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    Asprosin improved neuronal survival by suppressing apoptosis and enhancing the activity of the autophagy pathway in the MCAO model in rats
    (Verduci Editore s.r.l, 2024) Tanbek K.; Yuksel F.; Tekin S.; Tekin C.; Sandal S.
    OBJECTIVE: Cerebral ischemia (CI) is a condition in which metabolic stress increases when blood flow is interrupted in a part of the brain, resulting in oxygen and glucose deprivation. It is known that asprosin (Asp), secreted from adipose tissue during fasting, has an effect on some metabolic processes such as apoptosis, autophagy, and glucose metabolism. This study aimed to explain which of the cell death/survival Asp induces in the CI/reperfusion model. MATERIALS AND METHODS: In the study, 48 male Wistar Albino rats were divided into 6 groups: Sham, CI, Asp+CI, CI+Asp, CI+Asp+3-MA, and Asp+CI+3-MA (n=48). CI was created using the intraluminal filament technique for 60 minutes, autophagy inhibitor 3-MA (15 mg/kg/ day) and Asp (1 µg/kg/day) injections were administered 3 days before or 3 days during reperfusion. Beclin-1, ATG5, ATG7, p62, Bcl-2, Bax, active-caspase-3, and active-caspase-9 protein levels from brain tissues were determined by the Western-Blot method. The infarct area was determined by triphenyl tetrazolium chloride (TTC) staining. The Kruskal-Wallis’ test was used to compare differences between groups. p<0.05 was considered statistically significant. RESULTS: Compared to the Sham group, the increase in ischemic area and the decrease in Beclin-1, ATG-5, ATG-7, Bcl-2, Bax, active-caspase-3 and active-caspase-9 levels in the CI groups are statistically significant (p<0.05). The increase of Beclin-1, ATG-7, Bcl-2, and Bax levels in the Asp groups is statistically significant compared to the CI group (p<0.05). When Asp+CI groups and CI+Asp groups are compared, an increase in Beclin-1 levels in the Asp+CI group and the increase in Bcl-2, Bax, active-caspase-3/9 and ATG-5 levels in the CI+Asp groups are statistically significant (p<0.05). CONCLUSIONS: Asp has protective and therapeutic effects against CI/R damage. While applying Asp before ischemia activates the autophagy pathway more, applying it after ischemia protects the neuronal death/survival balance by activating the apoptosis pathway more. © 2024 Verduci Editore s.r.l. All rights reserved.
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    Effects of glucagon as a neurohormone on the central nervous system and glucose homeostasis
    (Verduci Editore s.r.l, 2024) Tanbek K.; Yilmaz U.; Gul S.; Koç A.; Gul M.; Sandal S.
    OBJECTIVE: This study aimed to elucidate the possible effects of the acute/ long-term infusion of glucagon in the brain as the regulatory role on the endocrine secretions of the pancreas. MATERIALS AND METHODS: Ninety male Wistar albino rats were divided as Control, artificial Cerebrospinal Fluid (aCSF) (120 min), Glucagon (120 min), pancreatic denervation (PD)+aCSF (120 min), PD+Glucagon (120 min), aCSF (7 days), Glucagon (7 days), PD+aCSF (7 days) and PD+Glucagon (7 days). Glucagon and solvent (aCSF) were administered after pancreatic denervation (PD) by Hamilton syringe and osmotic mini pump (1 µg/10 µl/min) in the third ventricle of the brain. RESULTS: Acute intracerebroventricular (icv) administration of glucagon resulted in an elevation of glucagon levels and a concurrent reduction in blood glucose levels. Furthermore, in both the PD+aCSF (7 days) and PD+Glucagon (7 days) groups, there was a notable decrease in propiomelanocortin (POMC) and agouti-related protein (AgRP). Significant changes were observed in feed consumption and body weight, as well as pancreatic glucagon levels, with a simultaneous decrease in insulin levels in the PD (7 days), Glucagon (7 days), and PD+Glucagon (7 days) groups. These alterations were statistically significant when compared to the control group (p<0.05). CONCLUSIONS: The research outcomes established that pancreas-secreted glucagon functions as a neurohormone within the brain, activating central pathways linked to blood glucose regulation. The presence of glucagon led to a decrease in POMC levels. Surprisingly, this reduction in POMC resulted in the suppression of AgRP. Contrary to expectations, the suppression of AgRP led to an increase in food intake rather than a decrease. As already highlighted in the results section, it was emphasized that POMC may play a more significant role than AgRP in influencing feeding behavior. © 2024 Verduci Editore s.r.l. All rights reserved.
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    Investigation of the Effect of Astaxanthin on Autophagy in Renal Ischemia-reperfusion Modeled Rats
    (Galenos Publishing House, 2024) Kisaoglu A.; Kose E.; Yilmaz N.; Tanbek K.; Yildiz A.; Yilmaz U.; Cirik R.H.
    Objective: The aim of this study was to investigate the effect of various astaxanthin (ATX) doses on oxidative damage and autophagy in renal ischemia-reperfusion (I/R) injury-modeled rats. Methods: The rats were divided into five groups: sham group (n=8), I/R (n=8), I/R + 5 mg/kg ATX (n=8), I/R + 10 mg/kg ATX (n=8), and I/R + 25 mg/ kg ATX (n=8) groups. ATX was dissolved in 5 mg/kg, 10 mg/kg, and 25 mg/ kg olive oil for 7 days and administered to the rats in the experimental group. Sham and I/R groups were also administered ATX solution (olive oil) via oral gavage for 7 days. Renal ischemia reperfusion was induced in all rats except the sham group after the last dose was administered on the 7th day. Reperfusion was conducted for 24 hours after 45 minutes of ischemia. Results: Blood samples were collected, and kidney tissue were incised for biochemical and histological analyses. Superoxide dismutase (SOD) and total antioxidant status (TAS) were significantly lower in the I/R group than in the sham group (p<0.05), whereas malondialdehyde (MDA) and total oxidant status (TOS) values were higher (p<0.05). It was determined that SOD and TAS increased and MDA and TOS decreased in the ATX-administration groups compared with the I/R group, independent of the dose (p<0.05). In the 25 mg/kg ATX + I/R group, Beclin-1 and LC3? immunoreactivities were significantly higher than those in the other groups (p<0.05). The lowest p62 immunoreactivity was observed in the 25 mg/kg ATX + I/R group. Conclusions: ATX had a protective effect on kidney function and against oxidative damage. Furthermore, high-dose ATX administration protected kidney tissue via autophagy induction in this study. © 2024 The Author.