Oregano (Origanum vulgare) Essential Oil and Its Constituents Prevent Rat Kidney Tissue Injury and Inflammation Induced by a High Dose of L-Arginine.

This study aimed to evaluate the protective action of oregano (Origanum vulgare) essential oil and its monoterpene constituents (thymol and carvacrol) in L-arginine-induced kidney damage by studying inflammatory and tissue damage parameters. The determination of biochemical markers that reflect kidney function, i.e., serum levels of urea and creatinine, tissue levels of neutrophil-gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1), as well as a panel of oxidative-stress-related and inflammatory biomarkers, was performed. Furthermore, histopathological and immunohistochemical analyses of kidneys obtained from different experimental groups were conducted. Pre-treatment with the investigated compounds prevented an L-arginine-induced increase in serum and tissue kidney damage markers and, additionally, decreased the levels of inflammation-related parameters (TNF-α and nitric oxide concentrations and myeloperoxidase activity). Micromorphological kidney tissue changes correlate with the alterations observed in the biochemical parameters, as well as the expression of CD95 in tubule cells and CD68 in inflammatory infiltrate cells. The present results revealed that oregano essential oil, thymol, and carvacrol exert nephroprotective activity, which could be, to a great extent, associated with their anti-inflammatory, antiradical scavenging, and antiapoptotic action and, above all, due to their ability to lessen the disturbances arising from acute pancreatic damage. Further in-depth studies are needed in order to provide more detailed explanations of the observed activities.

Risk Perception About HIV Among University Students in One of the Last Hotspots for HIV Transmission in Europe.

BACKGROUND: HIV testing in the Northern Kosovo province is challenging, because the infrastructure is being rebuilt after the ethnic conflict. The purpose of this research was to examine self-perceived risk for acquiring HIV infection and factors associated with risk assessment among university students. METHODS: Students completed a questionnaire on socio-demographic data, knowledge about HIV prevention and transmission, attitudes toward people living with (PLHIV) and self-perceived risk for HIV infection. The self-perceived risk was categorized as low, unknown and high. RESULTS: The majority of students (72.5%) assessed their risk as low, 8.5% assessed their risk as high and 19.1% did not know their risk. Compared to low self-perceived risk, high self-perceived HIV risk was associated with being male, having lower knowledge about HIV prevention, less strong Segregation and protection attitude toward PLHIV, stronger Ignorance and indifference attitude toward PLHIV and positive opinion about gays/lesbians. Students who perceived own risk for acquiring HIV as high had lower knowledge about HIV transmission and prevention. However, those who were previously tested for HIV, despite their poorer knowledge about HIV prevention, assess their HIV-related risk as low. CONCLUSIONS: Students assessed their risk of HIV infection mostly as low. Still, lower knowledge of HIV prevention has been consistently associated with a high and unknown risk of HIV. Moreover, being ignorant and indifferent about PLHIV was associated with increased self-perceived HIV risk. These findings highlight the need for continuous specialized HIV-related education to reduce fear and stigma of PLHIV and HIV testing as well as risky behaviors.

Vitamin B complex suppresses neuroinflammation in activated microglia: in vitro and in silico approach combined with dynamical modeling.

Activated microglia is critically involved in the regulation of neuroinflammation/neurodegradation. Hereby, the anti-inflammatory effects of the vitamin B complex (VBC - B1, B2, B3, B5, B6, and B12) on the function and phenotype of lipopolysaccharide (LPS)-stimulated BV2 microglial cells were examined in vitro. Additionally, VBC-treated microglia supernatants were evaluated on SH-SY5Y cells to investigate the effects on neurons' viability. Further, anti-inflammatory mechanisms of VBC were examined by molecular dockingstudies to determine the binding affinity of each VBC component to Toll-like receptor 4 (TLR4) signalling pathway proteins and inducible nitric oxide synthase. In addition, the dynamical model which simulates VBC inhibition of TLR4 signalling pathway proteins activated by LPS has been constructed and excellent agreement with experimental data has been observed (adjR2 = 0.9715 and 0.9909 for TNF-α and IL-6, respectively). The obtained data demonstrated that VBC treatment reduced the inflammatory mediators secreted by LPS-stimulated microglia, diminished their neurotoxic effects against neurons, and induced changes in phenotype profile toward M2 microglia type. Finally, the constructed dynamical model provides deeper insight into the involvement of each VBC component on the VBC inhibitory potential toward the TLR4 signalling pathway and enables optimization of novel VBC formulations as well as inhibitory potential of new putative inhibitors.

Melatonin as a Promising Anti-Inflammatory Agent in an In Vivo Animal Model of Sepsis-Induced Rat Liver Damage.

Melatonin (MLT), earlier described as an effective anti-inflammatory agent, could be a beneficial adjunctive drug for sepsis treatment. This study aimed to determine the effects of MLT application in lipopolysaccharide (LPS)-induced sepsis in Wistar rats by determining the levels of liver tissue pro-inflammatory cytokines (TNF-α, IL-6) and NF-κB as well as hematological parameters indicating the state of sepsis. Additionally, an immunohistological analysis of CD14 molecule expression was conducted. Our research demonstrated that treatment with MLT prevented an LPS-induced increase in pro-inflammatory cytokines TNF-α and IL-6 and NF-κB levels, and in the neutrophil to lymphocyte ratio (NLR). On the other hand, MLT prevented a decrease in the blood lymphocyte number induced by LPS administration. Also, treatment with MLT decreased the liver tissue expression of the CD14 molecule observed after sepsis induction. In summary, in rats with LPS-induced sepsis, MLT was shown to be a significant anti-inflammatory agent with the potential to change the liver's immunological marker expression, thus ameliorating liver function.

Melatonin arrests excessive inflammatory response and apoptosis in lipopolysaccharide-damaged rat liver: A deeper insight into its mechanism of action.

Sepsis is a life-threatening organ dysfunction. An animal model mimicking sepsis utilizes lipopolysaccharide (LPS), an endotoxin recognized as the most potent bacterial mediator of sepsis. Melatonin (MLT), an effective anti-inflammatory and antioxidant agent, is a promising adjunctive drug for sepsis. This study aimed to estimate the potential of MLT in preventing LPS-induced liver damage in Wistar rats by determining the levels of serum and tissue biochemical markers that reflect liver state and function, i.e., serum levels of transaminases and albumin, as well as a panel of oxidative stress-related biomarkers. Additionally, a pathohistological analysis of liver tissue was conducted. Pre-treatment with MLT prevented an LPS-induced increase in serum and tissue liver damage markers and a decrease in the tissue antioxidant capacity, in both enzymatic and non-enzymatic systems. Micromorphological liver tissue changes mirrored the alterations observed in the biochemical status. In rats with LPS-induced sepsis, melatonin was shown to be a crucial antioxidant and anti-inflammatory agent, with vital roles in the alleviation of oxidative stress, causing an increase of the antioxidant capacities and the improvement of the liver's microscopic appearance.

Vitamin B Complex and Experimental Autoimmune Encephalomyelitis -Attenuation of the Clinical Signs and Gut Microbiota Dysbiosis.

The present study aimed to investigate the neuroprotective effects of the vitamin B complex (B1, B2, B3, B5, B6, and B12-VBC), by studying the changes in the femoral nerve, quadriceps muscle, popliteal lymph nodes and gut microbiota in the rat model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). VBC treatment attenuated clinical signs of EAE during the disease, and reduced the duration of EAE thereby contributing to a faster recovery. In VBC-treated EAE rats, a significant decrease in nerve and muscle nuclear density was revealed during the onset period of the disease, while a marked increase was detected at the end of the disease, compared with untreated EAE rats. In the lymph nodes of VBC-treated EAE rats, a fewer number of lymphoid follicles in the cortical area and smaller epithelioid granulomas were detected. The changes in microbiota composition were examined using 16S rRNA gene sequencing and bioinformatics analysis, which revealed the potential of VBC treatment in establishing and/or maintaining gut microbiota homeostasis. Finally, the present study demonstrated that VBC treatment ameliorated the cellular changes in the affected peripheral nerve, muscles innervated by this nerve, and the gut microbiota dysbiosis which occurred during the EAE.

Compliance and approach to voluntary HIV testing in a high-risk region for HIV transmission in Europe.

Background: The Kosovo province is being considered as a high-risk region for the spread of HIV. Objective: To estimate the prevalence and factors associated with HIV testing in a sample of university students from the Serbian northern Kosovo province. Material and Methods: A questionnaire examining socio-demographic characteristics, HIV-related knowledge, attitudes towards people living with HIV (PLHIV) and HIV testing was used in data collection. A total of 1,017 students from the University of Pristina temporarily seated in Kosovska Mitrovica completed the questionnaire. Results: Only 5.4% of students have previously been tested for HIV, even though the majority (70.9%) had a positive approach to HIV testing. Factors associated with having been tested for HIV were being male and younger, having interest in HIV testing and having previous contact with PLHIV. Being more knowledgeable about HIV and having stronger positive attitude towards PLHIV, being older, receiving information about HIV through friends and special educational programs, using condom at last sexual intercourse, having positive opinion on gays/lesbians and previous contact with PLHIV were associated with positive approach to HIV testing. Conclusion: Having a positive approach to HIV testing does not suggest that students would take the HIV test. However, students who have low HIV-related knowledge, negative approach or lack of interest in HIV testing (believing that there is no need to take it) would likely never take the HIV test. Increasing HIV-related knowledge, acceptance of PLHIV and access to testing facilities should be public health priorities to raise HIV testing rates.

Methyl and Isopropyl N-Methylanthranilates Affect Primary Macrophage Function - An Insight into the Possible Immunomodulatory Mode of Action.

To complement the knowledge on the anti-inflammatory activity of methyl and isopropyl N-methylanthranilates, two natural products with panacea-like properties, we investigated their effects on thioglycolate-elicited macrophages by evaluating macrophage ability to metabolize MTT, macrophage membrane function, and macrophage myeloperoxidase and phagocytic activities. Moreover, two additional aspects of the inflammatory response of these compounds, their inhibitory activity on xanthine oxidase and catalase, were studied. It was found that these two compounds regulate elicited macrophage functions, most probably by interfering with the function of cell membranes and changing the reducing cellular capacity or enzyme activity of macrophages. Nonetheless, no significant inhibitory action either towards xanthine oxidase or catalase was found, suggesting that the inhibition of these enzymes is not involved in the anti-inflammatory mode of action of these two esters.

Thymol regulates the functions of immune cells in the rat peritoneal cavity after l-arginine-induced pancreatitis.

AIMS: The present study aimed to evaluate the protective action of thymol towards l-arginine-induced acute pancreatitis (AP) by studying the function of rat peritoneal immune cells. MAIN METHODS: Rat peritoneal exudate cells (PECs), obtained 24 h after the injection of l-arginine (350 mg/100 g of b.w.), were evaluated for mitochondrial activity (MTT assay), adherence capacity (methylene-blue assay), and phagocyte enzyme activity (myeloperoxidase, MPO, assay). The activity of α-amylase and free MPO, as well as the concentration of reactive oxygen species (ROS, i.e. O2-), were determined in the peritoneal exudate fluid. Also, serum α-amylase activity determination and pancreatic tissue pathohistological analysis were performed. KEY FINDING: The administered thymol (50 and 100 mg/kg, per os) caused a significant decrease in the PEC mitochondrial activity and adherence capacity when compared with these functions of PECs isolated from rats with AP. A decrease in cellular MPO activity, as well as in the levels of ROS, α-amylase, and free MPO in peritoneal exudates was found in animals treated with thymol compared to the control animals with AP. Additionally, thymol administration prevented an increase in serum α-amylase activity, accompanied by the decrease in pancreatic tissue damage that follows l-arginine application. SIGNIFICANCE: The present results showed that thymol exerts significant immunomodulatory properties and a potential to silence PEC functions in inflammatory conditions such as the AP induced by l-arginine.

Effects of oleuropein on rat's atria and thoracic aorta: a study of antihypertensive mechanisms.

Oleuropein (OLE) is the main bioactive ingredient in the leaves of the olive plant Olea europaea L. (Oleaceae), which has proven beneficial due to the antiinflammatory, antiatherogenic, anticancer, antimicrobial, and antiviral effects. This study aimed to investigate the antihypertensive and vasodilator potential of OLE by analyzing its acute effects on spontaneous atrial contractions and vasomotor responses of the isolated thoracic aorta in rats. We showed that the application of OLE induces negative chronotropic and inotropic effects on the heart. OLE also causes mild aortic vasodilation given that the maximal reduction in tension of intact aortic rings precontracted with phenylephrine was approximately 30%. This vasodilation is likely dependent on the nitric oxide released from the endothelium based on the effect obtained on denuded and phenylephrine precontracted aortic rings and responses reordered following vasoconstriction induced by high concentrations of K+ and heparin. Our findings provide a basis for further testing of OLE cardiovascular effects, which may lead to subsequent clinical research for its application in the treatment of hypertension and heart disease.

Relevance of students' demographic characteristics, sources of information and personal attitudes towards HIV testing for HIV knowledge: evidence from a post-conflict setting.

Although studies on HIV knowledge have previously been conducted in central Serbia and southern Kosovo, none has included the Serbian population residing in the northern part of the Kosovo province. The aim of this study was to assess HIV-related knowledge and to estimate factors contributing to a higher HIV-related knowledge level among Serbian university students in the Kosovo province. A cross-sectional study including 1017 first- and fourth-year students enrolled at the University of Pristina temporarily seated in Kosovska Mitrovica was carried out during the academic year 2013-2014. The students completed a 31-item questionnaire comprising demographic data, HIV transmission knowledge and attitude towards HIV testing. Data were statistically analysed. Students demonstrated good knowledge of HIV (average 32.8 ± 3.3 out of a maximum 42). Only 5% of the students reported having been tested for HIV. Factors associated with being more knowledgeable about HIV were studying health-related disciplines (ß = -0.09; 95% confidence interval [CI] -0.13, 0.00), using the internet as a source of information about HIV (ß = -1.09; 95% CI -1.65, -0.52), having a positive attitude towards HIV testing (ß = -0.43; 95% CI -0.59, -0.26), having a low self-perceived risk for HIV infection (ß = 0.41; 95% CI 0.23, 0.56) and the position that one would keep the same level of contact with an HIV-positive person after learning their HIV status (ß = 0.38; 95% CI 0.21, 0.55). Setting up specialized classes on this topic at high schools and universities could help to increase the awareness of HIV infection and promote HIV testing and a positive attitude towards HIV-positive persons.

Positive attitudes towards persons living with HIV in North Kosovo: The university students' perspective.

HIV-related stigma could delay the identification and treatment of persons living with HIV (PLHIV), particularly in regions affected by ethnic conflicts. The aims of this study were to assess attitudes towards PLHIV and examine factors associated with stronger positive attitudes towards PLHIV among university students in the Serbian province of Kosovo. A cross-sectional study was conducted at the University of Pristina temporarily settled in Kosovska Mitrovica during the academic year 2013-2014. A total of 1,017 first- and fourth-year students completed an anonymous questionnaire about socio-demographic characteristics, PLHIV, high-risk groups for acquiring HIV and health behaviour. The main outcome measure was the Attitude Score (ATS), calculated as a sum of points awarded for all attitude-related items. The majority of students (84%) expressed positive attitudes towards PLHIV, while others were indecisive. Most students held negative opinions about persons who use drugs (64%), homosexual persons of both genders (50%) and sex workers (42%). Being female (odds ratio [OR] = 1.49, 95% confidence interval [CI] 1.05-2.09) and older (OR = 1.13, 95% CI 1.03-1.24), not doing paid work while studying (OR = 3.35, 95% CI = 1.63-6.84), studying health-related disciplines (ß = -0.113, 95% CI = -0.085 to -2.747), having stronger positive attitudes towards homosexual persons of both genders (OR = 0.77, 95% CI = 0.64-0.94) and not using illicit drugs (ß = 2.08, 95% CI = 1.03-4.20) were associated with stronger positive attitudes towards PLHIV. Social inclusion of PLHIV and individuals at high risk for acquiring HIV could help reduce the HIV-related stigma.

Immunomodulatory Constituents of Conocephalum conicum (Snake Liverwort) and the Relationship of Isolepidozenes to Germacranes and Humulanes.

Structural elucidation of three new sesquiterpenoids, namely, (1Z,4E)-lepidoza-1(10),4-dien-14-ol (1), rel-(1(10)Z,4S,5E,7R)-germacra-1(10),6 diene-11,14-diol (2), and rel-(1(10)Z,4S,5E,7R)-humula-1(10),5-diene-7,14-diol (3), isolated from the liverwort Conocephalum conicum, was accomplished by a combination of extensive NMR experiments, 1H NMR simulation, and other means. Additionally, the change of the identity of bicyclogermacren-14-al, previously reported as a C. conicum constituent, to isolepidozen-14-al is proposed. Compounds 2 and 3 appear to be related to 1 via hydration involving a shared intermediate, a substituted cyclopropylmethyl cation, formed by a highly regio- and stereoselective protonation of 1, followed by a stereospecific fission of the three-membered ring. In other words, an isolepidozene derivative might be a branchpoint to humulanes and germacranes; this transformation could be of, up to now, unknown, biosynthetic and/or synthetic relevance. Multivariate statistical analysis of the compositional data of C. conicum extract constituents was used to probe the hypothesized biochemical relations. The immunomodulatory effect of 1-3 and conocephalenol (4) was evaluated in an in vitro model on both nonstimulated and mitogen-stimulated rat splenocytes. The compounds displayed varying degrees of cytotoxicity to nonstimulated splenocytes, whereas 2 and 3 were found to exert immunosuppressive effects on concanavalin A-stimulated splenocytes while not being cytotoxic at the same concentrations.

Patterns of condom use in a university student population residing in a high-risk area for HIV infection.

OBJECTIVE: The study objective was to investigate factors associated with condom use among university students. METHODS: During the 2013-2014 academic year, 1017 first and fourth year students from the University of Pristina temporarily seated in Kosovska Mitrovica, northern Kosovo, completed a questionnaire on sociodemographic data, HIV-related knowledge, attitudes and risky behaviours. RESULTS: Condom use during the most recent sexual encounter and with casual partners was reported by just over half of participants. Factors associated with condom use during the most recent sexual encounter were: being male (35.1%), using medical sources of information about HIV (35.7%), having a positive approach to HIV testing (40.1%) and a positive attitude towards sex workers (17.7%), as well as not having had a sexually transmitted infection in the past year (54.2%). Factors associated with more frequent condom use with casual partners were: being single (28.9%), not living in a rented apartment or own home (32.1%), frequenting night clubs at the weekend (35.3%), not using drugs/opioids (54.1%), not being sure whether to keep a contact after learning of their HIV-positive status (10.1%), and having stronger opinions (either positive or negative) on homosexual individuals (15.5% and 32.1%, respectively), sex workers (18.7% and 23.9%, respectively) and drug users (13.2% and 36.5%, respectively). CONCLUSION: Condom use among students in northern Kosovo was low. Strategies for HIV prevention should be focussed on promoting healthy behaviours, especially among female students and students who live alone while at university. Moreover, sexuality education should be carried out in schools and primary health care centres to provide support and enable young people to negotiate safe sex.

Low dose of carvacrol prevents rat pancreas tissue damage after L-arginine application, while higher doses cause pancreatic tissue impairment.

Carvacrol (5-isopropyl-2-methylphenol) is a biologically active monoterpene phenol abundantly present in the essential oils of many Lamiaceae aromatic/ethnomedicinal plants. Herein, we aimed to evaluate the damaging effect of carvacrol to rat pancreatic tissue, but also to assess its possible ameliorative impact on pancreatic damage induced by L-arginine. The toxic and beneficial (in a dose of 10 mg/kg) properties of carvacrol were assessed by measuring serum α-amylase and lipase activities, tissue malondialdehyde (MDA) content, and pathohistological changes in pancreatic tissue. Application of 100/500 mg/kg of carvacrol produced a significant increase in α-amylase activity, followed by inflammatory-cell infiltration and patchy interlobular edema in the pancreas. In the L-arginine-induced pancreatitis model, a dose of 10 mg/kg of carvacrol prevented an increase in α-amylase and lipase activities, and MDA formation, when compared to the animals that received L-arginine only. Animals treated with carvacrol prior to L-arginine administration displayed mild edema and inflammatory infiltration with few necrotic areas. Contrary to that, animals that received only L-arginine showed a massive leukocyte infiltrate with edema and substantial necrotic areas. In our study carvacrol showed significant protective effects and a potential to modulate leukocyte recruitment in pancreatic tissue after L-arginine injection.

Immune response to gut Escherichia coli and susceptibility to adjuvant arthritis in the rats.

We have investigated the humoral immune response to antigens of predominant gut aerobic bacterial strains (i.e. Escherichia coli) over the course of adjuvant arthritis and oil-induced arthritis in two inbred rat strains: Dark Agouti (DA) and Albino Oxford (AO). We report the presence of antibodies specific to proteins of E. coli in molecular weight range between 20-30 kDa in sera of diseased DA rats, and the absence of these antibodies in the sera of AO rats. In DA rats, CFA and IFA provoked a stronger antibody response to E. coli, especially of the IgG2b antibody class. Intramuscular administration of E. coli preceding the adjuvant arthritis induction had no effect on the development and course of disease, as well as on the activation of T cells in the draining inguinal lymph nodes. Higher serum levels of natural and induced IgA antibodies, combined with a higher CD3+CD26+ cell percentage were found in AO rats. The observed correlation between the serologic response to commensal flora and rats' genetic background as a defining factor for arthritis susceptibility may contribute to the process of creating a favorable (or less favorable) milieu for arthritis development.

Role of Mast Cells and C-Sensory Fibers in Concanavalin A-Induced Paw Edema in Two Rat Strains.

This study investigated a putative contribution of mast cells and C-sensory fibers to differences in the development of inflammatory edema following the injection of concanavalin A (Con A) into the hind paws of Dark Agouti (DA) and Albino Oxford (AO) rats. The treatment of adult rats with mast cell-depletor compound 48/80 and neonatal depletion of C-sensory fibers independently revealed that leukocyte composition of the inflamed paws and lymph nodes during local inflammatory response to Con A was generally regulated in a similar way in DA and AO rat strains. However, in DA and AO rats, the decrease and the increase of Con A-induced plasma extravasation were associated with mast cell depletion and activation, respectively, whereas neonatal capsaicin treatment activated dermal mast cells and potentiated inflammatory plasma extravasation only in adult rats of DA strain. Hence, strain differences in the development of the inflammatory response to Con A are probably controlled by the differences in the interplay between mast cells and C-sensory fibers in DA and AO rats.

Peritoneal mast cell degranulation differently affected thioglycollate-induced macrophage phenotype and activity in Dark Agouti and Albino Oxford rats.

AIMS: Macrophages are heterogeneous population of inflammatory cells and, in response to the microenvironment, become differentially activated. The objective of the study was to explore macrophage effector functions during different inflammatory conditions in two rat strains. MAIN METHODS: We have investigated the effects of in vivo treatment with mast cell-degranulating compound 48/80 and/or thioglycollate on peritoneal macrophage phagocytosis and capacity to secrete hydrogen peroxide (H2O2), tumor necrosis factor-α (TNF-α) and nitric oxide (NO) in Dark Agouti (DA) and Albino Oxford (AO) rat strains. Besides, fresh peritoneal cells were examined for the expression of ED1, ED2 and CD86 molecules. KEY FINDINGS: In thioglycollate-elicited macrophages, increased proportion of ED1+ cells was accompanied with elevated phagocytosis of zymosan (DA strain), whereas increased expression level of CD86 molecule on ED2+ macrophages matched elevated secretory capacity for H2O2, TNF-α and NO (AO rats). Although mast cell degranulation induced by compound 48/80 increased the percentages of ED2+ macrophages in both rat strains, the proportion of ED2+ cells expressing CD86 molecule was decreased and increased in DA and AO rats, respectively. Furthermore, in DA strain compound 48/80 diminished macrophage secretion of NO, but stimulated all macrophage functions tested in AO strain. If applied concomitantly, the compound 48/80 additively increased macrophage activity induced by thioglycollate in AO rats. SIGNIFICANCE: Macrophages from DA and AO rat strains show different susceptibility to mediators released from mast cells, suggesting that strain-dependant predisposition(s) toward particular activation pattern is decisive for the macrophage efficacy in response to inflammatory agents.

Strain differences in the humoral immune response to commensal bacterial antigens in rats.

We have investigated the immune response to commensal bacterial species in the two inbred rat strains: Dark Agouti (DA) and Albino Oxford (AO). The predominant Gram-negative aerobe in our rats' intestinal bacterial flora was Escherichia coli, while Proteus mirabilis was isolated only from DA rat strain. We report that sera from both DA and AO rat strains contain specific IgG against predominant intestinal flora. Intramuscular administration of commensal bacterial antigens provoked only Th1-type antibody response in AO rats while DA rats developed mixed Th1- and Th2-type antibody response to E. coli and Th1-type response to P. mirabilis antigens. Weaker antibody production to own E. coli and higher serum levels of natural IgG and IgA P. mirabilis-specific antibodies combined with higher CD3+ cells proliferation was found in AO rats. Strain difference in the pattern of antibody production and differential regulation of immune response to commensal bacteria may contribute to the marked differences in the immune reactivity of AO and DA rats.

The influence of aging and estradiol to progesterone ratio on rat macrophage phenotypic profile and NO and TNF-α production.

The phenotype and function of tissue macrophages substantially depend on the cellular milieu and biological effector molecules, such as steroid hormones, to which they are exposed. Furthermore, in female rats, aging is associated with the altered macrophage functioning and the increased estrogen level is followed by a decrease in that of progesterone. Therefore, the present study aimed to investigate the influence of estradiol/progesterone balance on rat macrophage function and phenotype throughout whole adult lifespan. We ovariectomized rats at the late prepubertal age or at the very end of reproductive lifespan, and examined the expression of ED2 (CD163, a marker of mature resident macrophages related to secretion of inflammatory mediators) on peritoneal macrophages and their ability to produce TNF-α and NO upon LPS-stimulation at different age points. In addition, to delineate direct and indirect effects of estrogen, we assessed the in vitro influence of different concentrations of 17ß-estradiol on LPS-induced macrophage TNF-α and NO production. Results showed that: (a) the low frequency of ED2(high) cells amongst peritoneal macrophages of aged rats was accompanied with the reduced TNF-α, but not NO production; (b) estradiol level gradually increased following ovariectomy; (c) macrophage ED2 expression and TNF-α production were dependent on estradiol/progesterone balance and they changed in the same direction; (d) changes in estradiol/progesterone balance differentially affected macrophages TNF-α and NO production; and (e) estradiol exerted pro-inflammatory and anti-inflammatory effects on macrophages in vivo and in vitro, respectively. Overall, our study discloses that estradiol/progesterone balance contributes to the fine-tuning of rat macrophage secretory capacity, and adds to a better understanding of the ovarian steroid hormone role in the regulation of macrophage function, and its significance for the age-associated changes in innate immunity.