Dietary magnesium deficiency impaired intestinal structural integrity in grass carp (Ctenopharyngodon idella)

A new insight on copper: Promotion of collagen synthesis and myofiber growth and development in juvenile grass carp (Ctenopharyngodon idella)

Copper (Cu) is a trace element, essential for fish growth. In the current study, in addition to growth performance, we first explored the effects of Cu on collagen synthesis and myofiber growth and development in juvenile grass carp (Ctenopharyngodon idella). A total of 1080 fish (11.16 ± 0.01 g) were randomly divided into 6 treatments (3 replicates per treatment) to receive five doses of organic Cu, which were Cu citrate (CuCit) at 0.99 (basal diet), 2.19, 4.06, 6.15, and 8.07 mg/kg, and one dose of inorganic Cu (CuSO4·5H2O at 3.15 mg/kg), for 9 weeks. The results showed appropriate Cu level (4.06 mg/kg) enhanced growth performance, improved nutritional Cu status, and downregulated Cu-transporting ATPase 1 mRNA levels in the hepatopancreas, intestine, and muscle of juvenile grass carp. Meanwhile, collagen content in fish muscle was increased after Cu intake, which was probably due to the following pathways: (1) activating CTGF/TGF-β1/Smads signaling pathway to regulate collagen transcription; (2) upregulating of La ribonucleoprotein domain family 6 (LARP6) mRNA levels to regulate translation initiation; (3) increasing proline hydroxylase, lysine hydroxylase, and lysine oxidase activities to regulate posttranslational modifications. In addition, optimal Cu group increased myofiber diameters and the frequency of myofibers with diameter >50 μm, which might be associated with upregulation of cyclin B, cyclin D, cyclin E, proliferating cell nuclear antigen, myogenic determining factor (MyoD), myogenic factor 5, myogenin (MyoG), myogenic regulatory factor 4 and myosin heavy chain (MyHC) and downregulation of myostatin mRNA levels, increasing protein levels of MyoD, MyoG and MyHC in fish muscle. Finally, based on percentage weight gain (PWG), serum ceruloplasmin (Cp) activity and collagen content in fish muscle, Cu requirements were determined as 4.74, 4.37 and 4.62 mg/kg diet (CuCit as Cu source) of juvenile grass carp, respectively. Based on PWG and Cp activity, compared to CuSO4·5H2O, the efficacy of CuCit were 131.80% and 115.38%, respectively. Our findings provide new insights into Cu supplementation to promote muscle growth in fish, and help improve the overall productivity of aquaculture.

BMP-2/TGF-β1 gene insertion into ligament-derived stem cells sheet promotes tendon-bone healing in a mouse

Bone morphogenetic protein-2 (BMP-2) and transforming growth factor-β1 (TGF-β1) reportedly induce the osteogenic and tenogenic differentiation of anterior cruciate ligament (ACL)-derived stem cells (LDSCs), respectively. However, few studies have investigated the effect of BMP-2/TGF-β1 on the differentiation of LDSC. We developed a BMP-2/TGF-β1 gene insertion into an LDSC cell sheet that promotes tendon-bone healing in a mouse ACL reconstruction (ACLR) model. CD34⁺ LDSCs were isolated from human ACL stump tissues, virally transduced to express BMP-2 or TGF-β1, and then embedded within cell sheets. All mice underwent ACLR using an autograft wrapped with a cell sheet and were randomly divided into three groups: BMP-2-, TGF-β1-, and BMP-2/TGF-β1-transduced. At 4 and 8 weeks, tendon-bone healing was evaluated by micro-CT, biomechanical test, and histological analysis. BMP-2 and TGF-β1 promoted the osteogenic and tenogenic differentiation of LDSC in vitro. BMP-2/TGF-β1-transduced LDSC sheet application contributed to early improvement in mean failure load and graft stiffness, accelerated maturation of the tendon-bone junction, and inhibited bone tunnel widening. Furthermore, reduced M1 macrophage infiltration and a higher M2 macrophage percentage were observed in the BMP-2/TGF-β1-transduced LDSC group. This work demonstrated that BMP-2 and TGF-β1 promoted CD34⁺ LDSCs osteogenic and tenogenic differentiation in vitro and in vivo, which accelerated the tendon-bone healing after ACLR using autografts wrapped with cell sheets in a mouse model.

CENTRAL AND PERIPHERAL EFFECT OF MPTP VIA DOSE-DEPENDENT MAGNESIUM MODULATION

Background

Recent studies suggested that MPTP could cause gastrointestinal motility deficits additionally to its nonconclusive and controverted effects on the CNS (behavior and brain oxidative stress) in rats. A possible interaction between MPTP typical impairments and magnesium modulatory potential was previously suggested, as magnesium role was described in neuroprotection, gastrointestinal function, and oxidative stress.

Aim

To investigate the possible modulatory effect of several magnesium intake formulations (via drinking water) in MPTP neurotoxicity and functional gastrointestinal impairment induction.

Materials and Methods

Adult male Wistar rats were subjected to 3-week magnesium intake-controlled diets (magnesium depleted food and magnesium enriched drinking water) previously to acute subcutaneous MPTP treatment (30 mg/ kg body weight). Gastrointestinal motility (one hour stool collection test), and behavioral patterns (Y maze task, elevated plus maze test, open field test, forced swim test) were evaluated. Followingly, brain and bowel samples were collected, and oxidative stress was evaluated (glutathione peroxidase activity, malondial-dehyde concentrations).

Results

MPTP could lead to magnesium intake-dependent constipation-like gastrointestinal motility impairments, anxiety- and depressive-like affective behavior changes, and mild pain tolerance defects. Also, we found similar brain and intestinal patterns in magnesium-dependent oxidative stress.

Conclusion

While the MPTP effects in normal magnesium intake could be regarded as not fully relevant in rat models and limited to the current experimental conditions, the abnormalities observed in the affective behavior, gastrointestinal status, pain tolerance, peripheric and central oxidative status could be indicative of the extent of the systemic effects of MPTP that are not restricted to the CNS level, but also to gastro-intestinal system.

Magnesium in renal fibrosis

PURPOSE

Renal fibrosis (RF) is the main pathological feature of chronic kidney disease (CKD). The main focus of research on treatment for CKD is to develop strategies that delay or prevent RF from progressing to end-stage renal disease (ESRD). Inflammation and oxidative stress occur during all stages of CKD. The magnesium cation (Mg²⁺) can reduce inflammation and oxidative stress, regulate apoptosis, and improve RF, and magnesium-based therapies are promising new treatments that can prevent RF. We reviewed the current evidence on the effects of magnesium in RF and examined the possible mechanism of magnesium in delaying RF.

METHODS

We searched PubMed, Web of Science, and EMBASE for articles on magnesium and fibrosis, with a focus on magnesium and RF.

RESULTS

Inflammation, oxidative stress, and apoptosis are related to the occurrence of CKD. Previous research showed that Mg²⁺ inhibits the differentiation of inflammatory cells, down-regulates the production of inflammatory cytokines, reduces inflammation, and reduces the production of reactive oxygen species (ROS) and oxidative stress. In addition, Mg²⁺ also regulates apoptosis and protects renal tubular function. Magnesium may also regulate TRPM6/7, promote the secretion of klotho protein and improve renal fibrosis. Therefore, Mg²⁺ can protect the kidney from damage and slow down the progression of RF through many molecular and cellular effects. Some of the anti-fibrotic effects of Mg²⁺ may be related to its antagonism of intracellular Ca²⁺.

CONCLUSION

Magnesium may prevent the progression of renal fibrosis and delay CKD by reducing renal inflammation and oxidative stress, and by regulating fibrosis-related signaling pathways and cytokines.

Antioxidant support to ameliorate the oxaliplatin-dependent microglial alteration: morphological and molecular study

Oxaliplatin is a third-generation chemotherapy drug mainly used for colorectal cancer treatment. However, it is also known to trigger neuropathy whose underlying neurobiological mechanisms are still under investigation and currently available treatments show limited efficacy. It is now established that neurons are not the only cell type involved in chronic pain and that glial cells, mainly astrocytes and microglia, are involved in the initiation and maintenance of neuropathy. Among all the pathogenetic factors involved in neuropathic pain, an oxaliplatin-dependent oxidative stress plays a predominant role. In our study, the antioxidant properties of magnesium (Mg), manganese (Mn) and zinc (Zn) salts were evaluated in order to counteract microglial activation induced by oxaliplatin. The antioxidant efficacy of these metals was evaluated by the means of molecular and morphological assays on the BV-2 microglial cell line. Our data clearly show that Mg, Mn and Zn are able to prevent oxaliplatin-dependent microglial alterations by reducing both oxidative and endoplasmic reticulum stress.

Antenatal magnesium sulfate and intestinal morbidities in preterm infants with extremely low gestational age

BACKGROUND

Antenatal magnesium sulfate is widely used as a tocolytic, for maternal seizures, and for seizure prophylaxis in preeclampsia. Recent studies have suggested that antenatal magnesium sulfate use is associated with favorable neurodevelopmental outcomes in preterm infants. However, there are concerns regarding the effects of antenatal magnesium sulfate on neonates, especially regarding gastrointestinal morbidities. This study aims to explore the effects of antenatal magnesium sulfate on intestinal morbidities requiring surgery in preterm infants.

METHODS

This was a retrospective cohort study of 181 preterm infants who were born at less than 28 weeks of gestational age. Subjects were categorized as infants exposed to antenatal magnesium sulfate and those not exposed to antenatal magnesium sulfate.

RESULTS

Antenatal magnesium sulfate was associated with a decreased risk of surgical conditions of the intestine (OR 0.393, 95% CI 0.170-0.905). The multivariate analysis showed that the duration of antenatal magnesium sulfate use was associated with surgical conditions of the intestine (adjusted OR 0.766, 95% CI 0.589-0.997). In the <26 weeks of gestational age subgroup, the use of antenatal magnesium sulfate was significantly associated with decreased intestinal morbidities requiring surgery (adjusted OR 0.234, 95% CI 0.060-0.922).

CONCLUSION

Antenatal magnesium sulfate use appears to have a protective effect on intestinal morbidities requiring surgery in preterm infants in a duration-dependent manner. Association of antenatal magnesium sulfate use and decreased intestinal morbidities requiring surgery was more distinct in preterm infants <26 weeks of gestational age.

Oral exposure of titanium oxide nanoparticles induce ileum physical barrier dysfunction via Th1/Th2 imbalance

In this work, we aimed to evaluate the adverse effects and the mechanism of intestinal barrier caused by titanium dioxide nanoparticles (TiO₂ NPs). Here, the effects of two different dosages (300 and 1200 mg/kg) of TiO₂ NPs on female mice (n = 5) were investigated. After 28-day oral exposure, the results of Ti content were significantly increased in the ileum in comparison with the control. The histopathological structure index of the ileum was significantly changed after TiO₂ NPs exposure; villi height and crypt depth were decreased and increased, respectively. Meanwhile, TiO₂ NPs treatment also significantly altered the transcription levels of genes. First, the GATA-3 and STAT-4 were upregulation and downregulation, respectively. Second, gene expressions of the Zonula Occludens-1, claudin (CLDN)-12, occludin, and myosin light chain kinase were significantly upregulated, while the CLDN-3 was decreased. Finally, the caspase-3, caspase-9, and caspase-12 were upregulated. The results of TUNEL staining indicated apoptosis in the ileum. In general, TiO₂ NPs treatment significantly changed the intestine physical barrier in a dose-dependent manner. The toxicity of TiO₂ NPs could be through the imbalance in the Th1/Th2.