Protective Effect of 2-APB on Testicular Ischemia-Reperfusion Injury in Rats

The Action of 2-Aminoethyldiphenyl Borinate on the Pulmonary Arterial Hypertension and Remodeling of High-Altitude Hypoxemic Lambs

Calcium signaling is key for the contraction, differentiation, and proliferation of pulmonary arterial smooth muscle cells. Furthermore, calcium influx through store-operated channels (SOCs) is particularly important in the vasoconstrictor response to hypoxia. Previously, we found a decrease in pulmonary hypertension and remodeling in normoxic newborn lambs partially gestated under chronic hypoxia, when treated with 2-aminoethyldiphenyl borinate (2-APB), a non-specific SOC blocker. However, the effects of 2-APB are unknown in neonates completely gestated, born, and raised under environmental hypoxia. Accordingly, we studied the effects of 2-APB-treatment on the cardiopulmonary variables in lambs under chronic hypobaric hypoxia. Experiments were done in nine newborn lambs gestated, born, and raised in high altitude (3,600 m): five animals were treated with 2-APB [intravenous (i.v.) 10 mg kg^–1] for 10 days, while other four animals received vehicle. During the treatment, cardiopulmonary variables were measured daily, and these were also evaluated during an acute episode of superimposed hypoxia, 1 day after the end of the treatment. Furthermore, pulmonary vascular remodeling was assessed by histological analysis 2 days after the end of the treatment. Basal cardiac output and mean systemic arterial pressure (SAP) and resistance from 2-APB- and vehicle-treated lambs did not differ along with the treatment. Mean pulmonary arterial pressure (mPAP) decreased after the first day of 2-APB treatment and remained lower than the vehicle-treated group until the third day, and during the fifth, sixth, and ninth day of treatment. The net mPAP increase in response to acute hypoxia did not change, but the pressure area under the curve (AUC) during hypoxia was slightly lower in 2-APB-treated lambs than in vehicle-treated lambs. Moreover, the 2-APB treatment decreased the pulmonary arterial wall thickness and the α-actin immunoreactivity and increased the luminal area with no changes in the vascular density. Our findings show that 2-APB treatment partially reduced the contractile hypoxic response and reverted the pulmonary vascular remodeling, but this is not enough to normalize the pulmonary hemodynamics in chronically hypoxic newborn lambs.

Two Benzene Rings with a Boron Atom Comprise the Core Structure of 2-APB Responsible for the Anti-Oxidative and Protective Effect on the Ischemia/Reperfusion-Induced Rat Heart Injury

To identify the core structure of 2-aminoethoxydiphenyl borate (2-APB) responsible for the anti-oxidative and protective effect on the ischemia/reperfusion (I/R)-induced heart injury, various 2-APB analogues were analyzed, and several antioxidant assays were performed. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Myocardial infarct size was quantified using triphenyl tetrazolium chloride (TTC) staining. The levels of tumor necrosis factor-alpha (TNF-α) and cleaved-caspase-3 protein were evaluated as an indicator for the anti-inflammatory and anti-apoptotic effect, respectively. Our data show that 2-APB, diphenylborinic anhydride (DPBA) and 3-(diphenylphosphino)-1-propylamine (DP3A) all exerted the anti-oxidative activity, but only 2-APB and DPBA can scavenge H₂O₂. 2-APB and DPBA can potently inhibit hydrogen peroxide (H₂O₂)- and hypoxanthine/xanthine oxidase (HX/XOD)-induced increases in intracellular H₂O₂ and H9c2 cell death. 2-APB and DPBA were able to decrease the I/R-induced adult rat cardiomyocytes death, myocardial infarct size, and the levels of malondialdehyde (MDA) and creatine kinase-MB (CK-MB). Our results suggest that the two benzene rings with a boron atom comprise the core structure of 2-APB responsible for the anti-oxidative effect mediated through the reaction with H₂O₂ and generation of phenolic compounds, which in turn reduced the I/R-induced oxidative stress and injury in the rat heart.

CaMK4-dependent phosphorylation of Akt/mTOR underlies Th17 excessive activation in experimental autoimmune prostatitis

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) is a complicated syndrome characterized by genitourinary pain in the absence of bacterial infection. Th17 cell-driven autoimmunity has been proposed as a cause of CP/CPPS. However, the factors that promote Th17-driven autoimmunity in experimental autoimmune prostatitis (EAP) and the molecular mechanisms are still largely unknown. Here, we showed that Th17 cells were excessively activated, and blockade of IL-17A could effectively ameliorate various symptoms in EAP. Furthermore, we revealed that calcium/calmodulin-dependent kinase Ⅳ (CaMK4), especially Thr196 p-CaMK4 was increased in the Th17 cells of the EAP group, which were activated by intracellular cytosolic Ca2+ . Pharmacologic and genetic inhibition of CaMK4 decreased the proportion of Th17 cells, and the protein and mRNA level of IL-17A, IL-22, and RORγt. The phosphorylation of CaMK4 was dependent on the increase in intracellular cytosolic Ca2+ concentration in Th17 cells. A mechanistic study demonstrated that inhibition of CaMK4 reduced IL-17A production by decreasing the phosphorylation of Akt-mTOR, which was well accepted to positively regulate Th17 differentiation. Collectively, our results demonstrated that Ca2+ -CaMK4-Akt/mTOR-IL-17A axis inhibition may serve as a promising therapeutic strategy for CP/CPPS.

Electron Microscopic and Immunohistochemical Examination of the Effect of 2-Aminoethoxydiphenyl Borate on Optic Nerve Injury in A Rat Model

Objective

We conducted this study to explore the possible protective effect of 2-aminoethoxydiphenyl borate (2-APB) on experimentally induced optic nerve injury in an acute ischemia-reperfusion (AIR) model.

Materials and Methods

A total of 30 Wistar albino rats were randomly divided into sham, AIR, and AIR+treatment (AIR10) groups. In the sham group, AIR model was not created. In the AIR group, AIR model was created without the administration of drug. In the AIR10 group, 2-APB was administered 10 min before reperfusion.

Results

Tissue samples were subjected to histological, immunohistochemical, and electron microscopic procedures. Histopathological examination revealed intense hypertrophic cells, more glial cells, capillary dilatation, and intense demyelination areas in the AIR group compared to those in the sham and AIR10 groups. Immunohistochemical staining demonstrated an increase in Orai1 and STIM1 immunoreactivity in the AIR group but less intense staining in the AIR10 group. Electron microscopy revealed injury in optic nerve axons in the AIR group, whereas this type of injury occurred to a lesser extent in the AIR10 group.

Conclusion

In rats, store-operated Ca²⁺ entry in the cell had an essential role in optic nerve ischemia-reperfusion injury, and 2-ABP may have a protective effect on optic nerve injury caused due to AIR.

Boron's neurophysiological effects and tumoricidal activity on glioblastoma cells with implications for clinical treatment

Purpose: To define the actions of boron on normal neurophysiology and glioblastoma growth. Materials and Methods: PubMed and other relevant databases were searched. Results: Discovery of novel boron compounds in treatment of glioblastoma is being actively investigated, but the majority of such studies is focused on the synthesis of boron compounds as sensitizers to Boron Neutron Capture Therapy (BNCT). Nonetheless, the translational functionality of boron compounds is not limited to BNCT as many boron compounds possess direct tumoricidal activity and there is substantial evidence that certain boron compounds can cross the blood-brain barrier. Moreover, boron-containing compounds interfere with several tumorigenic pathways including intratumoral IGF-I levels, molybdenum Fe-S containing flavin hydroxylases, glycolysis, Transient Receptor Potential (TRP) and Store Operated Calcium Entry (SOCE) channels. Conclusions: Boron compounds deserve to be studied further in treatment of systemic cancers and glioblastoma due to their versatile antineoplastic functions.

Testicular compartment syndrome: an overview of pathophysiology, etiology, evaluation, and management

Testicular compartment syndrome (TCS) refers to the impairment of microcirculation in the testicle due to either increased venous resistance or extraluminal compression, which leads to hypoxia. TCS releases oxidants through hypoxia and ischemia/reperfusion injury (IRI). The pathophysiology, etiology, evaluation, and management of TCS are reviewed. Based on the properties of TCS, specific causes, e.g., varicocele, hydrocele, orchitis, cryptorchidism, and scrotal hernia, are suggested and categorized. The oxidant-induced stress from TCS may explain the correlations between these causes and infertility. A chief shortcoming of current imaging modalities is that they detect TCS late after it has progressed to impair the macrocirculation of the testicle. We propose frequent sequential periodic power Doppler ultrasonography to monitoring for earlier detection. Intraoperatively, TCS can be diagnosed by the dull purple appearance of a hypoxic testicle and by tissue pressures above 30 mmHg. When compartment pressure is low, the underlying etiology must be promptly treated. During acute presentation, an incision of the resilient tunica albuginea may be necessary. A great challenge of treating TCS is restoring microcirculation while minimizing IRI; concomitant antioxidant therapy secondary to treatment may be effective and harmless at the least. Because testicular oxidant stress is common in infertility and since TCS can cause such a stress, TCS may be a larger factor in infertility than currently suspected.