and composition of fatty acIds (FA) from rat pancreatic islets and culture medium after incubation for 1 and 3 hours in the absence or in the presence of 5.6, 8.3, or 16.7 mM glucose were determined by HPLC analysis. RESULTS: The FA content of pancreatic islets was reduced after 1 hour incubation in the absence of glucose. However, the total FA content was restored by incubating in the presence of 5.6 mM glucose and exceeded by incubating in the presence of 8.3 mM or 16.7 mM glucose. Saturated FA contributed a substantially greater proportion of the total FA increase in comparison to unsaturated FA, being palmitic and stearic acIds the most important. The total lipId content of pancreatic islets was not increased if the period of incubation in the presence of glucose was extended to 3 hours. A substantial amount of FA was found in the medium after 1 hour incubation in the absence of glucose: 141 ng per 80 islets for saturated and 75 ng per 80 islets for unsaturated. The release of FA from islets is increased in the presence of glucose. CONCLUSION: The release of FA from islets is a novel finding and may be related to modulation of B-cell function.

Evidence that arachidonic acid derived from neutrophils and prostaglandin E2 are associated with the induction of acute lung inflammation by lipopolysaccharide of Escherichia coli.

OBJECTIVE: The involvement of arachidonic acid (AA) and PGE2 during the E. coli lipopolysaccharide (LPS)-induced acute lung injury was investigated. MATERIAL: Adult male Wistar rats were used. For in vitro studies, rat neutrophils, bronchoalveolar lavage (BAL) fluid, and lug vascular endothelium were used, as described below. TREATMENT: Rats were given an intratracheal injection of LPS (750 microg). METHODS: Total and differential cell counts in BAL fluid; enzyme-linked immunoassay (ELISA) analyses of TNF-alpha, IL-1beta, LTB4 and PGE2 in BAL, and immunohistochemical detection of ICAM-1 on lung vascular endothelium were performed six h after LPS challenge. Fatty acid composition of blood neutrophils and plasma was analyzed by HPLC. RESULTS: Rats instilled with LPS presented a sixty three-fold increase in the number of neutrophils in BAL (from 0.5 x 10(6) to 31.5 x 10(6) cells), accompanied by increased levels of TNF-alpha and IL-1beta (p < 0.001), and a three-fold increase in ICAM-1 expression on vascular endothelium. The content of AA in blood neutrophils was reduced by 50%, whereas the level of PGE2 in BAL was increased by 3.5 fold, without changes in the levels of LTB4. CONCLUSIONS: These findings suggest that AA and PGE2 are associated with LPS challenge.

Cholesterol changes the fatty acid composition of rat enterocytes.

The effect of free cholesterol on the fatty acid composition and growth of rat fetal enterocytes was investigated in the absence and presence of 10% (v/v) fetal calf serum. Cholesterol caused a significant reduction of cell number after 6 and 12 h in culture. The fatty acid composition of enterocytes cultured in the presence of serum was also changed by the presence of 20 microM cholesterol. The fatty acid profile was determined by HPLC using fluorescence detection (325 nm excitation and 395 nm emission). Cholesterol (20 microM) increased the proportion (given in percentage of the total fatty acids) of the following fatty acids in cultured cells: lauric (by 42%), oleic (by 34%), linoleic (by 44%) and gamma-linolenic (by 20%) acids and reduced the proportion of palmitic (by 12%), stearic (by 20%), arachidonic (by 21%) and docosahexaenoic (by 44%) acids. In addition to modifying the content of individual fatty acids, cholesterol increased the polyunsaturated/saturated fatty acid ratio from 0.48 to 0.67 and the unsaturation index from 67.12 to 75.30. This is the first evidence that cholesterol modifies fatty acid composition possibly via de novo fatty acid synthesis and desaturation.

Cholesterol changes the fatty acid composition of rat enterocytes

The effect of free cholesterol on the fatty acid composition and growth of rat fetal enterocytes was investigated in the absence and presence of 10 percent (v/v) fetal calf serum. Cholesterol caused a significant reduction of cell number after 6 and 12 h in culture. The fatty acid composition of enterocytes cultured in the presence of serum was also changed by the presence of 20 æM cholesterol. The fatty acid profile was determined by HPLC using fluorescence detection (325 nm excitation and 395 nm emission). Cholesterol (20 æM) increased the proportion (given in percentage of the total fatty acids) of the following fatty acids in cultured cells: lauric (by 42 percent), oleic (by 34 percent), linoleic (by 44 percent) and gamma-linolenic (by 20 percent) acids and reduced the proportion of palmitic (by 12 percent), stearic (by 20 percent), arachidonic (by 21 percent) and docosahexaenoic (by 44 percent) acids. In addition to modifying the content of individual fatty acids, cholesterol increased the polyunsaturated/saturated fatty acid ratio from 0.48 to 0.67 and the unsaturation index from 67.12 to 75.30. This is the first evidence that cholesterol modifies fatty acid composition possibly via de novo fatty acid synthesis and desaturation

Comparative effects of fish oil given by gavage and fish oil-enriched diet on leukocytes.

The comparative effects of fish oil given by gavage and fish oil enriched diet on metabolism and function of lymphocytes and macrophages were investigated. For this purpose, the following parameters were examined: 1) phagocytosis capacity, production of superoxide (O2*-) and hydrogen peroxide (H2O2) by macrophages, 2) lymphocytes proliferation capacity, 3) antioxidant enzyme activities in the mesenteric lymph nodes (MEN) and liver, 4) Thiobarbituric Acid Reactive Substances (TBARS) content in MLN, liver, and plasma, 5) total antioxidant capacity of the plasma, and 6) fatty acid composition of macrophages, MLN, liver and plasma. Both FO treatments did not affect phagocytosis capacity but increased hydrogen peroxide production by macrophages in the presence of PMA. FO given by gavage markedly increased lymphocytes proliferation both in the absence (5.8-fold) and in the presence (16.7-fold) of Con A, whereas FO-rich diet showed an increase in the presence of Con A only (53.3%). FO given by gavage raised the proliferation index by 2.9-fold and FO-rich diet increased by 29% only as compared to controls. Concomitantly, FO given by gavage was more effective to increase TBARS content in plasma. The proportion of some fatty acids in the tissues and cells was also differently changed depending on the way FO was administered to rats: in particular: myristic, arachidonic, and eicosapentaenoic acids. This fact may partially explain the differences between both FO treatments.

Regulation of antioxidant enzyme activities in male and female rat macrophages by sex steroids

Human and animal immune functions present sex dimorphism that seems to be mainly regulated by sex hormones. In the present study, the activities of the antioxidant enzymes total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were measured in intraperitoneal resident macrophages from adult male and female rats. In addition to comparing males and females, we also examined the regulation of these enzyme activities in macrophages by sex steroids. GSH-Px activity did not differ between male and female macrophages. However, both total SOD and CAT activities were markedly higher in females than in males (83 and 180 percent). Removal of the gonads in both males and females (comparison between castrated groups) increased the difference in SOD activity from 83 to 138 percent and reduced the difference in CAT activity from 180 to 86 percent. Castration and testosterone administration did not significantly modify the activities of the antioxidant enzymes in male macrophages. Ovariectomy did not affect SOD or GSH-Px activity but markedly reduced (48 percent) CAT activity. This latter change was fully reversed by estrogen administration, whereas progesterone had a smaller effect. These results led us to conclude that differences in the SOD and CAT activities may partially explain some of the differences in immune function reported for males and females. Also, estrogen is a potent regulator of CAT in macrophages and therefore this enzyme activity in macrophages may vary considerably during the menstrual cycle

Regulation of antioxidant enzyme activities in male and female rat macrophages by sex steroids.

Human and animal immune functions present sex dimorphism that seems to be mainly regulated by sex hormones. In the present study, the activities of the antioxidant enzymes total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were measured in intraperitoneal resident macrophages from adult male and female rats. In addition to comparing males and females, we also examined the regulation of these enzyme activities in macrophages by sex steroids. GSH-Px activity did not differ between male and female macrophages. However, both total SOD and CAT activities were markedly higher in females than in males (83 and 180%). Removal of the gonads in both males and females (comparison between castrated groups) increased the difference in SOD activity from 83 to 138% and reduced the difference in CAT activity from 180 to 86%. Castration and testosterone administration did not significantly modify the activities of the antioxidant enzymes in male macrophages. Ovariectomy did not affect SOD or GSH-Px activity but markedly reduced (48%) CAT activity. This latter change was fully reversed by estrogen administration, whereas progesterone had a smaller effect. These results led us to conclude that differences in the SOD and CAT activities may partially explain some of the differences in immune function reported for males and females. Also, estrogen is a potent regulator of CAT in macrophages and therefore this enzyme activity in macrophages may vary considerably during the menstrual cycle.

Walker-256 tumor growth causes oxidative stress in rat brain.

The elevated rate of oxygen consumption and high amount of polyunsaturated fatty acids make the central nervous system vulnerable to oxidative stress. The effect of Walker-256 tumor growth on oxi-reduction indexes in the hypothalamus (HT), cortex (CT), hippocampus (HC) and cerebellum (CB) of male Wistar rats was investigated. The presence of the tumor caused an increase in thiobarbituric acid reactant substances (TBARs) in the HT, CB and HC. Due to tumor growth, the activity of glucose-6-phosphate dehydrogenase increased in the HT and CB, whereas citrate synthase activity was reduced in the HT, CT and CB. Therefore, the potential for generation of reducing power is increased in the cytosol and decreased in the mitochondria of various brain regions of Walker-256 tumor-bearing rats. These changes occurred concomitantly with an unbalance in the brain enzymatic antioxidant system. The tumor decreased the activities of catalase in the HT and CB and of glutathione peroxidase in the HT, CB and HC, and raised the CuZn-superoxide dismutase activity in the HT, CB and HC. These combined findings indicate that Walker-256 tumor growth causes oxidative stress in the brain.

Effect of fatty acids on leukocyte function

Fatty acids have various effects on immune and inflammatory responses, acting as intracellular and intercellular mediators. Polyunsaturated fatty acids (PUFAs) of the omega-3 family have overall suppressive effects, inhibiting lymphocyte proliferation, antibody and cytokine production, adhesion molecule expression, natural killer cell activity and triggering cell death. The omega-6 PUFAs have both inhibitory and stimulatory effects. The most studied of these is arachidonic acid that can be oxidized to eicosanoids, such as prostaglandins, leukotrienes and thromboxanes, all of which are potent mediators of inflammation. Nevertheless, it has been found that many of the effects of PUFA on immune and inflammatory responses are not dependent on eicosanoid generation. Fatty acids have also been found to modulate phagocytosis, reactive oxygen species production, cytokine production and leukocyte migration, also interfering with antigen presentation by macrophages. The importance of fatty acids in immune function has been corroborated by many clinical trials in which patients show improvement when submitted to fatty acid supplementation. Several mechanisms have been proposed to explain fatty acid modulation of immune response, such as changes in membrane fluidity and signal transduction pathways, regulation of gene transcription, protein acylation, and calcium release. In this review, evidence is presented to support the proposition that changes in cell metabolism also play an important role in the effect of fatty acids on leukocyte functioning, as fatty acids regulate glucose and glutamine metabolism and mitochondrial depolarization

Effect of fatty acids on leukocyte function.

Fatty acids have various effects on immune and inflammatory responses, acting as intracellular and intercellular mediators. Polyunsaturated fatty acids (PUFAs) of the omega-3 family have overall suppressive effects, inhibiting lymphocyte proliferation, antibody and cytokine production, adhesion molecule expression, natural killer cell activity and triggering cell death. The omega-6 PUFAs have both inhibitory and stimulatory effects. The most studied of these is arachidonic acid that can be oxidized to eicosanoids, such as prostaglandins, leukotrienes and thromboxanes, all of which are potent mediators of inflammation. Nevertheless, it has been found that many of the effects of PUFA on immune and inflammatory responses are not dependent on eicosanoid generation. Fatty acids have also been found to modulate phagocytosis, reactive oxygen species production, cytokine production and leukocyte migration, also interfering with antigen presentation by macrophages. The importance of fatty acids in immune function has been corroborated by many clinical trials in which patients show improvement when submitted to fatty acid supplementation. Several mechanisms have been proposed to explain fatty acid modulation of immune response, such as changes in membrane fluidity and signal transduction pathways, regulation of gene transcription, protein acylation, and calcium release. In this review, evidence is presented to support the proposition that changes in cell metabolism also play an important role in the effect of fatty acids on leukocyte functioning, as fatty acids regulate glucose and glutamine metabolism and mitochondrial depolarization.

Modulation of hypersensitivity reaction by lipids given orally.

The effect of lipids administration by gavage (0.4% body weight) given daily during four weeks on the hypersensitivity reaction in trachea, upper and lower bronchi, liver, kidney, mesentery, and pancreas was investigated in male rats. The plasma exudation was assessed by using Evans blue (EB) dye extravasation method. There was a significant difference in the permeability of the organs in nonimmunized rats. The immunization increased the vascular permeability and the response with the organs varied greatly. The effect of lipids on anaphylactic reaction was compared to those of untreated rats (control group). The EB extravasation was significantly increased in the trachea obtained from rats treated with cocoa butter and soybean oil. In the upper bronchi of rats treated with soybean oil, the EB extravasation was increased. However, in the lower bronchi, none of the treatments with lipids changed the extravasation of EB. The same was observed in the liver and kidney. The animals treated with lipids by gavage did not present differences in EB extravasation in the mesentery. However, in the pancreas and duodenum, the treatment with fish and soybean oils and cocoa butter markedly lowered EB extravasation.

Effect of indole acetic acid on oxygen metabolism in cultured rat neutrophil.

1. Indole acetic acid (IAA) stimulates O2.- and H2O2 production in cells with peroxidase activity, such as neutrophils. The effect of pharmacological IAA concentration on oxygen metabolism and neutrophil functioning and viability in culture was investigated. 2. The results led to the conclusion that: (1) IAA causes death and marked ultrastructural changes in cultured neutrophils but does not affect lymphocytes; (2) these effects are not due to a reduction in the enzymatic antioxidant capacity of the cell, as indicated by catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px); (3) these effects are mainly due to an increase in the production of O2.- and H2O2, as suggested by the protective effect exhibited by the addition of CAT and SOD to cultured neutrophils, and (4) other reactive species (possibly peroxyl radicals) might play a role in the IAA effect on cultivated neutrophil viability.

Glutathione metabolism and glutathione S-conjugate export ATPase (MRP1/GS-X pump) activity in cancer. II. Cell-to-cell variability, relation with cellular activation state and functional absence of GS-X pump in lymphocytes.

A severe complication in late-stage cancer patients is host immunosuppression. It is suggested that overproduction of the highly cytostatic and cytotoxic antiproliferative cyclopentenone prostaglandins (CP-PGs) within the plasma of cancer-bearing subjects may contribute to immunosuppression. Lymphoid tissues of Walker 256 tumor-bearing rats accumulate large amounts of CP-PGs while the tumor tissue itself does not. Moreover, tumor cells may present differential sensitivity to CP-PGs due to the expression of the multidrug resistance-associated protein (MRP1) gene product which shows a Mg(2+)-dependent vanadate-sensitive glutathione S-conjugate export ATPase (GS-X pump) activity that extrudes CP-PGs from cells as glutathione S-conjugates. In this study, the possibility that deficient GS-X pump activity in immune cells that may be involved in the accumulation of CP-PGs is investigated. Rat lymph node lymphocytes do not exhibit any notable activity even when mitogen-stimulated. Conversely, although rat peritoneal resident (quiescent) or thioglycollate-stimulated (inflammatory) macrophages exhibit low GS-X pump activity, Bacillus Calmette-Guérin (BCG)-activated macrophages show a notable rise in the activity of the ATPase, suggesting that the cellular activation state may modulate GS-X pump activity/expression and that, under appropriate stimuli (e.g., during immune response) macrophages may provide a self-defense against electrophilic CP-PGs by forming GS-conjugates that can be extruded from cells through the GS-X pump. ras oncogene expression may be linked with MRP1/GS-X pump expression/activity, since C2C12 promyoblasts transformed by v-H-ras transfection doubled GS-X pump activity. These results support the proposition that the accumulation of CP-PGs and the immunosuppression of tumor-bearing subjects may be attributed to a lack of GS-X pump activity/expression in lymphocytes.

Effects of the antiproliferative cyclopentenone prostaglandin A1 on glutathione metabolism in human cancer cells in culture.

Homeostatic mechanisms for the maintenance of glutathione (GSH) are fundamental in the provision of a cellular defense against electrophilic/oxidant challenges. Cyclopentenone prostaglandins (CP-PGs) are powerful antiproliferative endogenous substances that may act as electrophilic regulating compounds, by virtue of the presence of an alpha,beta-unsaturated carbonyl group in the cyclopentane ring. Nevertheless, differential resistance to CP-PG cytotoxic/cytostatic effect has been reported in different cell types. It is reported that the activity/expression of gamma-glutamylcysteine synthetase (gamma-GCS, the rate-limiting enzyme in GSH biosynthesis) can be inducibly activated by electrophiles, including CP-PGs. The response of the human cancer strains HEp-2 (larynx carcinoma) and HL-60 (promyelocytic leukemia) cells to treatment with the CP-PG PGA1 in culture was investigated by evaluating the time-course of GSH synthesis and activity of enzymes of GSH metabolism, other than gamma-GCS, after PGA1 addition. HEp-2 cells, being more resistant to PGA1 cytotoxic and cytostatic effects, have basal GSH levels that were 2.4-fold higher than that of HL-60 cells. The activities of GSH S-transferase (GST), glutathione reductase (GSRd) and glutathione peroxidase (GSPx) are constitutively higher in HL-60 cells than in HEp-2 cells (respectively, 17.0-, 28.5- and 12.3-fold). When challenged with PGA1, both cell types exhibited a dose-dependent rise in GSH content that was maximal 18 h after PGA1 addition and was preceded by a rise in GST and GSRd activities in both cell types (at 12 h). GSPx activity increased only in HEp-2 (PGA1 evoked a 93.4%-inhibition in HL-60 cells). Moreover only HEp-2 cells exhibited early capacity to enhance GSH content (1-2 h just after PGA1 addition). These results and earlier data showing that leukemia cells are sensitive to CP-PG treatment suggest that deficiencies in GSH metabolism may be strategically in therapeutic approaches to the treatment of human leukemias.

Fish oil given by gavage increases lymphocyte proliferation and production of hydrogen peroxide by rat macrophages.

1. The effect of fish oil (FO) administration by gavage (0.4% body weight) on macrophage and lymphocyte function was investigated in young male rats. The results were compared with those obtained by administration of soybean oil (SB) and cocoa butter (CB). 2. Lymphocyte proliferation was markedly increased by FO administration compared with control and other oils. 3. Macrophage phagocytosis capacity was not affected by FO, but it was increased by CB and SB. 4. The oils did not affect the production of O2.- but increased the production of H2O2 in the presence of PMA. 5. The administration of the oils did not markedly affect the activity of antioxidant enzymes in macrophages, except for a decrease in superoxide dismutase activity by FO.

Effect of the administration of fish oil by gavage on activities of antioxidant enzymes of rat lymphoid organs.

1. The effect of administration of fish oil by gavage on catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities of the lymphoid organs and liver was compared with those of soybean oil and cocoa butter. 2. Fish oil did not affect the activities of SOD and CAT but reduced that of GSH-Px in the spleen. In contrast, cocoa butter reduced the CAT activity in the thymus and liver, and soybean oil decreased CAT activity in the thymus. 3. The content of thiobarbituric acid reactive substances of the lymphoid organs was not modified but was increased in plasma.

Percentage of phagocytosis, production of O2.-, H2O2 and NO, and antioxidant enzyme activities of rat neutrophils in culture.

Changes in the integrity, ultrastructure, phagocytosis capacity, and production of H2O2, O2.- and NO2- were evaluated in cultured neutrophils. The activities of the antioxidant enzymes (catalase-CAT, superoxide dismutase-SOD and glutathione-dependent peroxidase-GSH-Px) were measured under similar conditions. The integrity of the cells remained unchanged up to 18 h. After 24 h, the number of viable cells in culture dropped by 16 per cent. The percentage of viable cells in culture was of 72 per cent even after 72 h. An ultrastructural analysis of the cells was carried out after 3, 6, 12, 24, 48, and 72 h in culture. Neutrophils started developing morphologic changes after 24 h: decreased cell volume, abundant vacuoles (mainly around the nucleus), and also the presence of autophagic vacuoles. This period was then chosen for the study of neutrophil function and antioxidant enzyme activities. Neutrophils cultured for 24 h presented reduced phagocytosis capacity. The rates of production of H2O2 and O2.- remained unchanged after 24 h in culture. Concomitantly, these cells were also able to produce NO in significant amounts. The production of O2.- in response to PMA stimulus was lowered in 24-h cultured cells. Possibly, the production of oxygen and nitrogen reactive species accomplished with a decrease in the activities of CAT and GSH-Px play a key role for the process of apoptosis which takes place in neutrophils under these conditions.

Changes in the activities of antioxidant enzymes of the lymphoid organs of 21-day pregnant rats due to administration of fish oil by gavage.

1. The effect of fish oil administration by gavage (0.4% body weight) on activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH-Px) and on content of thiobarbituric acid reactive substances (TBARs) of the lymphoid organs [thymus, spleen and mesenteric lymph nodes (MLN)] and liver was investigated in 21-day pregnant rats. The results were compared with those obtained by administration of soybean oil, cocoa butter and coconut oil. 2. Oil administration did not have any significant effect on antioxidant enzyme activities of the liver, whereas marked changes were found in the lymphoid organs. The MLN presented the most pronounced changes: SOD and catalase activities were increased by the four oils; GSH-Px activity was raised by soybean and fish oils; coconut oil reduced the activity of the three antioxidant enzymes in this organ. 3. Fish oil given by gavage does affect the antioxidant capacity of the lymphoid organs; however, similar effect was also observed for cocoa butter and soybean oil. These changes in the antioxidant enzyme activities were able to prevent the lipid peroxidation process in the lymphoid organs.