Effects of chromium and copper depletion on lymphocyte reactivity to mitogens in diabetes-prone BHE/cdb rats

The roles of essential trace elements in T cell biology

T cells are crucial for adaptive immunity to regulate proper immune response and immune homeostasis. T cell development occurs in the thymus and mainly differentiates into CD4+ and CD8+ T cell subsets. Upon stimulation, naive T cells differentiate into distinct CD4+ helper and CD8+ cytotoxic T cells, which mediate immunity homeostasis and defend against pathogens or tumours. Trace elements are minimal yet essential components of human body that cannot be overlooked, and they participate in enzyme activation, DNA synthesis, antioxidant defence, hormone production, etc. Moreover, trace elements are particularly involved in immune regulations. Here, we have summarized the roles of eight essential trace elements (iron, zinc, selenium, copper, iodine, chromium, molybdenum, cobalt) in T cell development, activation and differentiation, and immune response, which provides significant insights into developing novel approaches to modulate immunoregulation and immunotherapy.

Supplementation With Vitamin E, Zinc, Selenium, and Copper Re-Establishes T-Cell Function and Improves Motor Recovery in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) causes a dysfunction of sympathetic nervous system innervation that affects the immune system, leading to immunosuppression syndrome (ISS) and contributing to patient degeneration and increased risk of several infections. A possible therapeutic strategy that could avoid further patient deterioration is the supplementation with Vitamin E or trace elements, such as Zinc, Selenium, and Copper, which individually promotes T-cell differentiation and proliferative responses. For this reason, the aim of the present study was to evaluate whether Vitamin E, Zinc, Selenium, and Copper supplementation preserves the number of T-lymphocytes and improves their proliferative function after traumatic SCI. Sprague–Dawley female rats were subjected to moderate SCI and then randomly allocated into three groups: (1) SCI + supplements; (2) SCI + vehicle (olive oil and phosphate-buffered saline); and (3) sham-operated rats. In all rats, the intervention was initiated 15 min after SCI and then administered daily until the end of study. Locomotor recovery was assessed at 7 and 15 days after SCI. At 15 days after supplementation, the quantification of the number of T-cells and its proliferation function were examined. Our results showed that the SCI + supplements group presented a significant improvement in motor recovery at 7 and 15 days after SCI. In addition, this group showed a better T-cell number and proliferation rate than that observed in the group with SCI + vehicle. Our findings suggest that Vitamin E, Zinc, Selenium, and Copper supplementation could be part of a therapy for patients suffering from acute SCI, helping to preserve T-cell function, avoiding complications, and promoting a better motor recovery. All procedures were approved by the Animal Bioethics and Welfare Committee (Approval No. 201870; CSNBTBIBAJ 090812960).

Effects of supplemental chromium on interferon-gamma (IFN-gamma) mRNA expression in response to Newcastle disease vaccine in broiler chicken

We report the effects of supplemental chromium (Cr) on interferon-gamma (IFN-gamma) expression in response to Newcastle disease virus (NDV) vaccine in broiler chicken. Two hundred and eighty day old straight run broiler chicks were randomly selected and allocated at random to one of the seven treatment groups replicated four times having 10 chicks in each replication. Treatment 1 (C) was a standard control diet in which no Cr was offered to birds either through feed or drinking water. In treatments 2-4 (F500, F1000 and F1500), Cr in the form of chromium picolinate (CrPic) was added at rates of 500, 1000 and 1500 ppb in diets, respectively. In treatments 5-7 (W250, W500 and W750), Cr as added to the drinking water at rates of 250, 500 and 750 ppb, respectively. The feeding was continued from 1 to 49 d of age. On 49 d, three birds from each replicate, i.e. 12 birds/treatment were inoculated intramuscularly with R(2)B strain of NDV. Twelve unvaccinated birds along with 12 vaccinated birds from each treatment (four birds each day) were then sacrificed on 1, 3 and 7 days post-immunization to study the IFN-gamma expression using quantitative real time PCR. Following the immunization, the IFN-gamma mRNA expression in spleen was significantly (P<0.01) either up-regulated or down-regulated at day 1 and day 3 post-stimulation. Whereas, IFN-gamma mRNA expression reached basal level in all the vaccinated groups at day 7 post-stimulation. IFN-gamma mRNA expression on day 1 was approximately two and four times higher than the control (C) levels in F500 and W500 groups, respectively. On 3 day post-immunization, IFN-gamma mRNA expression in spleen was about 40 and 27 times higher than controls (C) in F500 and W500 groups, respectively. Other groups (F1000, F1500, W250 and W750) showed down-regulation of IFN-gamma mRNA expression. The results suggested that the dosage of chromium modulates the expression of IFN-gamma and route has effect on the onset and duration of the response. Thus, the supplementation of chromium at appropriate dose might be helpful to enhance the IFN-gamma mRNA expression in response to NDV.

Improvement of induction method of non-alcoholic fatty liver model in rats

AIM: To establish a rapid rat model of non-alcoholic fatty liver.

METHODS: Twenty-four male Sprague Dawley rats were averagely and randomly divide into group A, B and C, fed with normal diet, routine high-fat diet and routine high-fat diet plus sucrose, propylthiouracil, and sodium cholate, respectively. The general conditions and weight changes were dynamically observed for 5 wk, and then all the rats were killed. The pathological changes of liver tissues were observed by HE staining, and Sudan IV staining and electron microscopy were used to investigate the presence status of cytoplasmic lipid droplets in liver cells. The following indexes were compared between the three groups, including serum levels of triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and superoxide dismutase (SOD), and tissue contents of TG and TC.

RESULTS: Starting from the fourth week, the weights of rats were significantly decreased in group A and C as compared with those in group B (249.63 ± 34.25, 241.88 ± 20.75 vs 275.38 ± 6.59, P < 0.05), but there was no marked difference between group A and C (P > 0.05). In the 5^th week, light microscopy showed a great number of fatty vacuoles in liver cells, and electron microscopy confirmed the presence of abundant lipid droplets. Different degrees of hepatic fatty degeneration (+~+++) was observed in group C (H = 13.36, P = 0.0003), but not in group A and B. The serum levels of TG, TC, ALT and MDA were markedly higher in group C than those in group A and B (TG: 1.28 ± 0.61 mmol/L vs 0.72 ± 0.12, 0.76 ± 0.04 mmol/L; TC: 12.78 ± 1.47 mmol/L vs 1.71 ± 0.03, 2.31 ± 0.49 mmol/L; ALT: 1518.64 ± 186.04 nkat/L vs 1181.57 ± 37.84, 1262.92 ± 159.20 nkat/L; MDA: 13.40 ± 4.24 μmol/L vs 5.89 ± 1.05, 7.23 ± 1.15 μmol/L; all P < 0.05), but the activity of SOD was lower in group C (5.21 ± 0.81 nkat/mL vs 11.91 ± 2.69, 11.19 ± 0.78 nkat/mL, P < 0.05). There were no notable differences between group A and B (P > 0.05). The tissue contents of TG and TC were dramatically higher both in group B and C than those in group A (TG: 2.14 ± 0.26, 5.83 ± 1.42 mmol/L vs 1.20 ± 0.16 mmol/L, P < 0.05; TC: 3.19 ± 0.23, 9.63 ± 1.12 mmol/L vs 2.13 ± 0.16 mmol/L, P < 0.05), and there was also statistical difference between group B and C (P < 0.05).

CONCLUSION: The rat model of non-alcoholic fatty liver can be successfully established within 5 wk by the improved method, which needs less time and cost during the construction, and basically simulating the occurrence and progression of non-alcoholic fatty liver in human beings.