Impact of Lithium on the Immune System: An Investigation of T-Cell Subpopulations and Cytokine Responses in Rats.

The aim of this study was to investigate the dose-dependent adverse effects of long-term dietary lithium administration on specific aspects of the defense system in rats. Additionally, the study aimed to explore the inflammatory activities of lithium beyond its recognized anti-inflammatory properties. Forty Wistar Albino rats were involved, which were randomly allocated into the control and four treatment groups. The control group received standard rat feed, and the experimental groups' diet was added 1 g/kg, 1.4 g/kg, 1.8 g/kg, and 2.2 g/kg lithium bicarbonate, respectively. CD4+, CD8+, and CD161 + cells were assessed by flow cytometry. TNF-α, IFN-γ, IL-1ß, and IL-2 and IL-4, IL-6, and IL-10 levels were measured. The proportion of CD4 + cells and the CD4+/CD8 + ratio (P = 0.005 and P = 0.038, respectively) were reduced with the highest dose of lithium compared to the control group. The data regarding pro-inflammatory cytokines showed a dose-dependent increase in serum TNF-α and IFN-γ levels (P = 0.023 and P = 0.001, respectively). On the other hand, serum IL-1ß and IL-2 levels were decreased in a dose-dependent manner (P = 0. 001 and P = 0. 001, respectively). As for anti-inflammatory cytokines, a dose-dependent decrease was determined in serum IL-4 level (P = 0.002), while no significant changes were noted in IL-6 and IL-10 levels (P = 0.507 and P = 0.732, respectively). In conclusion, lithium adversely impacted the cellular defense system. Furthermore, apart from its anti-inflammatory properties, lithium exhibited cytokine-mediated inflammatory activities. Therefore, lithium's potential adverse effects on the immune system should be considered in immunodeficient patients and those with an inflammatory status treated with high doses of lithium.

Impact of chronic lithium treatment on brain oxidative stress and anxiety-like behaviors in rats: Dose-dependent effects.

Lithium (Li) is a mood-stabilizing drug. Although one of the potential mechanisms underlying the neuroprotective effects of lithium is related to its antioxidative effect, its mechanisms of action are not fully understood. Herein we aimed to investigate the impact of varied dosages of long-term lithium therapy on oxidative stress parameters in the brains of healthy rats, and on anxiety-like behaviors, and whether any changes in behavior can be attributed to modifications in oxidative stress levels within the brain. Thirty-two adult Wistar albino male rats were randomly assigned to four treatment groups. While the control (C) group was fed with a standard diet, low Li (1.4 g/kg/diet), moderate Li (1.8 g/kg/diet), and high Li (2.2 g/kg/diet) groups were fed with lithium bicarbonate (Li2CO3) for 30 days. Malondialdehyde increased, while superoxide dismutase and catalase levels decreased in the brains of the high Li group animals. In addition, anxiety-like behaviors of animals increased in the high Li group considering fewer entries to and less time spent in the open arms of the elevated plus maze test. Our findings underscore the potential adverse effects of prolonged lithium treatment, especially at doses approaching the upper therapeutic range. The induction of toxicity, manifested through heightened oxidative stress, appears to be a key mechanism contributing to the observed increase in anxiety-like behaviors. Consequently, caution is warranted when considering extended lithium therapy at higher doses, emphasizing the need for further research to delineate the precise mechanisms underlying these effects and to inform safer therapeutic practices.

In Vivo Pathogenicity of Methicillin-Susceptible Staphylococcus aureus Strains Carrying Panton-Valentine Leukocidin Gene.

Toxin-producing Staphylococcus aureus strains posing a potential risk for public health have long been a topic of scientific research. Effects of Panton-Valentine leukocidin (PVL) on tissue destruction mechanisms and activities of inflammatory cells were presented in animal models of pneumonia and skin infections induced by PVL-producing S. aureus strains. This study aimed to demonstrate the in vivo pathogenicity of PVL-producing S. aureus strains isolated from some foodstuffs, which can be a potential risk to public health. PVL-positive methicillin-susceptible S. aureus (MSSA) strains M1 and YF1B-b isolated from different foodstuffs and a PVL-positive MSSA strain HT480 (positive control) were administered to New Zealand rabbits. Blood samples were harvested three and six hours after the intratracheal inoculation. Lung tissue samples were collected for gross and microscopic exams and immunohistochemical (IHC) demonstration of IL-6, IL8, IL-10, and TNF-α expressions. Serum cytokine levels were also measured by ELISA. The strains isolated from lung tissue samples were confirmed by pulsed-field gel electrophoresis. The development of acute necrotising pneumonia and a significant elevation in IL-6, IL-8, IL-10, and TNF-α expressions demonstrated the significance of foodborne PVL-positive MSSA strains in public health for the first time.

Erythropoietin Protects the Kidney by Regulating the Effect of TNF-α in L-NAME-Induced Hypertensive Rats.

BACKGROUND/AIMS: Hypertension is the leading cause of death worldwide. Chronic high blood pressure induces inflammation. Tumor necrosis factor (TNF)-α plays a major role in inflammation and also depresses the synthesis of erythropoietin, which exerts protective effects on tissue; however, the mechanism is still unclear. We investigated the protective effect of erythropoietin against tissue damage caused by hypertension in the kidney and whether this effect was suppressed by TNF-α. METHODS: First, we detected the optimum chronic dose for darbepoetin-α (Depo), which is a long-acting erythropoietin analog for rats. We separated 60 female adult rats into 6 groups: control, Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME), L-NAME+Depo, L-NAME+Remicade (an anti-TNF-α antibody), L-NAME+Depo+Remicade, Depo, and control. After 1 month of treatment, we measured cardiovascular parameters, took blood samples, sacrificed the rats, and removed kidneys for analyses. RESULTS: The apoptotic index and the plasma and kidney mRNA levels of TNF-α increased in the L-NAME group and decreased in all other treatment groups. Macrophage accumulation increased in the L-NAME and L-NAME+Remicade groups, while it decreased in the Depo group. The mRNA abundance of TNF receptor 1 (TNFR1) decreased slightly in the Depo group and TNFR2 increased significantly in the same group. CONCLUSION: Erythropoietin protects kidney tissue against hypertension by preventing the apoptotic effects of TNF-α by blocking macrophage accumulation, decreasing TNF-α levels, and switching the TNF-α receptors from the apoptotic receptor TNFR1 to the proliferative receptor TNFR2.

Serological and molecular investigation of Ehrlichia spp. and Anaplasma spp. in ticks and blood of dogs, in the Thrace Region of Turkey.

In recent years, tick-borne diseases like ehrlichiosis and anaplasmosis became widespread worldwide threatening the health of both human and companion animals. Therefore, the aim of this study was to determine the presence of Anaplasma spp., and Ehrlichia spp. in dogs and ticks in the Thrace Region of Turkey. A total of 400 blood samples and 912 ticks were collected from dogs living in shelters that are located in four cities (Istanbul, Edirne, Tekirdag and Kirklareli) of the Thrace Region. Blood and buffy coat smears were prepared for microscopic examination. Hematologic and serologic analyses were performed using cell counter and commercial Snap3Dx test kit, respectively. Eight hundred fifty of collected ticks were classified as Rhipicephalus sanguineus, 33 as Rhipicephalus turanicus and 29 as Ixodes ricinus. After DNA extraction from blood samples and pooled ticks (127 tick pools, in total), nested PCR was performed to detect the DNA of Anaplasma spp., and Ehrlichia spp. The seroprevalence of Ehrlichia canis was 27.25% (109) by Snap3Dx test and the total molecular positivity was 11.75% (47) in dog blood samples and 21.25% (27) in tick pools by nested PCR. The frequencies of the infected blood samples with E. canis, Anaplasma phagocytophilum and Anaplasma platys were detected as 6%, 4% and 6%, respectively. E. canis and A. platys were detected in R. sanguineus pools with a ratio of 15.75% and 0.7%, respectively. In addition, A. platys was also detected in R. turanicus pools (0.7%). A. phagocytophilum was found only in I. ricinus pools (3.93%). Morulae of three species were detected in buffy coat and blood smears. While anemia was observed in dogs infected with E. canis and co-infected (with one or more species), thrombocytopenia was observed only in co-infected dogs. This is the first study providing evidence for the presence of Anaplasma spp. and Ehrlichia spp. in dogs and ticks in the Thrace Region of Turkey. Based on the results of the tests used in this study, we recommend the combined use of serologic, molecular, cytologic, hematologic analyses and physical examination of tick exposure for an accurate diagnosis of ehrlichiosis and anaplasmosis.

The effects of environmental enrichment and transport stress on the weights of lymphoid organs, cell-mediated immune response, heterophil functions and antibody production in laying hens.

The effects of environmental enrichment and transport stress on the immune system were investigated in laying hens. A total of 48 1-day-old chickens were used, half of the chickens were reared in conventional cages (RCC) and the rest in enriched cages (REC). Transport stress was applied in the 17th week. Liver weight decreased, spleen and bursa of Fabricius weights, white blood cell count, CD4+ and CD8+ cell proportions increased due to the transport. Environmental enrichment significantly increased antibody production and tended to increase monocyte percentage and CD8+ cell proportion. The effect of transport on, heterophil (H) and lymphocyte (L) percentages was not significant in RCC chickens. While heterophil percentage and H:L ratio increased, lymphocyte percentage decreased in REC chickens subjected to transport. Transport stress increased heterophil functions both in REC and RCC chickens, but the increase was higher in REC hens than in RCC hens. In conclusion, although environmental enrichment did not neutralize the effect of transport on lymphoid organs, it activated the non-specific immune system, cellular and the humoral branches of the specific immune system by increasing heterophil functions, CD8+ cells and antibody production, respectively. Therefore, environmental enrichment suggested for improving animal welfare may also be beneficial to improve the immune system of birds exposed to stress.

The effect of furnished cages on the immune response of laying hens under social stress.

The aim of the study was to examine the effects of cage furnishing and social stress on some lymphoid organ weight and innate, cell-mediated, and humoral immune responses in laying hens. Sixty-four chickens were used. The chickens were divided into 2 groups; one of the groups was reared in furnished cages (RFC) and the other was reared in conventional cages (RCC). In wk 17, social stress was applied. Heterophil and lymphocyte percentages; liver, spleen, thymus, and bursa of Fabricius weights; phagocytic activity; oxidative burst and chemotaxic activity of heterophil; CD4+ and CD8+ cell proportions; and antibody production were measured. The effect of rearing methods was significant on heterophil, lymphocyte percentage, heterophil/lymphocyte (H/L) ratio, and antibody production. Heterophil percentage and H/L ratio were lower (P=0.001, P=0.001, respectively), and antibody production was higher (P=0.003) in RFC hens compared to RCC hens. The main effect of social stress was also significant on heterophil, lymphocyte percentages, and H/L ratio. Heterophil percentage was higher (P=0.049); H/L ratio tended to be higher (P=0.068); and lymphocyte percentage tended to be lower (P=0.072) due to stress. In addition, thymus and bursa of Fabricius weights tended to be lower (P=0.073 and P=0.074, respectively) in stressed hens. There were significant interactions between rearing methods and social stress on oxidative burst, chemotaxic activity, and CD4+ and CD8+ proportion (P=0.001, P=0.004, P=0.054, and P=0.001, respectively). These parameters were significantly higher in RFC hens, when they were exposed to stress. On the other hand, they did not differ in RCC or unstressed RFC hens. These results indicated that cage furnishing positively affected heterophil functions, CD4+ and CD8+ cell proportions, and antibody production. Therefore, we suggest that cage furnishing, which is recommended for improving the welfare of animals, is also beneficial for improving the immune response of hens under the stress condition.

Noise stress changes mRNA expressions of corticotropin-releasing hormone, its receptors in amygdala, and anxiety-related behaviors.

Noise is a psychological, environmental stressor that activates limbic sites in the brain. Limbic sites such as the amygdala and the amygdaloid corticotropin-releasing hormone (CRH) system play an important role in integrating stress response. We investigated the association between noise exposures, CRH-related molecules in the amygdala, and behavioral alterations. In total 54 Sprague-Dawley rats were divided into the following three groups: Control (CON), acute noise exposure (ANE), and chronic noise exposure (CNE). The ANE group was exposed to 100 dB white noise only once in 4 h and the CNE group was exposed to the same for 4 h per day for 30 days. Expression profiles of CRH and its receptors CRH-R1 and CRH-R2 were analyzed by quantitative real-time polymerase chain reaction (qPCR). The same stress procedure was applied to the ANE and CNE groups for behavior testing. The anxiety responses of the animals after acute and chronic stress exposure were measured in the defensive withdrawal test. CNE upregulated CRH and CRH-R1 mRNA levels but downregulated CRH-R2 mRNA levels. ANE led to a decrease in both CRH-R1 and CRH-R2 expression. In the defensive withdrawal test, while the ANE increased, CNE reduced anxiety-like behaviors. The present study shows that the exposure of rats to white noise (100 dB) leads to behavioral alterations and molecule-specific changes in the CRH system. Behavioral alterations can be related to these molecular changes in the amygdala.

The effects of resveratrol on tissue injury, oxidative damage, and pro-inflammatory cytokines in an experimental model of acute pancreatitis.

Acute pancreatitis (AP) is an acute inflammatory condition that results from the digestion of pancreatic tissue by its own enzymes released from the acinar cells. The objective of this study was to investigate the effects of resveratrol on oxidative damage, pro-inflammatory cytokines, and tissue injury involved with AP induced in a rat model using sodium taurocholate (n = 60). There were three treatment groups with 20 rats per group. Groups I and II received 3% sodium taurocholate solution, while group III underwent the same surgical procedure yet did not receive sodium taurocholate. In addition, group II received 30 mg/kg resveratrol solution. Rats were sacrificed at 2, 6, 12, and 24 h time points following the induction of AP. Blood and pancreatic tissue samples were collected and subjected to biochemical assays, Western blot assays, and histopathologic evaluations. Resveratrol did not reduce trypsin levels and prevent tissue damage. Resveratrol prevented IκB degradation (except for 6 h) and decreased nuclear factor-κB (NF-κB), activator protein-1 (AP-1) (except for 24 h), and levels of TNF-α, IL-6 (except for 24 h), and iNOS in the pancreatic tissue at all time points (P < 0.05). Serum nitric oxide (NO) levels were reduced as well (P < 0.05). Thus, we concluded that resveratrol did not reduce trypsin levels and did not prevent tissue injury despite the reduction in oxidative damage and pro-inflammatory cytokine levels detected in this model of AP.

Transmission of stress between cagemates: a study in rats.

The neuroendocrine responses triggered by stressors cause significant behavioral changes in animals. Considering the continuous behavioral interaction between social animals, it would be reasonable to suggest that the aforementioned behavioral changes can lead to transmission of stress between individuals. In the present study the aim is to investigate the outcomes of the behavioral interaction between stressed and unstressed animals housed together. A total of 28 adult male Wistar rats were used in the study. The animals were randomly allocated to four groups. Two of the groups were exposed to white noise stress in a period of 15days, while the other two groups remained unstressed. One of the stress exposed groups served as the stress control (SC) group and one of the non-stressed groups served as the reference value (RV) group. The remaining two groups were transmission groups. Every two animals of the non-stressed transmission group (TC) have been housed with two other animals of the stress exposed transmission group (TS) during the experimental period. After the stress exposure period, six animals from each group were subjected to behavioral assessment in an elevated plus maze (EPM), and subsequently, their cortisol levels were determined. White noise exposure of animals in the SC group induced a stress response indicated by an 1.8 fold increase of plasma cortisol level compared to the RV group (2.11±0.43 and 1.16±0,02, respectively). The transmission groups (TS and TC) entered the open arms more frequently and spent more time in open arms compared to the RV group. White noise exposure caused a stress response characterized by an elevation of cortisol level in rats. The gradual decrease of cortisol level from the SC towards the RV group may be interpreted as an evidence supporting the hypothesis of stress-transmission between cagemates. The moderate stress levels of the transmission groups, but not low and high levels of the SC and RV groups, decreased the anxiety-like behavior, which indicates an inverted U-shaped relationship between stress levels and anxiolytic effectiveness.

Effects of curcumin on proinflammatory cytokines and tissue injury in the early and late phases of experimental acute pancreatitis.

BACKGROUND & AIMS: Acute pancreatitis (AP) varies from mild to severe necrotizing changes with high mortality. The objective of the current study was to investigate the effects of curcumin on tissue injury and proinflammatory cytokines in the early and late phases of AP. METHODS: AP was induced by sodium taurocholate in rats (n = 140). First group was left untreated. Group II received 100 mg/kg curcumin daily starting 20 days before AP induction. The rats were allocated into 7 sub-groups (n:5) and were sacrificed at 2, 6, 12, 24, 72, 144 and 288 h following the induction of AP. Blood and pancreatic tissue samples were collected for biochemical and histopathologic evaluations and the assessment of protein and mRNA levels, as well. RESULTS: Curcumin decreased total histopathologic scores in comparison with those of the taurocholate group (P < 0.05). Curcumin increased Caspase-3 activity and decreased trypsin activity, while inhibited nuclear factor-κ (NF-κB) at all time points (P < 0.05) and moreover reduced activator protein-1 (AP-1). Curcumin decreased chemokine (except for 288 h), TNF-α (except for 2 and 24 h), IL-6 (except for 2, 6 and 288 h) and iNOS (except for 144 and 288 h) mRNA levels (P < 0.05). Curcumin serum nitric oxide (NO) (except for 144 and 288 h) levels were reduced, as well. CONCLUSIONS: In conclusion, curcumin reduced tissue injury, trypsin activation and inhibited NF-κB and AP-1. However TNF-α, IL-6 and iNOS and NO were not inhibited at all time points. Therefore no direct correlation was detected in the subgroups between tissue injury, proinflammatory cytokines and oxidative enzymes.

Long-term aspirin pretreatment in the prevention of cerulein-induced acute pancreatitis in rats.

AIM: To investigate the effects of long term pretreatment with low-, medium- and high-dose aspirin (acetylsalicylic acid, ASA) on a model of acute pancreatitis (AP) induced in rats. METHODS: Forty male Wistar rats were used. Three experimental groups, each consisting of eight animals, received low- (5 mg/kg per day), medium- (150 mg/kg per day) and high-dose (350 mg/kg per day) ASA in supplemented pellet chow for 100 d. Eight animals, serving as the AP-control group, and another eight, serving as reference value (RV) group, were fed with standard pellet chow for the same period. After pretreatment, AP was induced in the experimental animals by intraperitoneal administration of cerulein (2 × 50 µg/kg), while the RV group received saline in the same way. Twelve hours after the second injection, the animals were sacrificed. Pancreatic tissue and plasma samples were collected. One part of the collected pancreatic tissues was used for histopathological evaluation, and the remaining portion was homogenized. Cytokine levels [tumor necrosis factor, interleukin (IL)-1ß, IL-6], hemogram parameters, biochemical parameters (amylase and lipase), nuclear factor-κB, aspirin triggered lipoxins and parameters related to the antioxidant system (malondialdehyde, nitric oxide, hemeoxygenase-1, catalase and superoxide dismutase) were measured. RESULTS: Cerulein administration induced mild pancreatitis, characterized by interstitial edema (total histopathological score of 5.88 ± 0.44 vs 0.25 ± 0.16, P < 0.001). Subsequent pancreatic tissue damage resulted in an increase in amylase (2829.71 ± 772.48 vs 984.57 ± 49.22 U/L, P = 0.001) and lipase (110.14 ± 75.84 U/L vs 4.71 ± 0.78 U/L, P < 0.001) in plasma, and leucocytes (6.89 ± 0.48 vs 4.36 ± 0.23, P = 0.001) in peripheral blood. Cytokines, IL-1ß (18.81 ± 2.55 pg/µg vs 6.65 ± 0.24 pg/µg, P = 0.002) and IL-6 (14.62 ± 1.98 pg/µg vs 9.09 ± 1.36 pg/µg, P = 0.04) in pancreatic tissue also increased. Aspirin pretreatment reduced the increase in the aforementioned parameters to a certain degree and partially improved the histopathological alterations caused by cerulein. No evidence of side effects related to chronic ASA administration (e.g., inflammation or bleeding) was observed in the gastrointestinal tract in macroscopic and histopathological examination. CONCLUSION: Long term ASA pretreatment could prevent and/or ameliorate certain hematological, serological and histological alterations caused by cerulein-induced AP.

Influence of ram presence (permanent vs. intermittent) on estrus parameters and behaviours in Kivircik ewes.

The present study was undertaken to investigate the effects of type of ram presence (permanent vs. intermittent) on estrus onset, estrus duration and frequency of sexual behaviours in Kivircik ewes. During the breeding season, 20 multiparous Kivircik ewes were divided into two groups of permanent (PR) and intermittent (IR) presence of ram. Estrus was synchronized with fluorgestone acetate intravaginal sponges left for 14 days, plus an injection of 600 IU PMSG at the time of sponge removal. PR ewes introduced with ram immediately after sponge removal and remained with the ram throughout the study (5 days). IR ewes were exposed to ram twice a day, only during the observation periods. Behavioural observations were performed twice a day (at 07:00 a. m. and 07:00 p.m.) for a 2-hour period. Estrus onset was 32.40 +/- 1.60 h for PR group and 27.60 +/- 2.40 h for IR group (p > 0.05). Estrus duration was 15.60 +/- 1.83 h and 34.80 +/- 2.15 h for the same groups, respectively (p < 0.001). Standing was the most frequently displayed behaviour in both groups. IR ewes displayed sexual (p < 0.001), eating (p < 0.001), standing (p < 0.001), walking (p < 0.001), urination (p < 0.001) and defecation (p < 0.05) behaviours much more than the PR ewes. Frequency of each sexual behaviour was higher in IR group compared with PR group throughout the study. Among the proceptive behaviours investigated, head-turning was the most frequently displayed behaviour in both groups. Soliciting, non-firm standing, sniffing scrotum and anogenital sniffing behaviours were also expressed by the ewes considerably. It is concluded that, if the ewes are exposed to ram intermittently, behavioural signs of estrus could be recognized more successfully. Furthermore, the possibility of insemination of estrous ewes becomes much higher by the intermittent presence of ram and thus reproductive performance of the herd could be improved.