DSpace Coleção:

Avaliação dos efeitos da minociclina em modelos experimentais de transtorno afetivo bipolar induzidos por anfetamina: avaliação de parâmetros comportamentais, neuroquímicos, computacionais e de viabilidade celular

Thu, 01 Jan 2026 00:00:00 GMT

Título: Avaliação dos efeitos da minociclina em modelos experimentais de transtorno afetivo bipolar induzidos por anfetamina: avaliação de parâmetros comportamentais, neuroquímicos, computacionais e de viabilidade celular Autor(es): Oliveira, João Victor Souza Abstract: Bipolar disorder (BD) is a chronic psychiatric disorder characterized by alternating episodes of mania and depression. Its pathophysiology is multifactorial, involving alterations in monoaminergic neurotransmission, neuroinflammation, and oxidative stress. Despite the availability of mood stabilizers, the therapeutic limitations and adverse effects associated with current treatments highlight the need for novel pharmacological strategies. In this context, minocycline has attracted considerable interest due to its anti-inflammatory, antioxidant, and neuroprotective properties, as well as its high ability to cross the blood-brain barrier, making this antibiotic a promising adjuvant therapeutic agent for the treatment of BD. Therefore, the present study investigated the effects of oral minocycline (50 mg/kg) in experimental models of d-amphetamine-induced mania and amphetamine withdrawal-induced depression in Swiss mice using an integrated methodological approach comprising in vivo, in silico, and in vitro analyses. The effects of minocycline were compared with those of lithium (100 mg/kg) and valproic acid (300 mg/kg). Animals were subjected to the Open Field Test, Splash Test, and Forced Swim Test in both experimental models. In addition, dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels were determined in the prefrontal cortex, and oxidative stress markers were evaluated in the prefrontal cortex and hippocampus. In the mania model, repeated amphetamine administration induced hyperlocomotion and increased dopamine levels in the prefrontal cortex, confirming the induction of a manic-like phenotype. Under these conditions, minocycline reduced both the number of entries into and the time spent in the center zone of the open field and increased reduced glutathione (GSH) levels in the hippocampus, suggesting a neuroprotective effect associated with modulation of oxidative stress. In the amphetamine withdrawal-induced depression model, minocycline significantly increased the number of crossings and the frequency of rearing in the Open Field Test and reduced thiobarbituric acid reactive substances (TBARS) levels in the prefrontal cortex, indicating an antioxidant effect. No significant changes were observed in the Forced Swim Test. In silico analysis demonstrated that minocycline exhibited molecular affinity for JAK1 and JAK2 comparable to that of clinically used reference inhibitors, with binding energies of −7.2 kcal/mol and −9.1 kcal/mol, respectively, suggesting modulation of this signaling pathway as a potential mechanism underlying its neuroprotective effects. In vitro assays showed that both minocycline and valproate displayed a broad range of non-cytotoxic concentrations, whereas amphetamine significantly reduced PC12 cell viability at concentrations of 1000 μM and above. Furthermore, pretreatment with minocycline significantly increased the viability of amphetamine-exposed PC12 cells, demonstrating a protective effect against psychostimulant-induced cytotoxicity. A similar protective effect was also observed with valproic acid. Taken together, these findings demonstrate that minocycline attenuates behavioral, neurochemical, and oxidative alterations in amphetamine-induced experimental models of bipolar disorder and protects PC12 cells against amphetamine-induced cytotoxicity. These results reinforce the potential of minocycline as an adjuvant therapeutic strategy for bipolar disorder and suggest that modulation of signaling pathways involving JAK1 and JAK2 kinases may contribute to its neuroprotective effects. Tipo: Tese

Efeitos neuroprotetores de nanoemulsões de canabidiol e tetrahidrocanabinol em modelos de epilepsia induzida por PTZ: implicações mitocondriais e astrogliais

Thu, 01 Jan 2026 00:00:00 GMT

Título: Efeitos neuroprotetores de nanoemulsões de canabidiol e tetrahidrocanabinol em modelos de epilepsia induzida por PTZ: implicações mitocondriais e astrogliais Autor(es): Girão Júnior, Francisco Josimar Abstract: Epilepsy is a prevalent neurological disorder in which mitochondrial dysfunction and glialactivation play a central role in its pathophysiology. The main phytocannabinoids of Cannabissativa, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), exhibit anticonvulsantproperties; however, their combined mechanisms of action, particularly regardingmitochondrial bioenergetics, oxidative stress, and astroglial modulation, remain poorlyelucidated. Therefore, this study investigated the effects of CBD and THC nanoemulsions,administered alone or in combination, in acute and chronic models of pentylenetetrazol(PTZ)-induced seizures. In the acute protocol, male Swiss mice received oral doses of CBD,THC, or their combinations in nanoemulsion form, and latency to the first generalized seizureand mortality were evaluated. In the chronic protocol, the development of epileptogenesis,cognitive performance, and neurochemical effects were assessed. Behavioral parameters in the chronic model included the novel object recognition test and the Y-maze test to analyzememory and cognitive function. Oxidative stress in the acute model was measured by lipidperoxidation markers (TBARS/MDA), nitrate/nitrite levels, and mitochondrial H₂O₂production. The expressions of GFAP, GAT-1, and Kir4.1 was evaluated by immunohistochemistry as markers of astrogliosis. Mitochondrial function was analyzed byoxygen consumption, respiratory control ratio, ADP/O ratio, and mitochondrial swelling in invitro and ex vivo preparations. The results demonstrated that the CBD/THC combinationsignificantly increased latency to seizures and death in the acute model, in addition to delaying the development of kindling in the chronic model. The nanoemulsions reduced oxidative and nitrosative stress levels and attenuated hippocampal astrogliosis. Significantmodulation of GAT-1 and Kir4.1 expression was observed in the treated groups, suggestingimproved synaptic homeostasis. In vitro and ex vivo assays showed enhanced mitochondrialbioenergetic efficiency. Overall, these findings indicate that the CBD/THC combination exertsa neuroprotective effect mediated by mitochondrial modulation, reduction of oxidative stress, and regulation of astroglial function, although dose-dependent cognitive effects and experimental limitations were observed. Tipo: Tese

Efeito cicatrizante da nanoemulsão de ácido Alfa-lipóico (NanoALA) em cultura de células: determinação do mecanismo de ação

Thu, 01 Jan 2026 00:00:00 GMT

Título: Efeito cicatrizante da nanoemulsão de ácido Alfa-lipóico (NanoALA) em cultura de células: determinação do mecanismo de ação Autor(es): Aquino, Gabriel Angelo de Abstract: Wound healing is a complex biological process that can be impaired by inflammatory imbalances. Alpha-lipoic acid (ALA), due to its antioxidant and anti-inflammatory properties, has been investigated as a therapeutic agent. This study aimed to develop and characterize an ALA-based nanoemulsion (NanoALA) and to evaluate its wound-healing effects in vitro in RAW 264.7, L929, and HaCaT cells. Formulations F1 and F2 exhibited a mean particle size <220 nm, PDI <0.2, zeta potential of approximately −25 mV, and pH ~5.4, remaining stable for up to 90 days. Atomic force microscopy revealed spherical particles with mean sizes of 25.1 nm (F1) and 14.2 nm (F2), and encapsulation efficiencies of 57.19% and 81.20%, respectively. In cytotoxicity assays, both formulations showed concentration-related effects. In RAW 264.7 cells, the IC₅₀ at 24 h was 16.21 µg/mL (F1) and 10.22 µg/mL (F2), with further reduction at 48 h. In L929 cells, no impairment of viability was observed. In HaCaT cells, no cytotoxicity was detected at 24 h, while at 48 h F1 exhibited an IC₅₀ of 46.53 µg/mL, whereas F2 showed no cytotoxic effect. At concentrations of 50 and 100 µg/mL, both NanoALA and blank nanoemulsion increased nitric oxide (NO) levels, whereas free ALA did not alter this parameter and showed no cytotoxicity in any cell line. Based on these findings, NanoALA F1 was selected for subsequent experiments (2.86, 5.72, and 11.44 µg/mL; free ALA: 5 µg/mL). In LPS-stimulated RAW 264.7 cells, NanoALA F1 significantly reduced NO, TNF-α, and IL-1β levels, with a more consistent effect than free ALA. In paracrine models, conditioned medium from NanoALA F1 reduced NO levels, increased TGF-β, and modulated substance P, whereas free ALA exhibited limited effects. Morphological analysis showed that NanoALA F1 attenuated the inflammatory phenotype in RAW 264.7 cells, suggesting a shift from M1 to an M2-like profile, while free ALA showed only partial effects. Morphometric analysis demonstrated that NanoALA F1 reduced inflammatory cell count and restored cell area and circularity, outperforming free ALA. In the scratch assay, NanoALA F1 significantly accelerated monolayer closure, surpassing the effect of free ALA. In conclusion, NanoALA F1 enhances the therapeutic effects of ALA by promoting greater inflammatory modulation, cellular preservation, and re-epithelialization, with efficacy at low concentrations (2.86 µg/mL). Additionally, it exhibits stability at room temperature and superior performance compared to free ALA, representing a promising nanostructured strategy for wound treatment. Tipo: Tese

Desenvolvimento de peptídeo cíclico derivado do ativador do plasminogênio do tipo uroquinase (uPA19-31): inibição do seu receptor (uPAR) e avaliação dos processos relacionados à invasividade

Wed, 01 Jan 2025 00:00:00 GMT

Título: Desenvolvimento de peptídeo cíclico derivado do ativador do plasminogênio do tipo uroquinase (uPA19-31): inibição do seu receptor (uPAR) e avaliação dos processos relacionados à invasividade Autor(es): Brito, Lucas Moreira Abstract: Cancer is considered a complex disease characterized by a set of genetic and/or epigenetic conditions, with disordered and proliferative development of abnormal cells throughout the body, which may lead to metastasis. Thus, alternative therapies based on the development of synthetic inhibitory peptides capable of competing with the Urokinase-type Plasminogen Activator (uPA) for the binding site on its receptor (uPAR) are at an advanced stage of research. This is because inhibiting the formation of the uPA–uPAR complex through these peptides can prevent the dissemination and proliferation of highly invasive tumor cell lines.. Quantum-level computational simulations have been employed in recent years to understand the various binding mechanisms and the physicochemical properties of biological systems. Thus, the application of Molecular Fractionation with Conjugated Caps (MFCC) allows to obtain important results for the development of more specific therapeutic agents regarding their actions in the body. The present work aimed to develop and quantify an inhibitor peptide of the Urokinase-type Plasminogen Activator Receptor (uPAR) and evaluate the synthetic peptide in processes related to invasiveness and metastasis formation. The input data for the simulations were the 2.5 Å resolution structure of the human uPA-uPAR complex (PDB ID: 3BT2), which underwent computational simulations and quantum analyses, with a binding energy of the uPA-uPAR complex of -143.45 kcal/mol. Based on the interaction sequence of uPA19-31, the design of peptides was proposed through in silico mutagenic alterations. Two new cyclic peptides were developed; the test cyclic peptide (Ser19-Lys20-Trp21-Asp22-Arg23-Trp24-Phe25-Asn26-Lys27-Leu28-Trp29-Trp30) presented a binding energy with the receptor of -280.34 kcal/mol, and the control cyclic peptide (Phe19-Trp20-Lys21-Arg22-Leu23-Lys24-Trp25-Trp26-Asn27-Lys28-Trp29-Asp30-Ser31) had a binding energy of -184.10 kcal/mol. The test and control cyclic peptides showed partial action in processes involving metastasis formation (related to invasiveness) in B16F10 tumor cells, such as adhesion, migration, invasion, and expression of Plaur and uPAR – in vitro –, where they presented the following results: Cell Adhesion - The test peptide significantly reduced B16F10 cell adhesion to type I collagen by 18.27%, while the control peptide caused a reduction of 10.06%, suggesting that both interfere with cell adhesion. Cell Migration - Treated with the test peptide, B16F10 cells showed a significant 49.52% inhibition in migration after 24 hours compared to the negative control, whereas the control peptide inhibited about 19.68%. Cell Invasion - The test peptide inhibited B16F10 cell invasion through Matrigel by 73.7%, while the control peptide caused an inhibition of 43.4%, indicating a more pronounced anti-invasive effect of the test peptide. Expression of Plaur and uPAR - PCR analysis revealed a significant increase in Plaur gene expression in cells treated with the test peptide, indicating that this peptide may influence uPAR expression. Thus, the test and control peptides presented fluorescence densities of 6.63% and 11.95%, respectively, while the negative control showed a fluorescence density of 14.68% in B16F10 tumor cells. In conclusion, the synthetic test and control peptides demonstrated participation in the inhibition of processes associated with invasiveness and metastasis formation, where the use of tools such as MFCC and molecular dynamics for the development of synthetic peptides is essential and highly promising. Tipo: Tese