Procyanidin B2 Alleviates Palmitic Acid-Induced Injury in HepG2 Cells via Endoplasmic Reticulum Stress Pathway

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome featuring ectopic lipid accumulation in hepatocytes. NAFLD has been a severe threat to humans with a global prevalence of over 25% yet no approved drugs for the treatment to date. Previous studies showed that procyanidin B2 (PCB2), an active ingredient from herbal cinnamon, has an excellent hepatoprotective effect; however, the mechanism remains inconclusive. The present study aimed to investigate the protective effect and underlying mechanism of PCB2 on PA-induced cellular injury in human hepatoma HepG2 cells. Our results showed that PA-induced oxidative stress, calcium disequilibrium, and subsequent endoplasmic reticulum stress (ERS) mediated cellular injury, with elevated protein levels of GRP78, GRP94, CHOP, and hyperphosphorylation of PERK and IRE1α as well as the increased ratio of Bax/Bcl-2, which was restored by PCB2 in a concentration-dependent manner, proving the excellent antiapoptosis effect. In addition, 4-phenylbutyric acid (4-PBA), the ER stress inhibitor, increased cell viability and decreased protein levels of GRP78 and CHOP, which is similar to PCB2, and thapsigargin (TG), the ER stress agonist, exhibited conversely meanwhile partly counteracted the hepatic protection of PCB2. What is more, upregulated protein expression of p-IKKα/β, p-NF-κB p65, NLRP3, cleaved caspase 1, and mature IL-1β occurred in HepG2 cells in response to PA stress while rescued with the PCB2 intervention. In conclusion, our study demonstrated that PA induces ERS in HepG2 cells and subsequently activates downstream NLRP3 inflammasome-mediated cellular injury, while PCB2 inhibits NLRP3/caspase 1/IL-1β pathway, inflammation, and apoptosis with the presence of ERS, thereby promoting cell survival, which may provide pharmacological evidence for clinical approaches on NAFLD.

Cellular Injury and Death

Cell death occurs after an irreversible insult or stress overwhelms the cell’s compensatory mechanisms of homeostasis and repair. Cellular necrosis, apoptosis, and autophagy are increasingly understood to be interconnected biochemical processes that may coexist in vascular, inflammatory, and neurodegenerative conditions. Traditional classifications of cell death pathways are 1) necrosis; 2) programmed nuclear cell death, including apoptosis; and 3) autophagy. These processes occur in the context of variable cause and severity of injury, variable cellular metabolic and energy states, and variable fitness to compensate.

Comparison of troponin 1 level among the patients who underwent coronary artery bypass grafting with and without adenosine as an adjunct to blood cardioplegia

Background: Cellular injury is not avoidable with current cardioplegic solutions. No method of cardioplegia has been shown to completely protect the myocardium against cellular injury. The objective of the study is to evaluate the safety and efficacy of adenosine as an adjunct to blood cardioplegia during CABG.Methods: A retrospective study at GMCT, Thiruvananthapuram in CABG patients for 3 years from January 1, 2016, to December 31, 2019, between the age of 40 and 70 years. Patients with other chronic diseases and pre-operative echo showing EF less than 40% were excluded. The study variables were level of troponin I intra and postoperative period, time taken for cardiac standstill, number of days in ventilator, ICU and on inotropic supports. Also, postoperative lactate levels, changes in RWMA and EF.Results: Of the total 75 subjects, 40 got adenosine while 35 didn’t. The mean post op EF for those who got adenosine is 55.30 and without is 56.46. The mean time of cardiac stand still with adenosine is 12.88 sec and without is 16.51 sec. The mean post op troponin I level in those who got adenosine is 6.43 and without is 12.94.Conclusions: Decreased level of troponin I and inotropic requirement suggests that an optimal myocardial protection. Adenosine usage helps in early extubation but doesn’t alter the number of days in ICU. Adenosine is safe, gives more rapid cardiac arrest but it will not alter the post op left ventricular function.

Optimized models of xenobiotic-induced oxidative stress in HepG2 cells

Purpose: To evaluate the molecular impact of ethanol, sodium selenite, and tert-butyl hydroperoxide (TBHP) on oxidant-antioxidant balance in HepG2 cells to establish an optimized oxidative stress model of HepG2 cells. Methods: HepG2 cells were treated with ethanol (10 - 500 mM) and sodium selenite (1 - 10 µM) for 24 and 48 h and with TBHP (50 - 200 µM) for 3 and 24 h, respectively. Biomarkers for cellular injury, ie, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and malondialdehyde (MDA), and for antioxidant system, i.e., superoxide dismutase (SOD), catalase (CAT), and total glutathione content, were determined. Results: All treatments increased the levels of LDH, AST, ALT, and MDA but decreased SOD and CAT activities and the total glutathione content in HepG2 cells. Oxidative stress was induced by these oxidative stressors in HepG2 cells via oxidant-antioxidant imbalance, with TBHP (100 µM, 3 h) acting as a powerful oxidant based on the minimal time to induce oxidative stress. The antioxidants, ascorbic acid and gallic acid, improved oxidant-antioxidant imbalance against xenobiotic-induced oxidative stress in HepG2 cells. Conclusion: These oxidative stress models are suitable for investigating the antioxidant and/or hepatoprotective potential of chemicals, including natural compounds.

Laser-Induced Nuclear Damage Signaling and Communication in Astrocyte Networks Through Parp-Dependent Calcium Oscillations

Astrocytes are known to respond to various perturbations with oscillations of calcium, including to cellular injury. Less is known about astrocytes’ ability to detect DNA/nuclear damage. This study looks at changes in calcium signaling in response to laser-induced nuclear damage using a NIR Ti:Sapphire laser. Primary astrocytes derived from genetically engineered mice expressing G6Campf genetically encoded calcium indicator were imaged in response to laser induced injury. Combining laser nanosurgery with calcium imaging of primary astrocytes allow for spatial and temporal observation of the astrocyte network in response to nuclear damage. Nuclear damage resulted in a significant increase in calcium peak frequency, in nuclear damaged cells and astrocytes directly attached to it. The increase in calcium event frequency observed in response to damage and the transfer to neighboring cells was not observed in cytoplasm damaged cells. Targeted astrocytes and attached neighboring cells treated with Poly (ADP-ribose) polymerase inhibitor have a significantly lower peak frequency following laser damage to the nucleus. These results indicate the increase in calcium peak frequency following nuclear damage is poly (ADP-ribose) polymerase dependent.

Effect of Indian Polyvalent Antivenom in the Prevention and Reversal of Local Myotoxicity Induced by Common Cobra (Naja naja) Venom from Sri Lanka In Vitro

Bites by many Asiatic and African cobras (Genus: Naja) cause severe local dermonecrosis and myonecrosis, resulting in permanent disabilities. We studied the time scale in which two Indian polyvalent antivenoms, VINS and Bharat, remain capable of preventing or reversing in vitro myotoxicity induced by common cobra (Naja naja) venom from Sri Lanka using the chick biventer cervicis nerve-muscle preparation. VINS fully prevented while Bharat partially prevented (both in manufacturer recommended concentrations) the myotoxicity induced by Naja naja venom (10 µg/mL) when added to the organ baths before the venom. However, both antivenoms were unable to reverse the myotoxicity when added to organ baths 5 and 20 min post-venom. In contrast, physical removal of the venom from the organ baths by washing the preparation 5 and 20 min after the venom resulted in full and partial prevention of the myotoxicity, respectively, indicating the lag period for irreversible cellular injury. This suggests that, although the antivenoms contain antibodies against cytotoxins of the Sri Lankan Naja naja venom, they are either unable to reach the target sites as efficiently as the cytotoxins, unable to bind efficiently with the toxins at the target sites, or the binding with the toxins simply fails to prevent the toxin-target interactions.

Protective Effects of Curcumin on Sperm and Stereological Parameters in Testes of Formaldehyde-Exposed NMRI Mice: An Experimental Study

Background and Aims: Formaldehyde (FA) exposure is an important cause of cellular injury and oxidative damage in testis, leading to infertility. This study aimed to assess the protective effects of curcumin on sperm and stereological parameters in testes from formaldehyde-exposed NMRI mice. Materials and Methods: At 6-8 weeks of age, 24 adult male NMRI mice weighing 30-35 g were categorized into four groups (n=6) based on the treatment they received: Group І (control) received no treatment, group ΙΙ received FA (10 mg/kg), group ΙΙΙ received FA (10 mg/kg) and curcumin (100 mg/kg), and group IV (Solvent) received dimethyl sulfoxide (0.2 ml/day). Materials were administered intraperitoneally for 35 days. After excision, epididymis tissues were placed in 1 mL aliquots of Ham’s F10 medium at 37˚C for 20 min and were then used in analyses of sperm parameters. Testes were fixed and stained with Hematoxylin & Eosin to investigate stereological indices. We also determined lipid peroxidation levels using malondialdehyde assays. Results: Mean sperm parameters (count, motility, viability, and morphology) differed significantly between groups ΙΙ and ΙΙΙ (p≤0.001). Stereological indices, including Leydig and spermatogonia cell numbers and surface-to-volume ratios of seminiferous tubules were significantly higher in group ΙΙΙ than in group ΙΙ (p≤0.001) . Finally, malondialdehyde levels in group III were significantly lower than in group II (p=0.001). Conclusions: The data showed that the curcumin, as an antioxidant, reduced FA-induced damage in sperm parameters and stereological indices in mice testes.