Parlak, Seçil Nazife; Yakut, Seda; Kara, Adem; Demir, Özlem; Şebin, Saime Özbek

Objective(s): Diabetes mellitus (DM) causes oxidative stress, neuroinflammation, and endoplasmic reticulum (ER) dysfunction that contribute to neurodegeneration. This study investigated the effects of 18β-glycyrrhetinic acid-loaded silver nanoparticles (18β-GA-AgNPs) on brain injury in diabetic rats. Materials and Methods: Fifty-six male Wistar rats were divided into eight groups: Sham, 18β-GA, AgNPs, 18β-GA-AgNPs, DM, DM+18β-GA, DM+AgNPs, and DM+18β-GA-AgNPs. Diabetes was induced by alloxan (120 mg/kg, IP), and treatments were administered orally for 14 days. Biochemical markers (MDA, GSH, SOD), histopathology, and expression of ER stress and apoptotic proteins (ATF6, IRE1, Caspase-3, BCL-2, CREB, TNF-α, and IL-1β) were evaluated. Results: The DM group exhibited significant increases in MDA, TNF-α, IL-1β, ATF6, and Caspase-3 with reduced GSH, SOD, and BCL-2, indicating oxidative stress, inflammation, apoptosis, and ER stress. In contrast, IRE1 levels remained unchanged in DM rats but showed a slight elevation in the AgNPs group. Treatment with 18β-GA-AgNPs markedly reduced MDA, TNF-α, IL-1β, ATF6, and Caspase-3, while restoring GSH, SOD, BCL-2, and CREB expression. Histopathological analysis confirmed neuronal apoptosis and perivascular and extracellular space enlargement in DM rats, whereas 18β-GA-AgNPs substantially attenuated these changes. Overall, 18β-GA-AgNPs provided synergistic neuroprotection by suppressing oxidative stress, inflammation, and ER stress while enhancing antioxidant and anti-apoptotic defenses. Conclusion: These findings suggest that 18β-GA-AgNPs may represent a promising therapeutic strategy against diabetes-associated neurodegeneration, although further long-term, ultrastructural, and sex-inclusive studies are warranted.

Taştan, Tuǧba Bal; Akaras, Nurhan; Demir, Özlem; Ugan, Rüstem Anil

Objective(s): In this study, the effects of astaxanthin on liver tissue in rats with polycystic ovary syndrome (PCOS) were evaluated. Materials and Methods: Fifty-four Spraque-Dawley rats were divided into 9 groups: Groups: Control, PCOS, PCOS+Metformin (Met), PCOS+ Astaxanthin (ASX)10, PCOS+ASX20, PCOS+ASX40, PCOS+Met+ASX10, PCOS+Met+ASX20, and PCOS+Met+ASX40. PCOS was induced in female rats by oral administration of letrozole (1 mg/kg) for 21 days. Rats were treated with ASX (10 mg/kg), ASX (20 mg/kg), ASX (40 mg/kg), and metformin (20 mg/kg) for 7 days after PCOS induction. At the end of the experiment, malondialdehyde (MDA) and superoxide dismutase (SOD) levels were measured in the liver tissue. The liver was stained with hematoxylin/eosin for histological examination. Additionally, NF-kB and caspase 3 were analyzed immunohistochemically. Results: A remarkable abnormality was observed in the biochemical and histological parameters in the liver tissue of the PCOS model rats. Astaxanthin dose-dependently normalized the MDA level. Additionally, astaxanthin showed a protective effect by increasing the SOD level and increasing its antioxidant activities. We observed that administration of astaxanthin in addition to metformin applied in the standard was more effective. Caspase 3 and NF-kB immune positivity was lower in the groups given astaxanthin compared with PCOS. Histologically, it was observed that astaxanthin improved the deteriorated liver morphology in the letrozole-induced PCOS group. Conclusion: According to our results, it was observed that astaxanthin had antioxidant, anti-inflammatory and anti-apoptotic effects on PCOS in the treatment groups. Therefore, it was concluded that astaxanthin may have a protective effect against PCOS side effects.