SUMMARY: Using NADPH-diaphorase (NADPH-d) histochemistry, inducible nitric oxide synthase (iNOS)-immunohistochemistry and immunoblotting, we characterized the nitric oxide (NO)-producing neurons in the brain and thoracic ganglion of a shore crab subjected to a nociceptive chemical stimulus. Formalin injection into the cheliped evoked specific nociceptive behavior and neurochemical responses in the brain and thoracic ganglion of experimental animals. Within 5–10 min of injury, the NADPH-d activity increased mainly in the neuropils of the olfactory lobes and the lateral antenna I neuropil on the side of injury. Later, the noxious-induced expression of NADPH-d and iNOS was detected in neurons of the brain, as well as in segmental motoneurons and interneurons of the thoracic ganglion. Western blotting analysis showed that an iNOS antiserum recognized a band at 120 kDa, in agreement with the expected molecular mass of the protein. The increase in nitrergic activity induced by nociceptive stimulation suggests that the NO signaling system may modulate nociceptive behavior in crabs.

At present, the study of the neurotropic activity of polyunsaturated fatty acid ethanolamides (N-acylethanolamines) is becoming increasingly important. N-docosahexaenoylethanolamine (synaptamide, DHEA) is a highly active metabolite of docosahexaenoic acid (DHA) with neuroprotective, synaptogenic, neuritogenic, and anti-inflammatory properties in the nervous system. Synaptamide tested in the present study was obtained using a chemical modification of DHA isolated from squid Berryteuthis magister liver. The results of this study demonstrate the effects of synaptamide on the astroglial response to injury in the acute (1 day) and chronic (7 days) phases of mild traumatic brain injury (mTBI) development. HPLC-MS study revealed several times increase of synaptamide concentration in the cerebral cortex and serum of experimental animals after subcutaneous administration (10 mg/kg/day). Using immunohistochemistry, it was shown that synaptamide regulates the activation of GFAP- and S100β-positive astroglia, reduce nNOS-positive immunostaining, and stimulates the secretion of neurotrophin BDNF. Dynamics of superoxide dismutase production in synaptamide treatment confirm the antioxidant efficacy of the test compound. We found a decrease in TBI biomarkers such as GFAP, S100β, and IL-6 in the blood serum of synaptamide-treated experimental animals using Western blot analysis. The results indicate the high therapeutic potential of synaptamide in reducing the severity of the brain damage consequences.

The complex effect of oleoylethanolamide-based dietary supplement (OEA-DS) was studied in a model of diet-induced obesity in mice. Physiological, biochemical, and immunohistochemical methods were used to reveal differences in the changes in the weight of experimental animals, morphological changes in the spleen tissues, and changes in the cytokine expression profile in the spleen, blood plasma, and macrophage cell culture. First, it is shown that a hypercaloric diet high in carbohydrates and cholesterol led to the development of systemic inflammation, accompanied by organ morphological changes and increased production of proinflammatory cytokines. In parallel, the use of OEA-DS reduced the intensity of cellular inflammatory reactions, accompanied by a decrease in markers of cellular inflammation and proliferation, such as CD68, Iba-1, and Ki67 in the spleen tissue, and stabilized the level of proinflammatory cytokines (IL-1β, IL-6, TNFα) both in animals and in cell culture. In addition, in the macrophage cell culture (RAW264.7), it was shown that OEA-DS also suppressed the production of reactive oxygen species and nitrites in LPS-induced inflammation. The results of this study indicate the complex action of OEA-DS in obesity, which includes a reduction of systemic inflammation.

Background: Metabolic effects of oleoylethanolamide-based dietary supplement (OEA-DS) were studied in a model of dietary-induced obesity in mice. Obesity was induced by a 2-month high-fat, high-cholesterol diet, resulting in significant morphological changes in liver tissues and elevated cholesterol levels in the animals’ blood serum. Elevated levels of proinflammatory cytokines, oxidative stress, and hepatocyte apoptosis were also observed in the liver tissue. The aim of this study was to examine the mechanisms through which an OEA-based dietary supplement (OEA-DS) exerts a comprehensive influence on multiple aspects of the pathogenesis of MASLD, thereby demonstrating a robust hepatoprotective effect. Methods: mice were fed a high-fat, high-cholesterol diet with or without OEA-DS supplementation. Liver tissues and blood serum were analyzed for cholesterol levels, inflammatory markers (CD68, Iba-1, CD163, IL-1β, IL-6, TNFα), apoptotic markers (Bad, Bax, Bcl-2), nuclear receptors (PPAR-α, PPAR-γ, AdipoR1), and enzymes involved in lipolysis (Acox1, Cpt1a) and cholesterol metabolism (Ldlr, Furin, Pcsk9). Immunohistochemistry, Western blotting, and RT-PCR were used to assess protein expression and gene transcription. Results: administration of OEA-DS normalized cholesterol levels, decreased expression of inflammatory markers (CD68 and Iba-1), pro-apoptotic markers (Bad, Bax) and levels of pro-inflammatory cytokines (IL-1β, IL-6, TNFα). In parallel, the expression of nuclear receptors PPAR-α and PPAR-γ, adiponectin receptor 1 (AdipoR1), and anti-inflammatory (CD163) and anti-apoptotic (Bcl-2) markers have risen. OEA-DS administration induced the expression of liver lipolysis enzymes (Acox1, Cpt1a) and cholesterol metabolism factors (Ldlr, Furin), while simultaneously reducing the transcription of the proatherogenic factor Pcsk9. Conclusions: The results of this study suggest a complex action of OEA-DS in obesity-associated liver damage, which includes reduction of systemic inflammation.