Curcumin's protective role against fluoride-induced bone damage: Implications for pullet pathology and skeletal biomechanics

This study aimed to investigate the effects of dietary fluoride (F) and curcumin (Cur) supplementation on the tibial biomechanical performance, histopathology, and behavior of pullets. Four dietary F levels (0, 400, 800, 1200 mg/kg) supplemented with CUR (0, 200 mg/kg) were used to create 8 experimental groups in Hyline Brown pullets. Behavioral study results showed that supplements of 1200 mg/kg F reduced the percentages of feeding, walking, standing, and preening behaviors while increasing the percentage of lying behavior (P < 0.05). This is associated with F-induced tibial elastic modulus, maximum stress, and stiffness coefficient were reduced and toughness coefficient was increased (P < 0.05). F-induced tibial cortical bone thickened, trabecular bone widened, and excessive accumulation of bone collagen fibers (P < 0.05) in the tibia explained the biomechanical properties reduction in Hyline Brown pullets. Additionally, the loss of antioxidant capacity was mediated by excessive F-accelerated pathological damage to the bone (P < 0.05). Supplementation with 200 mg/kg CUR alleviated abnormal behavior, expansion of the trabecular bone, accumulation of collagen fibers, and loss of antioxidant capacity (P < 0.05). In conclusion, F reduced the antioxidant level of the body, caused tibia histopathological damage, destroyed the tibia biomechanical properties, and caused abnormal behavior of pullets. Supplementation with 200 mg/kg CUR attenuates F-induced oxidative and tibia damage and rectifies abnormal behavioral traits.

Supplementation of the Combination of Quercetin and Vitamin E Alleviates the Effects of Heat Stress on the Uterine Function and Hormone Synthesis in Laying Hens

Chickens are sensitive to heat stress because their capacity to dissipate body heat is low. Hence, in chickens, excessive ambient temperature negatively influences their reproductive performance and health. Heat stress induces inflammation and oxidative stress, thereby rendering many reproductive organs dysfunctional. In this study, we evaluated the effects of the supplementation of dietary quercetin and vitamin E on the uterine function, eggshell quality via estrogen concentration, calcium metabolism, and antioxidant status of the uterus of laying hens under heat stress. The ambient temperature transformation was set at 34 ± 2 °C for 8 h/d (9:00 am-5:00 pm), which was followed by 22 °C to 28 °C for 16 h/d. Throughout the experiment, the relative humidity in the chicken's pen was at 50 to 65%. A total of 400 Tianfu breeder hens (120-days-old) were randomly divided into four dietary experimental groups, including basal diet (Control); basal diet + 0.4 g/kg quercetin; basal diet + 0.2 g/kg vitamin E; and basal diet + the combination of quercetin (0.4 g/kg) and vitamin E (0.2 g/kg). The results show that the combination of quercetin and vitamin E significantly increased the serum alkaline phosphatase levels and the antioxidant status of the uterus (p < 0.05). In addition, the combination of quercetin and vitamin E significantly increased the concentrations of serum estrogen and progesterone, as well as elevated the expression of hypothalamic gonadotropin-releasing hormone-1 and follicular cytochrome P450 family 19 subfamily A member-1 (p < 0.05). We also found that the calcium levels of the serum and uterus were significantly increased by the synergistic effects of quercetin and vitamin E (p < 0.05), and they also increased the expression of Ca2+-ATPase and the mRNA expression of calcium-binding-related genes in the uterus (p < 0.05). These results are consistent with the increased eggshell quality of the laying hens under heat stress. Further, the combination of quercetin and vitamin E significantly increased the uterine morphological characteristics, such as the height of the uterine mucosal fold and the length of the uterine mucosa villus of the heat-stressed laying hens. These results collectively improve the uterine function, serum and uterine calcium concentration, eggshell strength, and eggshell thickness (p < 0.05) in heat-stressed laying hens. Taken together, we demonstrated in the present study that supplementing the combination of dietary quercetin and vitamin E alleviated the effects of heat stress and improved calcium metabolism, hormone synthesis, and uterine function in the heat-stressed laying hens. Thus, the supplementation of the combination of quercetin and vitamin E alleviates oxidative stress in the eggshell gland of heat-stressed laying hens, thereby promoting calcium concentration in the serum and eggshell gland, etc., in laying hens. Hence, the combination of quercetin and vitamin E promotes the reproductive performance of the laying hens under heat stress and can also be used as a potent anti-stressor in laying hens.

Dietary supplementation with selenomethionine enhances antioxidant capacity and selenoprotein gene expression in layer breeder roosters

This study's objective was to investigate the effects of dietary Se (in the form of selenomethionine) on the antioxidant activity and selenoprotein gene expressions in layer breeder roosters. One hundred and eighty, 36-wk-old Jingfen layer breeder roosters were randomly allocated to one of 5 dietary treatments (0, 0.25, 0.5, 1, or 2 mg/kg Se) for 6 wk on a corn-soybean meal-based diet. Antioxidant parameters and selenoprotein gene expressions were assessed at the end of the experiment. The results showed that Se supplementation significantly increased the activity of T-SOD, CAT, GSH-Px, and superoxide anion scavenging ability in plasma (P ≤ 0.05), and activities of T-SOD, CAT, GSH-Px, superoxide anion scavenging ability, and hydroxyl radical scavenging ability in the liver, kidney, and testis (P < 0.05). Moreover, MDA levels were significantly reduced in plasma, liver, kidney, and testis (P < 0.01), compared to the control group. Furthermore, the dietary administration of Se significantly increased TrxR2 and GPx4 mRNA levels in kidney and testis, and ID1 mRNA levels in liver and kidney. Most of the antioxidant parameters and selenoprotein-related gene expressions significantly increased, and MDA significantly decreased at dietary supplementation with 0.5 mg/kg Se. Whereas a higher dose of Se level (1 or 2 mg/kg) inhibited the activities of some of the antioxidant enzymes and selenoprotein-related gene expressions in selected tissues. In conclusion, dietary Se supplementation with 0.5 mg/kg significantly improved roosters’ antioxidant status and selenoprotein-related gene expression in liver, kidney, and testis, while higher doses led to inhibit these; dietary Se might increase reproductive performance by enhancing their antioxidant status in roosters.

Prospects for the Role of Ferroptosis in Fluorosis

As a strong oxidant, fluorine can induce oxidative stress resulting in cellular damage. Ferroptosis is an iron-dependent type of cell death caused by unrestricted lipid peroxidation (LPO) and subsequent plasma membrane rupture. This article indicated a relationship between fluorosis and ferroptosis. Evidence of the depletion of glutathione (GSH) and increased oxidized GSH can be found in a variety of organisms in high fluorine environments. Studies have shown that high fluoride levels can reduce the antioxidant capacity of antioxidant enzymes, while increasing the contents of reactive oxygen species (ROS) and malondialdehyde (MDA), resulting in oxidative stress and fluoride-induced oxidative stress, which are related to iron metabolism disorders. Excessive fluorine causes insufficient GSH, glutathione peroxidase (GSH-Px) inhibition, and oxidative stress, resulting in ferroptosis, which may play an important role in the occurrence and development of fluorosis.

Recent advances in cellular effects of fluoride: an update on its signalling pathway and targeted therapeutic approaches

Fluoride is a natural element essential in minute quantities in human's to maintain dental and skeletal health. However, the disease fluorosis manifests itself due to excessive fluoride intake mostly through drinking water and sometimes through food. At the cellular energetics level, fluoride is a known inhibitor of glycolysis. At the tissue level, the effect of fluoride has been more pronounced in the musculoskeletal systems due to its ability to retain fluoride. Fluoride alters dentinogenesis, thereby affecting the tooth enamel formation. In bones, fluoride alters the osteogenesis by replacing calcium, thus resulting in bone deformities. In skeletal muscles, high concentration and long term exposure to fluoride causes loss of muscle proteins leading to atrophy. Although fluorosis is quite a familiar problem, the exact molecular pathway is not yet clear. Extensive research on the effects of fluoride on various organs and its toxicity was reported. Indeed, it is clear that high and chronic exposure to fluoride causes cellular apoptosis. Accordingly, in this review, we have highlighted fluoride-mediated apoptosis via two vital pathways, mitochondrial-mediated and endoplasmic reticulum stress pathways. This review also elaborates on new cellular energetic, apoptotic pathways and therapeutic strategies targeted to treat fluorosis.

Sodium Fluoride In Vitro Treatment Affects the Expression of Gonadotropin and Steroid Hormone Receptors in Chicken Embryonic Gonads

Simple Summary

Effects of in vitro sodium fluoride (NaF) treatment on the mRNA expression of luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), estrogen receptors (ESR1 and ESR2), progesterone receptor (PGR), and the immunolocalization of PGRs were examined in gonads of 14-day-old chicken embryos. In the ovary, the NaF treatment significantly increased mRNA levels of all investigated receptors. In the testes, the lowest applied dose of NaF (1.7 mM) significantly decreased the expression of FSHR, ESR1, ESR2, and PGR. Alternatively, the higher NaF dose (7.1 mM) elevated PGR mRNA level in the male gonad. Immunohistochemical analysis revealed that the NaF exposure increased PGR expression in the ovarian cortex, while it decreased its expression in the testes. Collectively, these data indicate that: (i) NaF may disturb the chicken embryonic development, and (ii) different mechanisms of this toxicant action exist within the female and male gonads.

Abstract

Sodium fluoride (NaF), in addition to preventing dental decay may negatively affect the body. The aim of this study was to examine the effect of a 6 h in vitro treatment of gonads isolated from 14-day-old chicken embryos with NaF at doses of 1.7 (D1), 3.5 (D2), 7.1 (D3), and 14.2 mM (D4). The mRNA expression of luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), estrogen receptors (ESR1 and ESR2), progesterone receptor (PGR), and the immunolocalization of progesterone receptors were examined in the tissue. In the ovary, the expression of FSHR and LHR increased following the NaF treatment. In the case of FSHR the highest stimulatory effect was noticed in the D2 group, while the expression of LHR increased in a dose-dependent manner. A gradual increase in ESR1 and PGR mRNA levels was also observed in the ovary following the NaF treatment, but only up to the D3 dose of NaF. The highest ESR2 level was also found in the D3 group. In the testes, the lowest dose of NaF significantly decreased the expression of FSHR, ESR1, ESR2, and PGR. On the other hand, an increase in PGR expression was observed in the D3 group. The expression of LHR in the testes was not affected by the NaF treatment. Immunohistochemical analysis showed that NaF exposure increased progesterone receptor expression in the ovarian cortex, while it decreased its expression in the testes. These results reveal that NaF may disturb the chicken embryonic development and different mechanisms of this toxicant action exist within the females and males.

Excess dietary fluoride affects laying performance, egg quality, tissue retention, serum biochemical indices, and reproductive hormones of laying hens

The present study aimed to evaluate the effects of excess dietary fluoride (F) on laying performance, egg quality, tissue retention, serum biochemical indices, and serum reproductive hormones of laying hens. A total of 384 Hy-Line Gray hens, 37 wk old, were treated with sodium fluoride added to a corn-soybean meal basal diet at 0, 400, 800, and 1200 mg fluorine/kg feed. The results showed that dietary F levels at 800 and 1200 mg/kg markedly decreased ADFI, laying rate, average egg weight, and increased feed conversion ratio (FCR) (P < 0.05). Dietary F levels at 800 and 1200 mg/kg dramatically decreased the egg quality of albumen height, yolk color, eggshell strength, and eggshell thickness, and on the 49th D, 400 mg/kg F group significantly decreased the eggshell strength, compared to those of control group. Fluoride residues in tissues of hens were increased significantly with the increase of dietary F supplemental levels (P < 0.05). Fluoride concentrations were generally high in feces, eggshell, tibia, kidney, and ovary, and the highest in feces, following with eggshell and tibia, lower in kidney and ovary, and the lowest in serum. Serum uric acid levels and alanine aminotransferase activity increased significantly (P < 0.05), and glucose, triglycerides, and phosphorus decreased significantly (P < 0.05) in response to dietary F concentration, compared to those of the control group, respectively. Dietary F supplementation at 1200 mg/kg significantly decreased (P < 0.05) the estrogen concentrations in serum, compared to those of the control group. Concentrations of progesterone in the fluoride-treated groups were significantly (P < 0.05) decreased relative to those of the control group. In conclusion, these results indicated that the excessive ingestion of F has had a detrimental effect on egg laying rate and quality of eggs by damaging the function of the liver, kidney, and ovary of laying hens.

Vitamin C Attenuates Sodium Fluoride-Induced Mitochondrial Oxidative Stress and Apoptosis via Sirt1-SOD2 Pathway in F9 Cells

Increasing evidence has suggested an important role played by reactive oxygen species (ROS) in the pathogenesis of fluorosis. Accumulating evidence demonstrates that vitamin C administration ameliorate sodium fluoride (NaF)-induced oxidative stress. However, the potentially beneficial effects of vitamin C against NaF-induced cytotoxicity and the underlying molecular mechanisms of this protection are not fully understood. Here, we found that NaF stimulated cytotoxicity, increased mitochondrial reactive oxygen species (mROS) production, and induced apoptosis in F9 embryonic carcinoma cells. Consistent with this finding, NaF exposure was associated with decreased Sirtuin 1 (Sirt1) protein expression, thus promoted the acetylation of manganese superoxide dismutase (SOD2), a key enzyme involved in regulating mROS production. However, all NaF-induced mitochondrial oxidative injuries were efficiently ameliorated by overexpression of Sirt1 or incubation with Mito-TEMPO (a SOD2 mimetic). Moreover, pretreatment with vitamin C enhanced the expression of Sirt1 and decreased NaF-induced mitochondrial oxidative stress and apoptosis. Knockdown of Sirt1 blocked the vitamin C-mediated reduction in mROS and apoptosis via inhibiting Sirt1-SOD2 signaling. Importantly, sodium-dependent vitamin C transporter 2 (SVCT-2) siRNA was found to partially block the ability of vitamin C to promote Sirt1/SOD2 signaling. In summary, our data indicate that Sirt1 plays a pivotal role in the ability of vitamin C to stimulate SOD2 activity and attenuate mitochondrial oxidative stress, which partially through vitamin C receptor in NaF-induced F9 cells injury.