Inhibitory effect of Athelia rolfsii exopolysaccharides on organ damage in lead-exposed Kunming strain mice

The Impact of Chemokine-Like Receptor 1 Gene Knockout on Lipopolysaccharide-Induced Epididymo-Orchitis in Mice

This comprehensive study delved into the pivotal function of chemokine-like receptor 1 (CMKLR1) in lipopolysaccharide (LPS)-triggered epididymo-orchitis in mice. Upon LPS exposure, wild-type (WT) mice exhibited marked elevations in serum pro-inflammatory markers, including G-CSF, IL-6, and RANTES, along with heightened levels of TNF-α and IL-6 in testicular and epididymal tissues, which accompanied by pronounced structural damage within the testicular tissue and a concurrent decline in serum testosterone, estradiol (E2) levels, and testicular steroid synthetase expression. Remarkably, Cmklr1 gene ablation intensified the pro-inflammatory response in the serum (especially IFN-γ), testes, and epididymis of epididymo-orchitis models. Furthermore, Cmklr1 deficiency uniquely induced structural alterations within the epididymis, which is absent in the WT model. This genetic manipulation also exacerbated the decline in serum testosterone and E2 levels and testicular steroid synthase activity. While chemerin levels were significantly diminished in WT epididymo-orchitis models, Cmklr1 knockout had no discernible effect on chemerin expression in the model. In addition, a noteworthy observation was the elevation of the serum low density lipoprotein/high density lipoprotein (LDL/HDL) ratio in Cmklr1-deficient mice. Collectively, these findings underscore that the lack of chemerin/CMKLR1 signaling axis could potentially worsen the symptoms during LPS-induced epididymo-orchitis, highlighting its potential as a therapeutic target in related pathologies.

In silico prediction aided preparation of antioxidant soybean peptides by enzymatic hydrolysis for ameliorating lead exposure-induced toxicity

Food derived bioactive peptides are prominent dietary supplements to protect against oxidative stress induced by lead (Pb) exposure. This study aimed to develop a new strategy for rapid preparation of highly active antioxidant soybean polypeptides (ASPs) against Pb toxicity. In silico enzymatic hydrolysis simulation and antioxidant activity prediction showed that pepsin, chymotrypsin and bromelain can produce peptides with the highest activity. The preparation process was then optimized, and the obtained ASP showed good antioxidant and metal-chelating activities in vitro. An in vivo study showed that ASP exerted prominent protective effects against Pb-induced cognitive impairment and tissue damage in mice by reducing Pb deposition and enhancing the antioxidant capacity in tissues and was superior to Vc, DMSA or their combination in some aspects. ASP composition analysis demonstrated that its prominent antioxidant activity might be attributed to the high proportion of amino acid residues E, L, P and V in the peptide sequence and L, V and A at the C- and N-termini. In conclusion, in silico prediction could facilitate the preparation of ASP. And the ASP prepared with the new strategy exerted prominent protective effects against Pb toxicity.

Intervention effect of Lycium barbarum polysaccharide on lead-induced kidney injury mice and its mechanism: A study based on the PI3K/Akt/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional medicinal application of Lycium barbarum is centered on the improvement of eyesight, as well as the nourishment of liver and kidney functions. Lycium barbarum polysaccharide (LBP), serving as the principal active constituent of Lycium barbarum, has been identified as the main contributor to these beneficial effects. Previous studies have indicated that Lycium barbarum polysaccharide exhibits a renoprotective effect against lead-induced injury, but its mechanism and efficacy remain unclear.

AIM OF THE STUDY

The objective of this study was to examine the effectiveness of LBP in preventing lead-induced renal injury and investigate both the toxic mechanism of lead-induced renal injury and the efficacy mechanism of LBP against it, with a focus on the PI3K/AKT/mTOR signaling pathway.

MATERIALS AND METHODS

The drug effect and mechanism of LBP on lead-induced kidney injury were investigated by administering positive drugs and LBP to mice with established lead-induced kidney injury.

RESULTS

The renal function of mice with lead-induced renal injury was significantly restored, renal tissue lesions and renal mitochondrial damage were delayed, a disorder of hematological parameters induced by lead was improved, the increase of lead-induced renal index was reduced, and the body weight of mice with lead-induced renal injury was increased by the LBP intervention, as revealed by the results of pharmacodynamic experiments. Based on PI3K /AKT /mTOR signaling pathway, the toxic mechanism of lead-induced kidney injury and the pharmacodynamic mechanism of LBP against lead-induced kidney injury were studied. The results showed that lead could activate the TLR4 receptor, and then activate PI3K /AKT /mTOR signaling pathway, inhibit autophagy of kidney tissue cells, and enhance apoptosis of kidney tissue cells to induce kidney injury; LBP inhibits the activation of TLR4 receptor, which in turn inhibits the PI3K/AKT/mTOR signaling pathway, enhances the autophagy of kidney tissue cells, reduces the apoptosis of kidney tissues, and delays lead-induced kidney injury.

Athelia rolfsii Exopolysaccharide Protection Against Kidney Injury in Lead-Exposed Mice via Nrf2 Signaling Pathway

This study aimed to explore protective efficacy of Athelia rolfsii exopolysaccharides (AEPS) to mice kidney against lead-exposed injury with a focus on the role of nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway. Lead accumulation in the kidney induces oxidative stress which causes low antioxidant activity, abnormal pathological changes, and apoptosis. Here, the changes in lead levels in the kidney and whole blood proved that AEPS inhibited lead accumulation. It might be related to AEPS enhancing glutathione (GSH) levels and glutathione-s-transferase (GST) activities, as well as the protein abundances of multidrug resistance-associated protein 1 (MRP1) and multidrug resistance-associated protein 2 (MRP2). Moreover, AEPS increased antioxidant activity by upregulating superoxide dismutase (SOD), catalase (CAT) activities, downregulating malondialdehyde (MDA) levels. It also restored kidney function by decreasing blood urea nitrogen (BUN) and creatinine (CRE) levels in the serum. Histopathologic analysis showed that AEPS alleviated the kidney injury induced by lead, too. AEPS also showed anti-apoptosis effect by downregulating caspase-3 and bax expression and upregulating bcl-2 expression. Importantly, AEPS activated Nrf2 signaling pathway by promoting nuclear translocation of Nrf2. However, all-trans-retinoic acid (ATRA), an Nrf2 inhibitor, reversed the effects on AEPS to activation of Nrf2, enhancement of antioxidant, alleviation of kidney injury, restoration of kidney function, prevention of apoptotic, and facilitation of lead exclusion. In brief, AEPS showed kidney protective effect and facilitated lead-expulsion in an Nrf2-dependent manner.

Polysaccharide from Flammulina velutipes residues protects mice from Pb poisoning by activating Akt/GSK3β/Nrf-2/HO-1 signaling pathway and modulating gut microbiota

Lead (Pb) can cause damages to the brain, liver, kidney, endocrine and other systems. Flammulina velutipes residues polysaccharide (FVRP) has been reported to exhibit anti-heavy metal toxicity on yeast, but its regulating mechanism is unclear. Therefore, the protective effect and the underlying mechanism of FVRP on Pb-intoxicated mice were investigated. The results showed that FVRP could reduce liver and kidney function indexes, serum inflammatory factor levels, and increase antioxidant enzyme activity of Pb-poisoned mice. FVRP also exhibited a protective effect on histopathological damages in organs of Pb-intoxicated mice. Furthermore, FVRP attenuated Pb-induced kidney injury by inhibiting apoptosis via activating the Akt/GSK3β/Nrf-2/HO-1 signaling pathway. In addition, based on 16 s rRNA and ITS-2 sequencing data, FVRP regulated the imbalance of gut microbiota to alleviate the damage of Pb-poisoned mice by increasing the abundance of beneficial microbiota (Lachnospiraceae, Lactobacillaceae, Saccharomyces and Mycosphaerella) and decreasing the abundance of harmful microbiota (Muribaculaceae and Pleosporaceae). In conclusion, FVRP inhibited kidney injury in Pb-poisoned mice by inhibiting apoptosis via activating Akt/GSK3β/Nrf-2/HO-1 signaling pathway, and regulating gut fungi and gut bacteria. This study not only revealed the role of gut fungi in Pb-toxicity, but also laid a theoretical foundation for FVRP as a natural drug against Pb-toxicity.