Impact of circadian clock protein Bmal1 on experimentally-induced periodontitis-associated renal injury.

OBJECTIVES: To investigate the mechanism of circadian clock protein Bmal1 (Bmal1) on renal injury with chronic periodontitis, we established an experimental rat periodontitis model. METHODS: Twelve male Wistar rats were randomly divided into control and periodontitis groups (n=6, each group). The first maxillary molars on both sides of the upper jaw of rats with periodontitis were ligated by using orthodontic ligature wires, whereas the control group received no intervention measures. After 8 weeks, clinical periodontal parameters, including probing depth, bleeding index, and tooth mobility, were evaluated in both groups. Micro-CT scanning and three-dimensional image reconstruction were performed on the maxillary bones of the rats for the assessment of alveolar bone resorption. Histopatholo-gical observations of periodontal and renal tissues were conducted using hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) staining. Renal function indicators, such as creatinine, albumin, and blood urea nitrogen levels, and oxidative stress markers, including superoxide dismutase, glutathione, and malondialdehyde levels, were measured using biochemical assay kits. MitoSOX red staining was used to detect reactive oxygen species (ROS) content in the kidneys. The gene and protein expression levels of Bmal1, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in rat renal tissues were assessed using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemical staining. RESULTS: Micro-CT and HE staining results showed significant bone resorption and attachment loss in the maxillary first molar region of the periodontitis group. Histological examination through HE and PAS staining revealed substantial histopathological damage to the renal tissues of the rats in the periodontitis group. The findings of the assessment of renal function and oxidative stress markers indicated that the periodontitis group exhibited abnormal levels of oxidative stress, whereas the renal function levels showed abnormalities without statistical significance. MitoSOX Red staining results showed that the content of ROS in the renal tissue of the periodontitis group was significantly higher than that of the control group, and RT-qPCR and immunohistochemistry results showed that the expression levels of Bmal1, Nrf2, and HO-1 in the renal tissues of the rats in the periodontitis group showed a decreasing trend. CONCLUSIONS: Circadian clock protein Bmal1 plays an important role in the oxidative damage process involved in the renal of rats with periodontitis.

Tailored Trojan horse nanocarriers for enhanced redox-responsive drug delivery.

Redox-responsive anti-tumor nanomedicine is appealing in improving the therapeutic efficacy and patient compliance. However, the thiol-disulfide exchange reaction is reversible and kinetically very slow, resulting in poor drug release and delayed onset of drug action. To address this issue, a tailored Trojan horse nanocarrier is designed with pH-labile zeolitic imidazolate framework-8 (ZIF-8) as the core and disulfide-linked amphiphilic polymer-drug conjugate as the steric shell. A potent reductant, tris(3-hydroxypropyl)phosphine (THPP) is loaded in ZIF-8 and capped by myristyl alcohol. At low pH (e.g. endosome and lysosome), the collapse of ZIF-8 can induce the liberation of THPP that further cleaves the disulfide bond and release the drug post self-immolation. As the reaction between THPP and disulfide is both thermodynamically and kinetically favored, the drug release rate can be boosted. The proof-of-concept is demonstrated both in 4T1 murine mammary carcinoma cells and 4T1 tumor-bearing mice with curcumin as the model drug. Compared to the control nanosystem without THPP, the tailored nanocarrier can significantly enhance the drug release and hence therapeutic efficacy, which is demonstrated by the assays of cell viability, tumor growth inhibition, and histological staining. Such strategy can extend to a plethora of thiol-free cargos for controlled intracellular delivery.

A novel approach for the efficient extraction of silybin from milk thistle fruits.

BACKGROUND: Milk Thistle fruit is an important herb popularly consumed worldwide for a very long time. Silybin is the main bioactive constituent of the herb, and it has been approved by US Food and Drug Administration (FDA) as a medicine to treat liver diseases. Presently, using conventional technology, the meal of Milk Thistle fruit is used as the raw material to extract silybin. OBJECTIVE: To investigate the necessity of detaching husk from kernel of the herb and also to propose a novel approach to enhance the extraction technology in pharmaceutical practices. MATERIALS AND METHODS: The husk of Milk Thistle fruit was detached from the kernel of the herb using an automatic huller specially designed for this application. The husk and the meal of Milk Thistle fruit was subsequently refluxed, separately, with production rate of silybin as index for comparison of their extraction effect. RESULTS: The highest production rate was achieved under optimized condition. The husk was extracted 2 times (3 hrs each) using ethyl acetate, and the ratio of solvent to raw material was 8:1. The extract was allowed to be crystallized out. CONCLUSION: The separation of kernel from the husk of Milk Thistle fruit and using only the husk as raw material can largely enhance the extraction of silybin.