Yasin Bayir

Comparative study on the gastroprotective potential of some antidepressants in indomethacin-induced ulcer in rats

Clinical studies have shown that anxiolytic and antidepressant drug therapy benefits patients with ulcers. Many antidepressant drugs have been shown experimentally to produce antiulcer activity in various ulcer models. This study investigated the antiulcer activities of tianeptine, trazodone, and venlafaxine on indomethacin-induced ulcers in rats; and evaluated tianeptines effects on oxidant and antioxidant parameters in rat stomach tissue. The results show that trazodone and venlafaxine did not prevent indomethacin-induced ulcers. Tianeptine, however, decreased indomethacin-induced ulcers significantly at all doses used (6, 12, and 25 mg/kg). Famotidine, an H(2) receptor blocker, showed the highest antiulcer activity. Tianeptine significantly prevented the decrease in glutathione (GSH) content that occurred in the indomethacin-only groups damaged stomach tissues. All doses of tianeptine, but especially the 25 mg/kg dose, significantly decreased catalase (CAT) activity in stomach tissue, compared to the control. All doses of tianeptine eliminated the decrease in superoxide dismutase (SOD) activity in the stomach tissue of rats given indomethacin. Although all doses of tianeptine significantly decreased the malondialdehyde (MDA) content, all doses of tianeptine, except 6 mg/kg, decreased myeloperoxidase (MPO) activities significantly compared to the control. Our results indicate that activating enzymatic and non-enzymatic antioxidant mechanisms and inhibiting some toxic oxidant mechanisms play a role in tianeptines antiulcer effect mechanism.

Anti-inflammatory and antiulcerogenic effects of the aqueous extract of Lobaria pulmonaria (L.) Hoffm.

An aqeuous extract of Lobaria pulmonaria (L.) Hoffm., from which a tea is prepared and consumed as treatment for various diseases in northeastern Turkey, was tested for its anti-inflammatory and antiulcerogenic effects in rats. The carrageenan-induced paw edema, cotton pellet granuloma and indomethacin-induced gastric damage models were used to determine these effects. The extract exhibited moderate anti-inflammatory and strong antiulcerogenic activities.

Protective effects of lithium: a new look at an old drug with potential antioxidative and anti-inflammatory effects in an animal model of sepsis.

Sepsis is the systemic response of an organism against microorganisms and toxins. Lithium is a therapeutic agent used for bipolar disorder and neurodegenerative disease, and it exerts pleiotropic effects on various cellular processes. The present study aimed to determine the effect of lithium on cecal ligation and puncture (CLP)-induced tissue injury in the lungs, by inhibiting the pro-inflammatory cytokine response, and the generation of reactive oxygen species (ROS) triggered by polymicrobial sepsis. Five groups of 20 rats each were used: 1) sham-operated control group; 2) CLP group; 3) 50mg/kg lithium-treated control healthy group; 4) 25 mg/kg lithium-treated CLP group; and 5) 50 mg/kg lithium-treated CLP group. A CLP polymicrobial sepsis model was applied to the rats. All rat groups were killed 16 h later, and lung and blood samples were analyzed histopathologically and biochemically. The 25 and 50 mg/kg of lithium decreased the level of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and the tumor necrosis factor-α (TNF-α) in the serum, and the 8-iso-prostaglandin F2α (8-ISO) level in lung tissue. The lithium also increased the activity of superoxide dismutase (SOD) and the total levels of glutathione (GSH) in the lung tissues of rats. The histopathological scores and examinations were in accordance with the biochemical results, and revealed significant differences in the inflammation scores between the sepsis group and the other groups. The CLP+lithium 50mg/kg group had the lowest inflammation score among the CLP groups. Our results indicated that the therapeutic administration of lithium prevented oxidative stress changes and cytokine changes, and also protected vital tissues.

The Effects of Diabetes and/or Polymicrobial Sepsis on the Status of Antioxidant Enzymes and Pro-Inflammatory Cytokines on Heart, Liver, and Lung of Ovariectomized Rats

BACKGROUND The rat sepsis model in the present study was used to understand the role of sustained hyperglycemia and ovariectomy, either separately or together, on the response of pro-inflammatory mediators and oxidative response. MATERIALS AND METHODS Polymicrobial sepsis was induced using cecal ligation and two-hole puncture. Diabetes was induced in the female Wistar albino rats using intraperitoneal administration of aqueous alloxan monohydrate at a single dose of 150 mg/kg body weight. The rats were divided into five groups: sham control: group 1, ovariectomy: group 2, ovariectomy + sepsis: group 3, ovariectomy + diabetes: group 4, and ovariectomy + diabetes + sepsis: group 5. RESULTS In lung, heart, and liver tissues, the levels of myeloperoxidase (MPO) and lipid peroxidation (LPO) were higher for the groups 3, 4, and 5 than in control group. In heart and liver tissues, superoxide dismutase (SOD) and catalase (CAT) activities were higher for the groups 3, 4, and 5 than control group. In lung tissue SOD activities were higher for the groups 3, 4, and 5 than in control group. Diabetes + ovariectomy caused a significant increase in serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) in comparison to the sham group. The strongest production of TNF-α and IL-6 in serum was observed in the group 5. CONCLUSIONS Hyperglycemia and ovariectomy (postmenopausal period) severely increased serum cytokines and oxidant levels with the stages of our sepsis model. The lung tissue was most affected by diabetes and ovariectomy under sepsis conditions. Ovariectomy leading to estrogen deficiency results in general changes in metabolism, which are seen in the liver, lungs, and heart with diabetes under sepsis conditions.

Boron containing poly-(lactide-co-glycolide) (PLGA) scaffolds for bone tissue engineering

Scaffold-based bone defect reconstructions still face many challenges due to their inadequate osteoinductive and osteoconductive properties. Various biocompatible and biodegradable scaffolds, combined with proper cell type and biochemical signal molecules, have attracted significant interest in hard tissue engineering approaches. In the present study, we have evaluated the effects of boron incorporation into poly-(lactide-co-glycolide-acid) (PLGA) scaffolds, with or without rat adipose-derived stem cells (rADSCs), on bone healing in vitro and in vivo. The results revealed that boron containing scaffolds increased in vitro proliferation, attachment and calcium mineralization of rADSCs. In addition, boron containing scaffold application resulted in increased bone regeneration by enhancing osteocalcin, VEGF and collagen type I protein levels in a femur defect model. Bone mineralization density (BMD) and computed tomography (CT) analysis proved that boron incorporated scaffold administration increased the healing rate of bone defects. Transplanting stem cells into boron containing scaffolds was found to further improve bone-related outcomes compared to control groups. Additional studies are highly warranted for the investigation of the mechanical properties of these scaffolds in order to address their potential use in clinics. The study proposes that boron serves as a promising innovative approach in manufacturing scaffold systems for functional bone tissue engineering.

Nigella Sativa Reduces Tissue Damage in Rat Ovaries Subjected to Torsion and Detorsion: Oxidative Stress, Proinflammatory Response and Histopathological Evaluation

Background: To evaluate biochemically and histopathologically the effects of Nigella sativa (NS) in experimental ischemia and ischemia/reperfusion (I/R) injury in rat ovaries. Methods: Thirty-six female rats were divided into 6 groups: group I = sham operation; group II = 500 mg/kg NS + sham operation; group III = bilateral ovarian ischemia; group IV = 500 mg/kg NS + ischemia; group V = 3-hour period of ischemia + 3-hour reperfusion, and group VI: 3-hour period of ischemia + 500 mg/kg NS 2.5 h after the induction of ischemia + 3-hour reperfusion. At the end of ischemia, the bilateral vascular clips were removed, and 3-hour reperfusion was continued. IL-1β, IL-6, and TNF-α cytokine levels in serum, and superoxide dismutase (SOD), myeloperoxidase (MPO), glutathione (GSH), and malondialdehyde (MDA) levels were determined. Results: I/R increased the MDA level and MPO activity while significantly decreasing the SOD activity and GSH level when compared to the sham. The 500-mg/kg dose of NS before I/R reversed the trend in MDA levels, MPO activity, SOD activity, and GSH levels. Ischemia and I/R increased the serum levels of IL-1β, IL-6, and TNF-α, while the administration of NS decreased the serum levels of these cytokines. Conclusions: The administration of NS is effective in reversing tissue damage induced by ischemia and/or I/R in ovaries.

The effects of methanol extract of Lobaria pulmonaria, a lichen species, on indometacin-induced gastric mucosal damage, oxidative stress and neutrophil infiltration

Lobaria pulmonaria, a lichen species, has been used in traditional medicine for the treatment of various diseases. This study was designed to determine the gastroprotective effect of the methanol extract of L. pulmonaria in an indometacin‐induced ulcer model in rats. The results showed that gastric lesions were significantly reduced in a dose‐dependent manner. Furthermore, the administration of indometacin caused a significant decrease in the levels of superoxide, glutathione peroxidase and reduced glutathione and an increase in the lipid peroxidation level. Administration of the lichen extract, however, produced an increase in the levels of these enzymes and a decrease in lipid peroxidation levels, although catalase and myeloperoxidase levels were unaffected. The present results suggested that Lobaria pulmonaria has a gastroprotective effect, probably due to reducing oxidative stress and neutrophil infiltration. Copyright

Inflammation and peripheral 5-HT7 receptors: The role of 5-HT7 receptors in carrageenan induced inflammation in rats

The aim of this study was: (1) to investigate possible role for 5-HT7 receptors in carrageenan induced inflammatory paw oedema in rats; (2) to determine the presence of 5-HT7 receptors in rat paw tissue; (3) to observe the effects of 5-HT7 receptor agonist and antagonist administration on inflammation; and (4) to determine a unique mechanism for inflammatory processes via 5-HT7 receptors. Effects of 5-HT7 receptor agonist, antagonist and indomethacin were investigated in carrageenan induced paw oedema in rats. Blood and tissue samples were collected and evaluated biochemically for serum cytokine levels, tissue oxidant-antioxidant balance and histopathologically for inflammatory cell accumulation. We performed Real Time PCR analyses for tissue 5-HT7 receptor and COX mRNA expressions. The 5-HT7 receptor agonist AS-19 exerted significant anti-inflammatory effect both alone and in combination with indomethacin. Antagonist, SB269970, did not affect inflammation alone but decreased the effects of agonist when co-administered. 5-HT7 mRNA levels were higher in the carrageenan group than healthy control. Carrageenan+indometacin group decreased the mRNA expression of 5-HT7 when compared to carrageenan group. While agonist administration decreased 5-HT7 mRNA expression when compared to carrageenan group. Agonist decreased paw COX expression. Agonist also decreased serum cytokine levels and tissue oxidative stress. In conclusion, this study demonstrated for the first time that 5-HT7 receptors are expressed in rat paw tissue and that this expression responds to inflammatory stimuli. The 5-HT7 receptor may be a promising new therapeutic target for prevention of inflammation and inflammatory disorders and may also provide a new glimpse into inflammation pathophysiology.

The effects of polymicrobial sepsis with diabetes mellitus on kidney tissues in ovariectomized rats

Objectives: Sepsis model was used to understand the role of sustained hyperglycemia and ovariectomy, either separately or concomitantly, on the response of the activity of the nuclear factor kappa B (NF-κB) and the oxidative response in kidney. Subjects: Polymicrobial sepsis was induced by cecal ligation and puncture (CLP). Diabetes was induced in female rats using administration of alloxan. The rats were divided into five groups: sham control (group 1), ovariectomy (group 2), ovariectomy + sepsis (group 3), ovariectomy + diabetes (group 4), and ovariectomy + diabetic + sepsis (group 5). Results: In kidney tissues, the levels of lipid peroxidation (LPO) and glutathione (GSH) and the activity of catalase (CAT) were higher for groups 3, 4, 5 than the control groups. Superoxide dismutase (SOD) activity was lower for groups 3, 4, 5 than the control groups. We determined that CLP produced injury evident in the kidneys of rats when compared to the control group, whereas the severity of the injury was higher in the diabetes + ovariectomy + CLP group when compared to the CLP group. In immunohistochemical staining, we determined that CLP operation increased NF-κB activation. In the ovariectomized, septic, and diabetic group, NF-κB activation was significantly higher than other groups. Conclusions: Hyperglycemia and ovariectomy severely increased NF-κB activation and oxidant levels with the stages of our sepsis model. Ovariectomy resulted in general changes in metabolism, which are seen in the kidney with diabetes under sepsis conditions.

The effect of alpha-lipoic acid in ovariectomy and inflammation-mediated osteoporosis on the skeletal status of rat bone

Osteoporosis is a high mortality and morbidity ranged skeletal disease and results in high costs of medical care in the European Union. We evaluated the possible protective effect of alpha-lipoic acid (ALA) on rat bone metabolism in ovariectomy and inflammation-mediated osteoporosis models. Groups were designed as: (1) sham; (2) sham+inflammation; (3) ovariectomy (OVX); (4) ovariectomy+ALA-25mg/kg; (5) ovariectomy+ALA-50mg/kg; (6) ovariectomy+inflammation; (7) ovariectomy+inflammation+ALA-25mg/kg; and (8) ovariectomy+inflammation+ALA-50mg/kg groups. OVX groups were allowed to recover for two months. Then, inflammation was induced in inflammation groups by subcutaneous talc injection. ALA-25mg/kg and 50mg/kg were administered to drug groups chronically. The skeletal response was assessed by bone mineral density (BMD), osteopontin and osteocalcin measurements. Pro-inflammatory cytokine measurements (interleukin (IL)-1 beta, interleukin-6, and tumor necrosis factor-alpha) were performed to observe inflammatory process. In OVX, INF and OVX+INF groups, BMD levels were lowest and osteocalcin, osteopontin, IL-1 beta, IL-6, and TNF-alpha levels were highest when compared to sham group. ALA administration increased BMD levels and decreased osteocalcin, osteopontin, IL-1 beta, IL-6, and TNF-alpha levels versus OVX and OVX+INF control groups. Both in senile and postmenopausal osteoporosis, the balance in coupling were destroyed on behalf of bone resorption. ALA had a protective effect on both senile and postmenopausal osteoporosis. The positive effect of this drug in these osteoporosis models might originate from its positive effects on bone turnover markers and cytokine levels. From this perspective, ALA may be a candidate for radical osteoporosis treatment both in senile and postmenopausal types clinically at the end of advanced studies.