Effects of purified soybean agglutinin on growth and immune function in rats

The objective of this study was to investigate the effect of purified soybean agglutinin on growth and immune function in rats. Thirty male Sprague-Dawley rats (77.8 +/- 2.6 g) were individually fed casein-cornstarch based diets containing 0, 0.05, 0.10, 0.15 or 0.20% soybean agglutinin (w/w) during a 20-day experiment. Growth declined linearly with increasing the concentration of soybean agglutinin (p < 0.05). The proliferation of lymphocytes in spleen, lymph nodes and blood decreased with an increase in dietary soybean agglutinin (p < 0.05). The concentrations of interleukin-2, interferon-gamma and tumor necrosis factor-alpha in plasma, spleen, and mesenteric lymph nodes as well as plasma concentrations of IgA, IgG and IgM also declined with increasing dose of soybean agglutinin (p < 0.05). The results show that dietary soybean agglutinin has negative effects on growth as well as both cell-mediated and humoral immune function of rats and appears to function in a dose-dependent manner.     

Effects of purified soybean agglutinin on growth and immune function in rats

Abstract

The objective of this study was to investigate the effect of purified soybean agglutinin on growth and immune function in rats. Thirty male Sprague-Dawley rats (77.8 ± 2.6 g) were individually fed casein-cornstarch based diets containing 0, 0.05, 0.10, 0.15 or 0.20% soybean agglutinin (w/w) during a 20-day experiment. Growth declined linearly with increasing the concentration of soybean agglutinin (p < 0.05). The proliferation of lymphocytes in spleen, lymph nodes and blood decreased with an increase in dietary soybean agglutinin (p < 0.05). The concentrations of interleukin-2, interferon-γ and tumor necrosis factor- in plasma, spleen, and mesenteric lymph nodes as well as plasma concentrations of IgA, IgG and IgM also declined with increasing dose of soybean agglutinin (p < 0.05). The results show that dietary soybean agglutinin has negative effects on growth as well as both cell-mediated and humoral immune function of rats and appears to function in a dose-dependent manner.     

Effects of soybean glycinin on performance and immune function in early weaned pigs

Glycinin, a major storage protein in soybean, has been identified as an important food allergen. The present study was conducted to investigate the effects of soybean glycinin on the local and systemic immune responses using a swine model specific for glycinin allergy. Performance, peripheral blood lymphocyte proliferation and CD4+ and CD8+ subsets in the plasma of naive and sensitised piglets were determined. In addition, the concentrations of IgA, IgG, IgM, interleukin-4 and interleukin-6 in the jejunum mucosa were measured. Our results showed that dietary supplementation of glycinin reduced piglet performance (p < 0.05), while increasing lymphocyte proliferation and CD4+/ CD8+ ratio (p < 0.01). Intestinal mucosal immune responses to glycinin were enhanced with high levels of IgA (p < 0.01) as well as interleukin-4 and interleukin-6 in the jejunum mucosa in glycinin-treated piglets compared with the control (p < 0.01). There were no differences due to treatment in the densities of IgG and IgM. In conclusion, it was found that glycinin stimulated local and systemic immune responses in allergic piglets and had negative effects on piglet performance. The severity of the immune reactions depends on the dose of glycinin with higher doses causing more severe symptoms.     

Reduction by phytate-reduced soybean beta-conglycinin of plasma triglyceride level of young and adult rats.

This study examined the effects of soybean beta-conglycinin, from which phytate was mostly removed, on the plasma lipids in young and adult rats. Male Wistar young (6 week-old) and adult (21 week-old) rats were fed high cholesterol diets containing 20% casein, soy protein isolate (SPI), or soybean beta-conglycinin for 10 days. In young rats, although the food intake of the beta-conglycinin group was higher than those of the casein and SPI groups, the weight gain was significantly lower than those of the other groups. However, in adult rats, the weight gain was not different among the groups. In young and adult rats, relative liver weights of SPI and beta-conglycinin groups were significantly lower than that of the casein group, and the degree of the reduction was more marked in the beta-conglycinin group than in the SPI group. In young rats, the plasma triglyceride level was significantly lower in the SPI and beta-conglycinin groups than that in the casein group. In addition, the plasma triglyceride level of the beta-conglycinin group was significantly lower than that of the SPI group. Plasma total cholesterol levels of the SPI and beta-conglycinin groups were significantly lower than that of the casein group. However, there was little difference in the lowering effect between SPI and beta-conglycinin. These results indicate that soybean beta-conglycinin may have lowering functions not only on plasma total cholesterol level, but also on plasma triglyceride level.     

Disappearance of immunoreactive glycinin and beta-conglycinin in the digestive tract of piglets

Soybean allergy represents a health threat to human and animals. Glycinin and beta-conglycinin, the main storage proteins in soybean, have been identified as major food/ feed allergens. The present study was conducted to investigate the disappearance of immunoreactive glycinin and beta-conglycinin in the digestive processes of piglets. Twelve crossbred piglets, weaned at 21 days of age, were allocated to three dietary treatments in a complete block design, each treatment with four replicates (female/male = 1:1). From day 22-28, the control group was fed diets without leguminous products, while the two treatment groups received diets containing 2.2% purified glycinin or beta-conglycinin. All piglets were slaughtered at 29 days of age and digesta was sampled from stomach, middle jejunum, caecum and colon. Results indicated that immunoreactive glycinin and beta-conglycinin decreased as the digesta descended down the digestive tract to 0.12% and 0.47%, respectively. Little immunoreactive glycinin was found in the digesta of caecum and colon, while immunoreactive beta-conglycinin was detected in the colon. Along the whole digestive tract the disappearance of immunoreactive glycinin was significantly higher than beta-conglycinin (p < 0.05).     

IgE formation in the rat following infection with Nippostrongylus brasiliensis: I. Proliferation and differentiation of IgE-bearing cells

Sprague-Dawley rats were infected with Nippostrongylus brasiliensis larvae, and IgE formation was studied. Before infection, the serum IgE level was less than 0.4 μg/ml. The IgE level began to increase from the 10th day of infection, reached its maximum (50–100 μg/ml) at the 14th day and gradually declined. Reinfection of the rats resulted in an increase of the serum IgE level within 7 days. The IgE antibody response to N. brasiliensis antigens did not parallel the increase of IgE synthesis. In most animals, the antibody became detectable in the serum at the 21st day when the total IgE level already began to decrease. The animals showed a secondary IgE antibody response upon reinfection. Both mesenteric lymph nodes and spleen cell suspensions were examined for the presence of IgE-bearing cells (IgE-B cells) and IgE-forming cells by fluorescent antibody technique. The IgE-bearing lymphocytes became detectable in the mesenteric lymph nodes and spleen at the 8th day of infection. The proportion of the IgE-B cells in nonadherent cell population gradually increased and reached maximum at the 14th day; about 20% of immunoglobulin (Ig)-bearing cells in the mesenteric lymph nodes and 10% of Ig-bearing cells in spleen bore IgE on their surface. Evidence was obtained that these lymphocytes synthesized IgE. The IgE-forming cells were detected in both mesenteric lymph nodes and spleen of the infected animals. The number of IgE-forming cells was greater in the mesenteric lymph nodes than in spleen, indicating that the regional lymph nodes are the major source of serum IgE in the N. brasiliensis-infected animals.     

Effects of soybean agglutinin on body composition and organ weights in rats

An experiment was conducted to assess the effect of soybean agglutinin dosage level on growth, body composition, plasma lipids, glucose, urea nitrogen content and aminotransferase activities in rats. Male and female rats (n=60) weaned at 19 d were given a dose of 0, 3.5, 7.0, 10.5, or 14.0 mg soybean agglutinin by gastric infusion once daily for 10 days. With increasing doses of soybean agglutinin, body weight, lipid content of carcass, spleen and kidneys relative dry weights decreased, while small intestine and pancreatic weight, the contents of urea nitrogen and triglyceride, and the activities of aspartate aminotransferase linearly increased in plasma. Though soybean agglutinin decreased plasma insulin content, changes in plasma glucose content due to soybean agglutinin were not detected. It is suggested that dietary soybean agglutinin may affect the secretion of other hormones besides insulin, which modulate blood glucose reserves. In conclusion, consumption of soybean agglutinin resulted in a depletion of lipid and an overgrowth of small intestine and pancreas in rats. Meanwhile, poor growth of spleen and kidneys was observed in the soybean agglutinin-fed rats.     

CD8+ T cells modulate late allergic airway responses in Brown Norway rats.

To test the hypothesis that CD8+ T cells may suppress the allergen-induced late airway response (LAR) and airway eosinophilia, we examined the effect of administration of Ag-primed CD8+ T cells on allergic airway responses, bronchoalveolar lavage (BAL) leukocytes, and mRNA expression for cytokines (IL-4, IL-5, and IFN-gamma) in OVA-sensitized Brown Norway rats. On day 12 postsensitization to OVA, test rats were administered 2 million CD8+ T cells i.p. isolated from either the cervical lymph nodes (LN group; n = 8) or the spleen (Spl group; n = 6) of sensitized donors. On day 14, test rats were challenged with aerosolized OVA. Control rats were administered PBS i.p. on day 12, and challenged with OVA (n = 10) or BSA (n = 6) on day 14. The lung resistance was measured for 8 h after challenge. BAL was performed at 8 h. Cytospin slides of BAL were analyzed for major basic protein by immunostaining and for cytokine mRNA by in situ hybridization. The LAR was significantly less in the LN group (1.8 +/- 0.5 U; p < 0.01) and BSA controls (1.4 +/- 0.7; p < 0.01), but not in the Spl group (6.7 +/- 2.2), compared with that in OVA controls (8.1 +/- 1.8). In BAL, the number of major basic protein-positive cells was lower in the LN and Spl groups compared with OVA controls (p < 0.05 and p < 0.01). IL-4- and IL-5-positive cells were decreased in the LN group compared with the OVA controls (p < 0.01). INF-gamma-positive cells were increased in the LN and Spl groups compared with the OVA controls (p < 0.01). Serum OVA-specific IgE levels were unaffected by CD8+ T cell transfers. These results indicate that Ag-primed CD8+ T cells have a potent suppressive effect on LAR.     

Effects of soybean glycinin on performance and immune function in early weaned pigs

Glycinin, a major storage protein in soybean, has been identified as an important food allergen. The present study was conducted to investigate the effects of soybean glycinin on the local and systemic immune responses using a swine model specific for glycinin allergy. Performance, peripheral blood lymphocyte proliferation and CD4⁺ and CD8⁺  subsets in the plasma of naive and sensitised piglets were determined. In addition, the concentrations of IgA, IgG, IgM, interleukin-4 and interleukin-6 in the jejunum mucosa were measured. Our results showed that dietary supplementation of glycinin reduced piglet performance (p < 0.05), while increasing lymphocyte proliferation and CD4⁺/CD8⁺  ratio (p < 0.01). Intestinal mucosal immune responses to glycinin were enhanced with high levels of IgA (p < 0.01) as well as interleukin-4 and interleukin-6 in the jejunum mucosa in glycinin-treated piglets compared with the control (p < 0.01). There were no differences due to treatment in the densities of IgG and IgM. In conclusion, it was found that glycinin stimulated local and systemic immune responses in allergic piglets and had negative effects on piglet performance. The severity of the immune reactions depends on the dose of glycinin with higher doses causing more severe symptoms.     

Effects of chicken intestinal antimicrobial peptides on humoral immunity of chickens and antibody titres after vaccination with infectious bursal disease virus vaccine in chicken

Sixty chickens were randomly divided into two groups (30 chickens in each group) to determine the effect of oral administration of chicken intestinal antimicrobial peptides (CIAMP) on the humoral immune response. Chickens of both groups were fed the same diet. In the treatment group chickens received drinking water supplemented with CIAMP (1 microg/ml) right after hatching. Samples of blood, bursa of Fabricus, spleen and intestine were taken at day 1, 4, 7, 10 and 17 of experiment. CIAMP supplementation enhanced the content of IgG and IgM in serum from day 4-10 and day 10-17, respectively, (p < 0.05), IgM-forming cells in bursa of Fabricus and spleen at the age of 7 days (p < 0.05) and IgG-forming cells in bursa of Fabricus at the age of 4 days (p < 0.05). In addition, CIAMP enhanced the IgA-forming cells in caecal tonsils diffuse area at day 4 (p < 0.05). Furthermore, CIAMP enhanced the antibody response to infectious bursal disease virus vaccine (IBDV) in chickens 21 days following IBDV vaccine administration (p < 0.05). These results suggested that CIAMP could modulate the humoral immune response of chickens and increased the antibody titres of infectious bursal disease virus vaccine.     

In vivo kinetics and nature of rat IgE-bearing lymphocytes after IgE stimulation

Surface IgE-bearing (sIgE+) cells were studied in BN and rnu/rnu athymic rats after Nippostrongylus brasiliensis infection or i.p. injection of unpurified or purified IgE from plasmacytoma ascitic fluid. The number of sIgE+ cells increased markedly after a serum IgE increase without change in the proportion of sIgM+ and sIgD+ cells. A high percentage of the sIgE+ cells bore cytophilic IgE. Receptors for IgE were induced with a 2.56-micrograms IgE injection/100 g body weight and reached a maximum with 1.6 mg IgE/100 g body weight. They appeared less than 4 hr after a single injection of purified IgE. The number of IgE receptor-bearing cells reached a maximum plateau at 24 hr to day 3 after injection and declined thereafter, to reach the control level on day 9 or 11 after injection. Nearly all the sIgE+ cells of BN rats also bore sIgD, but the number of triple sIgE-sIgM-sIgD+ cells varied in a wide range. Maximum 4.5% of the sIgE+ cells of euthymic rats were T cells. More than 98% of the sIgE+ cells of nude rats were triple sIgM-sIgD-sIgE+ cells, and the majority were cytophilic IgE+. For the most part, the sIgM-sIgD-sIgE+ cells are probably not cells that can differentiate, as generally accepted, in IgE-producing cells. New interpretations of the role of these triple sIgM-sIgD-sIgE+ cells in IgE immune responses are necessary.     

A role of IgE and CD23/NO immune pathway in age-related resistance of Lewis rats to Plasmodium berghei Anka?

In contrast to young rats, adult rats given i.p. Plasmodium berghei Anka (PbA) control the parasitaemia and repair their anaemia. Here, we investigated whether IgE and CD23/NO immune pathway could be implicated in this age-related resistance of adult rats to PbA. Eight-week-old rats displayed significantly higher levels of plasma total IgE (p=0.01) and soluble CD23 (p=0.003) during the peak of parasitaemia, compared to 4-week-old rats. IgE Fc-binding antibody or aminoguanidine administration to parasitized 8-week-old rats slightly delayed blood parasite clearance or exacerbated anaemia. These data suggest that IgE and CD23/NO could play an important role in the resistance of adult rats experiencing PbA primary intraerythrocytic development.     

姜黄素对过度训练大鼠脾脏炎症反应的调控作用及其机制

目的:研究姜黄素调控Toll-样受体4(TLR4)-p38丝裂原活化蛋白激酶(p38 MAPK)/核因子κB(NF-κB)信号通路缓解过度训练大鼠脾脏炎症反应的作用及其机制.方法:7周龄SPF级雄性Wistar大鼠分为安静对照组(C组,n=12)、过度训练模型组(OM组,n=11)、姜黄素+模型组(COM组,n=14)...     

Effect of dietary protein on cholesterol homeostasis in diabetic rats

Normal and streptozotocin (STZ)-diabetic rats were studied in order to examine the effects of altering the type of dietary protein on cholesterol homeostasis. Rats were fed a non-purified or a purified diet containing either casein or soybean protein. The results obtained on the specific aspects of lipid metabolism were remarkably similar in control rats fed the non-purified (Purina Lab Chow) diet or the purified diet with the soybean protein. However, most of the findings obtained with the above two groups were different from those obtained with rats fed the purified diet containing casein. In the latter group, plasma cholesterol was elevated following a 15-day feeding period as compared to the other two dietary groups. The excess plasma cholesterol in the casein-fed group was found in two lipoprotein fractions with densities of 1.023-1.045 g/ml and 1.045-1.086 g/ml, respectively. The latter lipoprotein fraction was also enriched with apolipoprotein E. The casein-fed animals also showed a lower fractional rate of plasma cholesterol esterification and an abnormal accumulation of cholesterol in the body despite inhibition of cholesterol synthesis in the liver and in the intestines. Twelve to 15 days after the induction of diabetes, plasma cholesterol increased to a similar extent in the rats on all three diets. However, the distribution of cholesterol among the lipoprotein fractions was markedly different. The percentage of cholesterol in fractions of d less than 1.086 g/ml was increased while that carried in the fraction of d 1.086-1.161 g/ml decreased in the rats fed the nonpurified diet and the casein diet. In contrast, there was no change in the distribution of lipoprotein cholesterol between the diabetic and the control rats fed the soybean protein diet. The hepatic synthesis of cholesterol was unaltered in diabetic rats fed the nonpurified diet and the purified diet with soybean protein, but was increased 2.4-fold in diabetic rats fed casein. Intestinal cholesterol synthesis was increased in all three dietary groups. The increase was highest in the rats fed casein and lowest in rats fed soybean protein. The rate of sterol synthesis in the kidneys was not significantly affected by the diet or diabetes. In all three dietary groups diabetes led to an abnormal accumulation of cholesterol in the body. This accumulation was highest in the casein-fed rats and lowest in those fed the soybean protein diet. The cholesterol content of the kidneys was markedly increased by dietary casein.(ABSTRACT TRUNCATED AT 400 WORDS)     

Preliminary human study for possible alteration of serum immunoglobulin E production in perennial allergic rhinitis with fermented milk prepared with Lactobacillus gasseri TMC0356

The fermented milk prepared with Lactobacillus gasseri TMC0356 was administered at 200 ml per day for 4 weeks to 15 subjects with high serum IgE levels and perennial allergic rhinitis. The serum total IgE concentration was significantly reduced after 28 days' exposure to the fermented milk (P <0.05) compared to that before the intervention. The serum IgE specific to Acari and those to Japanese cedar pollen also significantly declined (P <0.05). T helper 1 (Th1) cells in the composition of their peripheral blood mononuclear cells (PBMCs) significantly increased after 14 days (P <0.01) and after 28 days (P <0.05). These results suggest that the fermented milk prepared with L. gasseri TMC0356 may alter serum IgE concentration, at least partly by enhancement of Th1 immune responses of the subjects with high concentration of serum IgE. However, further studies are still necessary to know the underlying mechanisms by which the tested fermented milk could influence the host immunity.     

Improvement of follicular development rather than gonadotrophin secretion by thyroxine treatment in infertile immature hypothyroid rdw rats

Despite extensive study of reproductive abnormalities in female hypothyroid animals, little is known of folliculogenesis and gonadotrophin secretion in spontaneously hypothyroid animals, especially in response to exogenous hormone treatment. In this study, follicular development and plasma hormone concentrations in the presence or absence of thyroxine and eCG treatment were investigated in infertile immature spontaneously hypothyroid rdw rats. Administration of thyroxine once a day from day 21 to day 29 after birth resulted in increases in body weight (P < 0.001) and ovary mass on day 30 (P < 0.01). Similar populations of both healthy and atretic antral follicles ranging from 101 to 400 micrometer in diameter were observed in control rdw and normal rats. In rdw rats, thyroxine treatment markedly increased the number of healthy antral uniovular follicles 101-400 or > 550 micrometer in diameter in the absence or presence of eCG, respectively. Combined treatment of thyroxine and eCG in rdw rats also markedly increased the number of healthy antral biovular follicles. Thyroxine treatment did not affect the population of atretic antral follicles, but resulted in decrease in the number of atretic large antral follicles (> 400 microm) in the presence of eCG. Plasma oestradiol concentrations in rdw rats given both thyroxine and eCG were significantly higher than they were in rdw rats given eCG alone (P < 0.001). There were no significant differences in plasma FSH concentrations on day 28 between rdw (10.7 +/- 1.6 ng ml(-1)) and normal rats (12.0 +/- 1.4 ng ml(-1); P > 0. 05). Although there were no significant differences in plasma LH concentrations between control rdw (1.9 +/- 0.1 ng ml(-1)) and normal rats on day 30 (1.8 +/- 0.1 ng ml(-1); P > 0.05), eCG treatment increased plasma LH to a peak concentration 52 h after injection in normal (24.9 +/- 2.4 ng ml(-1)) but not in rdw rats treated with thyroxine (4.8 +/- 0.3 ng ml(-1); P < 0.05). In conclusion, the results of the present study indicate that thyroxine treatment improves follicular development but does not rescue the defect of the preovulatory surge of LH in eCG-primed rdw rats.     

In vitro Release of Eosinophil Proteins in Allergic and Atopic Dermatitis Patients

To investigate whether eosinophils are stimulated in vivo or have acquired an increased susceptibility to stimuli from the coagulation cascade, the release of eosinophil proteins was compared for three groups of donors with different levels of serum IgE. (1) with atopic dermatitis (s-IgE > 5000 IU/ml, n = 11); (2) with inhalant allergy (200 < s-IgE < 2 000 IU/ml, n = 10); and (3) non-allergic (s- IgE < 100 IU/ml, n = 10). The levels of eosinophil cationic protein and eosinophil protein X (ECP, EPX) were determined in serum (clotting time = 2.0 h) and plasma. Serum and plasma ECP in normal donors demonstrated large intra-personal variations (C.V. 50-80%), but serum-ECP (mean 8.1 ng/ml) was clearly distinguishable from plasma ECP (mean 1.0 ng/ml) by a factor of 8 (range: 5.6-11.6). The ECP released during clotting was markedly increased in the atopic dermatitis group (serum:plasma ratio 13.5, p < 0.003) compared with the other groups (6.7 and 5.6). EPX, having a higher plasma level, demonstrated a less pronounced release (serum: plasma ratios 2.0, 1.7 and 1.4), with no statistical difference between donor groups. Considering all donors together the levels of ECP and EPX in plasma and in serum were correlated to the number of eosinophils (coefficients of correlation 0.54-0.58, p < 0.002).     

Selectively hydrogenated soybean oil with conjugated linoleic acid modifies body composition and plasma lipids in rats

The present study examined effects of a selectively hydrogenated soybean oil (SHSO) containing about 21% CLA on body composition, adipose depots and organ weights, and plasma lipid profiles in rats. Male Sprague Dawley rats were fed for 6 weeks a purified diet containing 0%, 1%, 3%, and 5% of SHSO. Different levels of SHSO supplementation did not significantly affect growth performance, although there was a trend toward decreased body weight gain with increasing dietary SHSO levels. The weights of inguinal, epididymal, and retroperitoneal adipose depot, but not mesenteric, were significantly influenced by dietary SHSO supplementation (P < 0.05, P < 0.01 and P < 0.001, respectively). Although the absolute weight of body protein in the control rats was higher in SHSO-fed rats, the effect on absolute weight of body protein is diluted and eliminated when the data are adjusted for eviscerated carcass weight as a percentage base. Therefore, as dietary SHSO level increased, body protein as a percentage of carcass weight increased (P < 0.05), although as dietary SHSO level increased, body fat proportion in carcass decreased (P < 0.01). Plasma triglycerides (TG) and total cholesterol (TC) concentrations were beneficially decreased, and HDL-cholesterol (HDL-C) to TC ratio was also beneficially increased by SHSO supplementation (P < 0.05, P < 0.001, and P < 0.01, respectively). However, plasma HDL-C concentration undesirably decreased with dietary SHSO supplementation (P < 0.05). The present study observed that body composition and plasma lipids were beneficially modulated by SHSO supplementation at least 3% levels (0.6% of CLA), and suggested that SHSO is a useful fat source because of the high level of CLA.     

Disassociated increases of adrenomedullin in the rat cerebrospinal fluid and plasma after salt loading and systemic administration of lipopolysaccharide

To determine the role of adrenomedullin (AM) in the fluid electrolyte homeostasis and endotoxin shock, cerebral spinal fluid (CSF) and plasma were sampled from rats after respective challenges. The AM levels were measured by a highly sensitive immunoassay. The AM levels in the CSF of the rats anesthetized with ether (10.7 +/- 0.60 fmol/ml) were significantly higher than those with isoflurane 5.17 +/- 0.70 fmol/ml, P < 0.01), while the plasma level did not differ significantly. The CSF levels of the rats received 2% saline drinking increased to 3 and 4 folds at day 5 and day 7, respectively, while the plasma levels did not differ from controls at both time points. The AM levels in CSF or plasma increased to 1.5 and 3 folds at 1.5 h after intraperitoneal (i.p.) administration of lipopolysaccharide (LPS, 5 mg/kg), reached 6.5 and 30 folds at 6 h, respectively, while no change was observed in the controls. The present findings suggest that AM in the CSF is regulated independently from that in the plasma, the centrally synthesized AM plays and important role in the regulation of the fluid electrolyte homeostasis. Furthermore, the circulatory AM plays an important role in the endotoxin shock.     

Diet enriched with procyanidins enhances antioxidant activity and reduces myocardial post-ischaemic damage in rats

Aim of this work was to study the efficacy of procyanidins from Vitis vinifera seeds, a standardized mixture of polyphenol antioxidants, on cardiac mechanics following ischemia/reperfusion stunning in the rat, after 3 weeks supplementation. Young and aged male rats were fed a diet enriched with procyanidins complexed (1:3 w/w) with soybean lecithin (2.4%); control animals (CTR-young and CTR-aged) received an equal amount of lecithin and 2 additional groups of animals the standard diet. At the end of the treatment, the total plasma antioxidant defense (TRAP), vitamin E, ascorbic acid and uric acid were determined in plasma and the hearts from all groups of animals subjected to moderate ischemia (flow reduction to 1 ml/min for 20 min) and reperfusion (15 ml/min for 30 min). In both young and aged rats supplemented with procyanidins the recovery of left ventricular developed pressure (LVDP) at the end of reperfusion was 93% (p < 0.01) and 74% (p < 0.01) of the preischemic values and the values of coronary perfusion pressure (CPP) were maintained close to those of the preischemic period. Also creatine kinase (CK) outflow was restrained to baseline levels, while a 2-fold increase in prostacyclin (6-keto-PGF1alpha) in the perfusate from hearts of young and aged rats was elicited during both ischemia and reperfusion. In parallel, procyanidins significantly increased the total antioxidant plasma capacity (by 40% in young and by 30% in aged rats) and the plasma levels of ascorbic acid, while tend to reduce vitamin E levels; no significant differences were observed in uric acid levels. The results of this study demonstrate that procyanidins supplementation in the rat (young and aged) makes the heart less susceptible to ischemia/reperfusion damage and that this is positively associated to an increase in plasma antioxidant activity.