Mycophenolic Acid Induces the Intestinal Epithelial Barrier Damage through Mitochondrial ROS

Mycophenolic acid (MPA) may cause gastrointestinal adverse effects by damaging the intestinal epithelial barrier, the underlying mechanisms remain elusive. Studies have demonstrated that oxidative stress caused by reactive oxygen species (ROS) is linked to tight junction (TJ) proteins and apoptosis, both of which cause abnormalities in intestinal barrier function. Mitochondria, one of the main sources of ROS and abnormally high levels of ROS are linked to mitochondrial dysfunction. The aim of this study was to investigate whether MPA induces intestinal barrier dysfunction through regulation of the mitochondrial ROS. MPA-induced intestinal injury model in Kunming mice and Caco-2 cells. The effect of MPA on Caco-2 cell viability was measured by MTT; tissue diamine oxidase and endotoxin expression were determined by ELISA; expression of total proteins of ZO-1, occludin, Bax, Bcl-2, and mitochondrial proteins of Cytochrome C and Bax was measured by Western blot; and the localization of Cytochrome C with MitoTraker was observed by immunofluorescence staining. Caco-2 cell apoptosis, ROS levels, and mitochondrial membrane potential were detected by flow cytometry, while intramitochondrial ROS levels were observed by MitoSOX fluorescence staining. The results showed that MPA increased intracellular and mitochondrial ROS production to promote oxidative stress and the antioxidant NAC effectively restored ZO-1 and occludin expressions, reduced apoptosis in intestinal epithelial cells. Furthermore, we found that low concentrations of MPA caused mitochondrial damage, induced hyperpolarization of the mitochondrial membrane potential and the translocation of Cytochrome C and Bax proteins from the cytoplasm to the mitochondria. The mitochondrial protectant SS-31 reduces intracellular and intramitochondrial ROS, upregulates TJ, and reduces apoptosis. Our studies suggest that MPA-induced intestinal barrier dysfunction in vivo and in vitro is mediated, at least in part, by impairing mitochondrial function and promoting oxidative stress

Therapeutic Potential of Diosgenin and Its Major Derivatives against Neurological Diseases: Recent Advances

Diosgenin (DG), a well-known steroidal sapogenin, is present abundantly in medicinal herbs such as Dioscorea rhizome, Dioscorea villosa, Trigonella foenum-graecum, Smilax China, and Rhizoma polgonati. DG is utilized as a major starting material for the production of steroidal drugs in the pharmaceutical industry. Due to its wide range of pharmacological activities and medicinal properties, it has been used in the treatment of cancers, hyperlipidemia, inflammation, and infections. Numerous studies have reported that DG is useful in the prevention and treatment of neurological diseases. Its therapeutic mechanisms are based on the mediation of different signaling pathways, and targeting these pathways might lead to the development of effective therapeutic agents for neurological diseases. The present review mainly summarizes recent progress using DG and its derivatives as therapeutic agents for multiple neurological disorders along with their various mechanisms in the central nervous system. In particular, those related to therapeutic efficacy for Parkinson’s disease, Alzheimer’s disease, brain injury, neuroinflammation, and ischemia are discussed. This review article also critically evaluates existing limitations associated with the solubility and bioavailability of DG and discusses imperatives for translational clinical research. It briefly recapitulates recent advances in structural modification and novel formulations to increase the therapeutic efficacy and brain levels of DG. In the present review, databases of PubMed, Web of Science, and Scopus were used for studies of DG and its derivatives in the treatment of central nervous system diseases published in English until December 10, 2019. Three independent researchers examined articles for eligibility. A total of 150 articles were screened from the above scientific literature databases. Finally, a total of 46 articles were extracted and included in this review. Keywords related to glioma, ischemia, memory, aging, cognitive impairment, Alzheimer, Parkinson, and neurodegenerative disorders were searched in the databases based on DG and its derivatives

Activation of dorsal horn cannabinoid CB2 receptor suppresses the expression of P2Y12 and P2Y13 receptors in neuropathic pain rats

Abstract Background More evidence suggests that dorsal spinal cord microglia is an important site contributing to CB2 receptor-mediated analgesia. The upregulation of P2Y12 and P2Y13 purinoceptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not known whether the expression of P2Y12 and P2Y13 receptors at spinal dorsal horn will be influenced after CB2 receptor activation in neuropathic pain rats. Methods Chronic constriction injury (CCI) and intrathecal ADPbetaS injection were performed in rats to induce neuropathic pain. The paw withdrawal latency (PWL) was used to evaluate thermal hyperalgesia in neuropathic rats. The expression of P2Y12 and P2Y13 receptors, p-p38MAPK, and NF-kappaBp65 was detected with RT-PCR and western blotting analysis. Results Treatment with AM1241 produces a pronounced inhibition of CCI-induced thermal hyperalgesia and significantly inhibited the increased expression of P2Y12 and P2Y13 receptors at the mRNA and protein levels, which open up the possibility that P2Y12 and P2Y13 receptor expression are downregulated by CB2 receptor agonist AM1241 in CCI rats. Western blot analysis demonstrated that AM1241 reduced the elevated expression of p-p38MAPK and NF-κBp65 in the dorsal spinal cord induced by CCI. After administration with either SB203580 (p38MAPK inhibitor) or PDTC (NF-kappaB inhibitor), the levels of P2Y13 receptor expression in the dorsal spinal cord were lower than those in the CCI group. However, in CCI rats, the increased expression of P2Y12 receptor was prevented by intrathecal administration of PDTC but not by SB203580. In addition, minocycline significantly decreased the increased expression of P2Y12 and P2Y13 receptors. The similar results can be observed in ADPbetaS-treated rats. Intrathecal injection of ADPbataS causes thermal hyperalgesia and increased expression of P2Y12 and P2Y13 receptors in the dorsal spinal cord of naive rats. Moreover, intrathecal injection of AM1241 alleviates pain response and reduces the elevated expression of P2Y12 and P2Y13 receptors, p-p38MAPK, and NF-κBp65 in the dorsal spinal cord of ADPbetaS-treated rats. Intrathecal injection of SB203580 significantly inhibited the ADPbetaS-induced P2Y13 receptor expression, without affecting P2Y12 receptor expression. However, treatment with either SB203580 or PDTC effectively inhibited P2Y13 receptor expression compared to ADPbetaS-treated rats. Conclusions In CCI- and ADPbetaS-treated rats, AM1241 pretreatment could efficiently activate CB2 receptor, while inhibiting p38MAPK and NF-kappaB activation in the dorsal spinal cord. CB2 receptor stimulation decreased P2Y13 receptor expression via p38MAPK/NF-kappaB signaling. On the other hand, CB2 receptor activation decreased P2Y12 receptor expression via p38MAPK-independent NF-kappaB signaling pathway

Preparation, Characterization and Pharmacokinetics of Tolfenamic Acid-Loaded Solid Lipid Nanoparticles

The clinical use of nonsteroidal anti-inflammatory drugs is limited by their poor water solubility, unstable absorption, and low bioavailability. Solid lipid nanoparticles (SLNs) exhibit high biocompatibility and the ability to improve the bioavailability of drugs with low water solubility. Therefore, in this study, a tolfenamic acid solid lipid nanoparticle (TA-SLN) suspension was prepared by a hot melt–emulsification ultrasonication method to improve the sustained release and bioavailability of TA. The encapsulation efficiency (EE), loading capacity (LC), particle size, polydispersity index (PDI), and zeta potential of the TA-SLN suspension were 82.50 ± 0.63%, 25.13 ± 0.28%, 492 ± 6.51 nm, 0.309 ± 0.02 and −21.7 ± 0.51 mV, respectively. The TA-SLN suspension was characterized by dynamic light scattering (DLS), fluorescence microscopy (FM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR) spectroscopy. The TA-SLN suspension showed improved sustained drug release in vitro compared with the commercially available TA injection. After intramuscular administration to pigs (4 mg/kg), the TA-SLN suspension displayed increases in the pharmacokinetic parameters Tmax, T1/2, and MRT0–∞ by 4.39-, 3.78-, and 3.78-fold, respectively, compared with TA injection, and showed a relative bioavailability of 185.33%. Thus, this prepared solid lipid nanosuspension is a promising new formulation

1ps passively mode-locked laser operation of Na, Yb : CaF2 crystal

Diode-pumped passively mode-locked laser operation of Yb3+,Na+:CaF2 single crystal has been demonstrated for the first time. By using a SESAM ( semiconductor saturable mirror), simultaneous transform-limited 1-ps passively mode-locked pulses, with the repetition rate of 183MHz, were obtained under the self-Q-switched envelope induced by the laser medium. The average output power of 360mW was attained at 1047nm for 3.34W of absorbed power at 976nm, and the corresponding pulse peak power arrived at 27kW, indicating the promising application of Yb3+,Na+-codoped CaF2 crystals in achieving ultra-short pulses and high pulse peak power. (c) 2005 Optical Society of America