Zinc improves the immune function and the proliferation of lymphocytes in Cadmium-treated rats

The Cd/Zn Axis: Emerging Concepts in Cellular Fate and Cytotoxicity

Cadmium (Cd) is a toxic and carcinogenic substance that is present in the natural environment. The underlying biomolecular mechanisms of Cd toxicity are not completely understood, and it continues to be a significant research target due to its impact on public health. The primary routes of exposure are through ingestion of contaminated food and water and inhalation. Cd's long biological half-life of 10-30 years allows it to accumulate in the body, leading to organ dysfunction notably in the kidney, liver, bone, and lungs. Cd has similar biochemical characteristics to Zinc (Zn). It shares the import transporters, ZIP8 and ZIP14, to enter the cells. This competitive behavior can be observed in multiple instances throughout the progression of Cd toxicity. Future studies on the biochemical interactions of Cd and Zn will elucidate the potential protective effects of Zn supplementation in reducing the effects of Cd toxicity. In addition, research can be focused on discovering key proteins and effective pathways for Cd elimination that confer fewer adverse effects than current antioxidant therapies.

Effect of zinc supplementation on immunotoxicity induced by subchronic oral exposure to glyphosate-based herbicide (GOBARA®) in Wistar rats

OBJECTIVES

To evaluate the effect of zinc supplementation on immunotoxicity induced by subchronic oral exposure to glyphosate-based herbicide (GBH).

METHODS

Sixty adult male Wistar rats randomly divided equally into six groups were exposed to GBH by gavage daily for 16 weeks with or without zinc pretreatment. Group DW rats received distilled water (2 mL/kg), group Z rats received zinc (50 mg/kg), and group G1 and G2 rats received 187.5 and 375 mg/kg GBH, respectively. Group ZG1 and ZG2 rats were pretreated with 50 mg/kg zinc before exposure to 187.5 and 375 mg/kg GBH, respectively. Tumor necrosis factor alpha (TNF-α) and immunoglobulin (IgG, IgM, IgE) levels were measured by enzyme-linked immunosorbent assay. Spleen, submandibular lymph node, and thymus samples were processed for histopathology.

RESULTS

Exposure to GBH (G1 and G2) significantly increased serum TNF-α concentrations and significantly decreased serum IgG and IgM concentrations compared with the control levels. Moderate-to-severe lymphocyte depletion occurred in the spleen, lymph nodes, and thymus in the GBH-exposed groups. Zinc supplementation mitigated the immunotoxic effects of GBH exposure.

CONCLUSIONS

GBH exposure increased pro-inflammatory cytokine responses, decreased immunoglobulin production, and depleted lymphocytes in lymphoid organs in rats, but zinc supplementation mitigated this immunotoxicity.

Smoking-Related DNA Methylation is Differentially Associated with Cadmium Concentration in Blood

Tobacco smoking, a risk factor for several human diseases, can lead to alterations in DNA methylation. Smoking is a key source of cadmium exposure; however, there are limited studies examining DNA methylation alterations following smoking-related cadmium exposure. To identify such cadmium exposure-related DNA methylation, we performed genome-wide DNA methylation profiling using DNA samples from 50 smokers and 50 non-smokers. We found that a total of 136 CpG sites (including 70 unique genes) were significantly differentially methylated in smokers as compared to that in non-smokers. The CpG site cg05575921 in the AHRR gene was hypomethylated (Δ ß >  - 0.2) in smokers, which was in accordance with previous studies. The rs951295 (within RNA gene LOC105370802) and cg00587941 sites were under-methylated by > 15% in smokers, whereas cg11314779 (within CELF6) and cg02126896 were over-methylated by ≥ 15%. We analyzed the association between blood cadmium concentration and DNA methylation level for 50 smokers and 50 non-smokers. DNA methylation rates of 307 CpG sites (including 207 unique genes) were significantly correlated to blood cadmium concentration (linear regression P value < 0.001). The four significant loci (cg05575921 and cg23576855 in AHRR, cg03636183 in F2RL3, and cg21566642) were under-methylated by > 10% in smokers compared to that in non-smokers. In conclusion, our study demonstrated that DNA methylation levels of rs951295, cg00587941, cg11314779, and cg02126896 sites may be new putative indicators of smoking status. Furthermore, we showed that these four loci may be differentially methylated by cadmium exposure due to smoking.

Prenatal and postnatal cadmium exposure and cellular immune responses among pre-school children

BACKGROUND

Experimental studies have demonstrated that cadmium exposure induces alterations on immune function, but epidemiological evidence is lacking.

OBJECTIVE

To examine the associations between prenatal and postnatal cadmium exposure and cellular immune responses among pre-school children.

METHODS

Pre-school aged children (n = 407) were followed from a prospective birth cohort study in Wuhan, China. Maternal urinary and children's plasma cadmium concentrations were measured as biomarkers of prenatal and postnatal cadmium exposure, respectively. Children's cellular immune responses were assessed by peripheral blood T lymphocyte subsets and plasma cytokines. Multivariable adjusted models were applied to estimate the associations of prenatal and postnatal cadmium exposure with T lymphocyte subsets and cytokines, and the effect modification by child gender were also examined.

RESULTS

Maternal urinary cadmium was associated with reduced absolute counts of CD3⁺CD4⁺ cells (-12.45%; 95% CI: -23.74%, 0.40% for the highest vs. lowest quartile; p for trend = 0.045). Inverse associations of maternal urinary cadmium with %CD3⁺CD4⁺ cells and CD4⁺/CD8⁺ ratio were only observed among females (both p-interaction < 0.050); whereas an inverse association with absolute counts of CD3⁺CD8⁺ cells was only observed among males (p-interaction = 0.057). Positive associations of maternal urinary cadmium with %CD3⁺CD4⁺ cells, interleukin-4 (IL-4), and IL-6 were only observed among females, although there were no significant interactions. We observed no clear associations of children's plasma cadmium with T lymphocyte subsets and cytokines.

CONCLUSION

Prenatal but not postnatal cadmium exposure was associated with sex-specific alterations on children's cellular immune responses.

Morphological changes in spleen after dietary zinc deficiency and supplementation in Wistar rats

BACKGROUND

Study was conducted to determine the effect of dietary zinc deficiency and supplementation on the spleen morphology.

METHODS

Pre-pubertal Wistar rats (40-50 g) were divided into two groups with 6 sub-groups each viz. zinc control (ZC, 100 μg/g zinc diet), pair fed (PF, 100 μg/g zinc diet), zinc deficient (ZD, <1 μg/g zinc diet, zinc supplementation control (ZCS), zinc supplementation pair-fed (PFS) and zinc supplementation deficient (ZDS, 100 μg/g zinc control diet). Experiments were set for 2- and 4-weeks followed by 4 weeks of zinc supplementation.

RESULTS

In the present study body weight and BMI decreased significantly along with incidence of splenomegaly as typified by the increased splenic index in deficient groups compared with that of respective control groups. Histopathological changes such as disorganization of red pulp, several infiltered lymphocytes, vacuolization, loss of cellularity, karyolysis, dissolution of matrix, indistinct differentiation between red and white pulp were evident in spleen of 2ZD and 4ZD group animals. Degeneration was more severe after 4 weeks of zinc deficiency as giant cells formation and hypertrophy were also evident.

CONCLUSION

The findings revealed that zinc deficiency causes growth retardation and splenomegaly. Degenerative and atrophic changes in rat spleen suggest reduced cellular defense potential which will have a direct effect on immunity. Zinc supplementation may prove to be beneficial as there were varying degrees of cellular recovery after cessation of zinc deficiency.

Potential effects of the combination of nicotinamide, vitamin B2 and vitamin C on oxidative-mediated hepatotoxicity induced by thioacetamide

Background

The liver disease is one of the most important traditional public health problems in Egypt. Oxidative stress is attributed to such pathological condition that further contributes to the initiation and progression of liver injury. In the present study, we have investigated if the strong antioxidant power of Nicotinamide (NA), Vitamin B2 (VB2), and Vitamin C (VC) can ameliorate TAA-induced oxidative stress-mediated liver injury in the rats.

Methods

Thirty-six albino rats were divided into six groups: Control group; TAA group (IP injection with TAA at a dosage of 200 mg/Kg three times a week for two months); TAA + NA group (rats administered with NA at a dosage of 200 mg/kg daily besides TAA as in the control); TAA + VB2 group (rats administered with vitamin B2 at a dosage of 30 mg/kg daily besides injection with TAA); TAA + VC group (rats administered with vitamin C at a dosage of 200 mg/kg daily along with injection of TAA). TAA + NA + VB + VC group (rats administered the with the three vitamins daily in TAA pre-injected at the respective doses described above).

Results

Treatment of rats with TAA led to a significant elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total bilirubin, cholesterol, triglycerides, low-density lipoprotein (LDL) and tumor necrosis factor-alpha (TNF-α) in the serum samples. Moreover, malondialdehyde (MDA), hydroxyproline and nitic oxide (NO) were also significantly increased in the TAA-treated rats, while reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were significantly compromised in the hepatic samples. Rats administered with NA, VB2, and VC as individually or in combination ameliorated the deleterious effects of TAA that was confirmed by histopathology. However, the combination of the three vitamins was found more effective as compared to each of the vitamins.

Conclusion

Our work demonstrates that NA, VB2, and VC cross-talk with each other that act as a more potent biochemical chain of antioxidant defense against TAA-induced toxicities in vivo.

Anti-inflammatory properties of a wound dressing combination of zinc oxide and turmeric extract

Aim:

The aim of this study was to determine the effect of a wound dressing consisting of a zinc oxide with turmeric extract combination as an anti-inflammatory on the healing process through the expression of MAC387 and cyclooxygenase-2 (COX-2).

Materials and Methods:

Forty Wistar rats were divided into four control and four treatment groups (n=5). On day 1, a 6 mm×6 mm square of skin in the area of the vertebralis thoracis was excised from all subjects. The wound was then dressed with a combination of zinc oxide and turmeric extract for the treatment groups, while the control groups were left undressed. Both the control and treatment groups were then sequentially sacrificed on days 3, 5, 7, and 14 to obtain subepithelial excision samples. These samples subsequently underwent immunohistochemistry examination through the expression of MAC387 and COX-2 to ascertain the anti-inflammatory reaction to the wound healing process.

Results:

The highest expression of MAC387 was found in the treatment group to which a dressing of zinc oxide with turmeric extract had been applied on the day 5 before slowly reducing on days 7 and 14. MAC387 peaked in the undressed control group on day 14. The COX-2 expression results in control groups showed their higher expression on day 3, increased up to day 5, began to decline on day 7 before, and finally, decreasing on day 14. This result was different to those treatment groups which presented a high COX-2 expression on day 3, before gradually decreasing between days 5 and 7 and reaching its lowest point on day 14.

Conclusion:

A wound dressing consisting of a combination of zinc oxide and turmeric extract has been proven effective as an anti-inflammatory in the healing process.

Can zinc supplementation ameliorate cadmium-induced alterations in the bioelement content in rabbits?

The study was designed to investigate the influence of zinc (Zn) supplementation on cadmium-induced alterations in zinc, copper (Cu), and magnesium (Mg) status in rabbits. For this purpose, the concentrations of cadmium (Cd), Zn, Cu, and Mg were estimated in the blood, liver, kidney, and bone. The rabbits were divided in a control group, a Cd group-animals intoxicated orally with Cd (10 mg kg-1 bw, as aqueous solution of Cd-chloride), and a Cd+Zn group-animals intoxicated with the same dose of Cd and co-treated with Zn (20 mg kg-1 bw, as aqueous solution of Zn-sulphate). Solutions were administered orally, every day for 28 days. Sample mineralisation was performed with concentrated nitric acid (HNO3) and perchloric acid (HClO4) (4:1) and metal concentrations were determined by atomic absorption spectrophotometry (AAS). Zinc supplementation improved some of Cd-induced disturbances in bioelement levels in the investigated tissues. Beneficial effects of Zn on Zn and Cu levels were observed in blood, as well as on the Cu kidney level. The calculated values for Cu/Zn, Mg/Zn, and Mg/Cu ratios in blood suggest that Zn co-treatment reduces Cd-induced changes in bioelement ratios in blood.

Regulatory effects of zinc on cadmium-induced cytotoxicity in chronic inflammation

OBJECTIVES

Zinc (Zn) has major effects on immune system activation while Cadmium (Cd) has anti-inflammatory and anti-proliferative effects in several chronic inflammatory contexts. The aim of this work was to investigate by which mechanisms Zn could compete with Cd and eventually counteract its deleterious effects. Rheumatoid arthritis (RA) synoviocytes exposed to cytokines were used as a model of chronic inflammation; osteoarthritis (OA) synoviocytes were used as control.

METHODS

Cell/medium fractionation constants were analyzed for different metals by inductively-coupled-plasma mass-spectrometry by comparison to the 70Zn spike. Interleukin-17 (IL-17) and tumor necrosis factor-alpha (TNF-α) were used to mimic inflammation. Gene expression of ZIP-8 importer, metallothioneins-1 (MT-1s) and the ratio between metalloprotease-3 and the tissue inhibitor of metalloproteinases (MMP-3)/TIMP-1) were evaluated after pre-exposure to cytokines and Cd, with or without the addition of exogenous Zn (0.9 ppm). Cell viability was measured by neutral red assay and IL-6 production by ELISA.

RESULTS

Synoviocytes selectively absorbed and retained Cd in comparison to Zn. Metal import increased with IL-17/TNF-α exposure, through the enhanced ZIP-8 expression. Zn did not modify ZIP-8 expression, while Cd reduced it (p<0.05). Zn induced a reduction of Cd-induced MT-1s expression, in particular of MT-1X (3-fold), and subsequently the final intra-cellular content of Cd. By reducing Cd accumulation in cells, Zn reversed Cd anti-proliferative and anti-inflammatory effects but preserved the low MMP-3/TIMP-1 ratio induced by Cd, which was enhanced by inflammatory conditions.

CONCLUSION

Zinc counteracts the deleterious effect of Cd by reducing its import and accumulation in the cell, without the reactivation of destructive pathways such as MMPs.

In vivo assessment of newly synthesized achiral copper(ii) and zinc(ii) complexes of a benzimidazole derived scaffold as a potential analgesic, antipyretic and anti-inflammatory

Two new complexes of copper(ii) and zinc(ii) were synthesized and characterized using various spectroscopic techniques. The newly synthesized compounds were screened for analgesic, antipyretic and anti-inflammatory activities.