Chrysin-loaded PEGylated liposomes protect against alloxan-induced diabetic neuropathy in rats: the interplay between endoplasmic reticulum stress and autophagy.

BACKGROUND: Diabetic neuropathy (DN) is recognized as a significant complication arising from diabetes mellitus (DM). Pathogenesis of DN is accelerated by endoplasmic reticulum (ER) stress, which inhibits autophagy and contributes to disease progression. Autophagy is a highly conserved mechanism crucial in mitigating cell death induced by ER stress. Chrysin, a naturally occurring flavonoid, can be found abundantly in honey, propolis, and various plant extracts. Despite possessing advantageous attributes such as being an antioxidant, anti-allergic, anti-inflammatory, anti-fibrotic, and anticancer agent, chrysin exhibits limited bioavailability. The current study aimed to produce a more bioavailable form of chrysin and discover how administering chrysin could alter the neuropathy induced by Alloxan in male rats. METHODS: Chrysin was formulated using PEGylated liposomes to boost its bioavailability and formulation. Chrysin PEGylated liposomes (Chr-PLs) were characterized for particle size diameter, zeta potential, polydispersity index, transmission electron microscopy, and in vitro drug release. Rats were divided into four groups: control, Alloxan, metformin, and Chr-PLs. In order to determine Chr- PLs' antidiabetic activity and, by extension, its capacity to ameliorate DN, several experiments were carried out. These included measuring acetylcholinesterase, fasting blood glucose, insulin, genes dependent on autophagy or stress in the endoplasmic reticulum, and histopathological analysis. RESULTS: According to the results, the prepared Chr-PLs exhibited an average particle size of approximately 134 nm. They displayed even distribution of particle sizes. The maximum entrapment efficiency of 90.48 ± 7.75% was achieved. Chr-PLs effectively decreased blood glucose levels by 67.7% and elevated serum acetylcholinesterase levels by 40% compared to diabetic rats. Additionally, Chr-PLs suppressed the expression of ER stress-related genes (ATF-6, CHOP, XBP-1, BiP, JNK, PI3K, Akt, and mTOR by 33%, 39.5%, 32.2%, 44.4%, 40.4%, 39.2%, 39%, and 35.9%, respectively). They also upregulated the miR-301a-5p expression levels by 513% and downregulated miR-301a-5p expression levels by 65%. They also boosted the expression of autophagic markers (AMPK, ULK1, Beclin 1, and LC3-II by 90.3%, 181%, 109%, and 78%, respectively) in the sciatic nerve. The histopathological analysis also showed that Chr-PLs inhibited sciatic nerve degeneration. CONCLUSION: The findings suggest that Chr-PLs may be helpful in the protection against DN via regulation of ER stress and autophagy.

Heat stress disrupts spermatogenesis via modulation of sperm-specific calcium channels in rats.

Heat is a detrimental environmental stressor that disrupts spermatogenesis and results in male infertility. Previous investigations have shown that heat stress reduces the motility, number, and fertilization ability of living spermatozoa. Sperm hyperactivation, capacitation, acrosomal reaction, and chemotaxis towards the ova are regulated by the cation channel of sperm (CatSper). This sperm-specific ion channel triggers the influx of calcium ions into sperm cells. The aim of this study in rats was to investigate whether heat treatment affected the expression levels of CatSper-1 and -2, together with the sperm parameters, testicular histology and weight. The rats were exposed to heat stress for 6 days and the cauda epididymis and testis were collected 1, 14, and 35 days after heat treatment to measure sperm parameters, gene and protein expression, testicular weight, and histology. Interestingly, we found that heat treatment caused a notable downregulation of CatSper-1 and -2 expression at all three time points. In addition, there were significant reductions in sperm motility and number and an increase in the percentage of abnormal sperm at 1 and 14 days, with cessation of sperm production at 35 days. Furthermore, expression of the steroidogenesis regulator, 3 beta-hydroxysteroid dehydrogenase (3ß-HSD) was upregulated in the 1-, 14- and 35-day samples. Heat treatment also upregulated the expression of the apoptosis regulator, BCL2-associated X protein (BAX), decreased testicular weight, and altered testicular histology. Therefore, our data showed for the first time that heat stress downregulated CatSper-1 and -2 in the rat testis, and that this may be a mechanism involved in heat stress-induced impairment of spermatogenesis.

Effective Anticancer Therapy by Combination of Nanoparticles Encapsulating Chemotherapeutic Agents and Weak Electric Current.

Delivery of medicines using nanoparticles via the enhanced permeability and retention (EPR) effect is a common strategy for anticancer chemotherapy. However, the extensive heterogeneity of tumors affects the applicability of the EPR effect, which needs to overcome for effective anticancer therapy. Previously, we succeeded in the noninvasive transdermal delivery of nanoparticles by weak electric current (WEC) and confirmed that WEC regulates the intercellular junctions in the skin by activating cell signaling pathways (J. Biol. Chem., 289, 2014, Hama et al.). In this study, we applied WEC to tumors and investigated the EPR effect with polyethylene glycol (PEG)-modified doxorubicin (DOX) encapsulated nanoparticles (DOX-NP) administered via intravenous injection into melanoma-bearing mice. The application of WEC resulted in a 2.3-fold higher intratumor accumulation of nanoparticles. WEC decreased the amount of connexin 43 in tumors while increasing its phosphorylation; therefore, the enhancing of intratumor delivery of DOX-NP is likely due to the opening of gap junctions. Furthermore, WEC combined with DOX-NP induced a significant suppression of tumor growth, which was stronger than with DOX-NP alone. In addition, WEC alone showed tumor growth inhibition, although it was not significant compared with non-treated group. These results are the first to demonstrate that effective anticancer therapy by combination of nanoparticles encapsulating chemotherapeutic agents and WEC.

The Potential Effects of Quercetin-Loaded Nanoliposomes on Amoxicillin/Clavulanate-Induced Hepatic Damage: Targeting the SIRT1/Nrf2/NF-κB Signaling Pathway and Microbiota Modulation.

Amoxicillin/clavulanate (Co-Amox), a commonly used antibiotic for the treatment of bacterial infections, has been associated with drug-induced liver damage. Quercetin (QR), a naturally occurring flavonoid with pleiotropic biological activities, has poor water solubility and low bioavailability. The objective of this work was to produce a more bioavailable formulation of QR (liposomes) and to determine the effect of its intraperitoneal pretreatment on the amelioration of Co-Amox-induced liver damage in male rats. Four groups of rats were defined: control, QR liposomes (QR-lipo), Co-Amox, and Co-Amox and QR-lipo. Liver injury severity in rats was evaluated for all groups through measurement of serum liver enzymes, liver antioxidant status, proinflammatory mediators, and microbiota modulation. The results revealed that QR-lipo reduced the severity of Co-Amox-induced hepatic damage in rats, as indicated by a reduction in serum liver enzymes and total liver antioxidant capacity. In addition, QR-lipo upregulated antioxidant transcription factors SIRT1 and Nrf2 and downregulated liver proinflammatory signatures, including IL-6, IL-1ß, TNF-α, NF-κB, and iNOS, with upregulation in the anti-inflammatory one, IL10. QR-lipo also prevented Co-Amox-induced gut dysbiosis by favoring the colonization of Lactobacillus, Bifidobacterium, and Bacteroides over Clostridium and Enterobacteriaceae. These results suggested that QR-lipo ameliorates Co-Amox-induced liver damage by targeting SIRT1/Nrf2/NF-κB and modulating the microbiota.