Beyzagul Polat

Protective effects of amlodipine on ischemia-reperfusion injury of rat ovary: biochemical and histopathologic evaluation

OBJECTIVE To evaluate the effects of telmisartan as an antioxidant and for its tissue protective properties and to study the biochemical and histopathologic changes in experimental ischemia and ischemia/reperfusion injuries in rat ovaries. DESIGN Experimental study. SETTING Experimental surgery laboratory in a university department. ANIMAL(S) Forty-eight female adult rats. INTERVENTION(S) I: sham operation; II: bilateral ovarian ischemia; III: 3 h ischemia + 3 h reperfusion. IV and V: Rats were administered 10 and 20 mg/kg doses of telmisartan, respectively, before 0.5 h of ischemia, and then ovarian ischemia was applied; after 3 h of ischemia, the ovaries were removed. VI and VII: 3 h ovarian ischemia was applied; 2.5 h after the induction of ischemia, rats were administered the same doses of telmisartan; at the end of 3 h of ischemia, the ovaries were removed and a 3 h reperfusion followed. MAIN OUTCOME MEASURE(S) Superoxide dismutase, inducible nitric oxide synthase, and myeloperoxidase activity in rat ovarian tissue; and histopathologic changes in the ovarian tissue of the rats. RESULT(S) Ischemia and ischemia-reperfusion increased the inducible nitric oxide synthase and myeloperoxidase activity while decreasing the super oxide dismutase activity significantly in comparison with the sham group. Before ischemia and ischemia/reperfusion, telmisartan reversed the trend in inducible nitric oxide synthase activities and the level of myeloperoxidase. CONCLUSION(S) telmisartan is effective in reversing tissue damage induced by ischemia/reperfusion in ovaries.

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.

Adaptation of rat gastric tissue against indomethacin toxicity.

Indomethacin is used in the treatment of inflammatory diseases. But the drug toxicity limits its usage. This study investigated whether adaptation occurred after various dosages of repeated (chronic) indomethacin in rats to the gastro-toxic effects of indomethacin. It also examined whether the adaptation was related to oxidant-antioxidant mechanisms and oxidative DNA damage in gastric tissue. To illuminate the adaptation mechanism in the gastric tissue of rats given various dosages of chronic indomethacin, the levels of oxidants and antioxidants (GSH, MDA, NO, SOD and MPO), activities of COX-1 and COX-2 enzymes and oxidative DNA damage (8-OHd Gua/10(5) Gua) were measured. Results were compared to 25-mg/kg single-dose indomethacin group, and the role of oxidant and antioxidant parameters and oxidative DNA damage in the adaptation mechanism was evaluated. The average ulcer areas of gastric tissue of the 0.5-, 1-, 2-, 3-, 4-, and 5-mg/kg dosages of chronic indomethacin given to rats were 19.5+/-3.7, 12.5+/-3.3, 10+/-5.2, 4.5+/-3.6, 8.6+/-2.4, and 9.5+/-2.1mm(2), respectively. This rate was measured as 21.3+/-2.6mm(2) in the single-dose indomethacin group. Consequently, after various dosages of repeated (chronic) indomethacin administration in rats, it was observed that a clear adaptation developed against gastric damage and that gastric damage was reduced. The best adaptation was observed in the gastric tissue of the 3-mg/kg chronic indomethacin group. In parallel with the damage reduction, the oxidant parameters (MDA and MPO) and oxidative DNA damage (8-OHd Gua/10(5) Gua) were reduced, and the antioxidant parameters (GSH, NO and SOD) were increased. There is no relation between COX enzymes and adaptation mechanism. This circumstance shows that not COX-1 and COX-2 enzymes, oxidant and antioxidant parameters may play a role in the adaptation mechanism.

Anti-Inflammatory and Antinociceptive Effects of Salbutamol on Acute and Chronic Models of Inflammation in Rats: Involvement of an Antioxidant Mechanism

The possible role of β-2 adrenergic receptors in modulation of inflammatory and nociceptive conditions suggests that the β-2 adrenergic receptor agonist, salbutamol, may have beneficial anti-inflammatory and analgesic effects. Therefore, in this study, we induced inflammatory and nociceptive responses with carrageenan-induced paw edema or cotton-pellet-induced granuloma models, both of which result in oxidative stress. We hypothesized that salbutamol would prevent inflammatory and nociceptive responses by stimulating β-2 adrenergic receptors and the prevention of generation of ROS during the acute inflammation process in rats. Both doses of salbutamol used in the study (1 and 2 mg/kg) effectively blocked the acute inflammation and inflammatory nociception induced by carrageenan. In the cotton-pellet-induced granuloma test, both doses of salbutamol also significantly decreased the weight of granuloma tissue on the cotton pellets when compared to the control. Anti-inflammatory and analgesic effects of salbutamol were found to be comparable with those of indomethacin. Salbutamol decreased myeloperoxidase (MPO) activity and lipid peroxidation (LPO) level and increased the activity of superoxide dismutase (SOD) and level of glutathione (GSH) during the acute phase of inflammation. In conclusion, salbutamol can decrease acute and chronic inflammation, possibly through the stimulation of β-2 adrenergic receptors. This anti-inflammatory effect may be of significance in asthma treatment, where inflammation also takes part in the etiopathology. This study reveals that salbutamol has significant antioxidative effects, which at least partially explain its anti-inflammatory capabilities. These findings presented here may also shed light on the roles of β-2 adrenergic receptors in inflammatory and hyperalgesic conditions.

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.

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.

Biochemical and histologic study of lethal cisplatin nephrotoxicity prevention by mirtazapine

BACKGROUND Cisplatin is a platinum derivative frequently used in the chemotherapy of different solid tumors. This biochemical and histologic study investigated a possible protective effect of mirtazapine with regard to cisplatin-induced nephrotoxicity in the rat. METHODS The animals were divided into 4 groups: 15 mg/kg mirtazapine + 10 mg/kg cisplatin, 30 mg/kg mirtazapine + 10 mg/kg cisplatin, only 10 mg/kg cisplatin and negative control (healthy) group. During 14 days, the treatment and treated control group took drugs, while the healthy animals were given distilled water on the same schedule. All animals were sacrificed by high-dose anesthesia at the end of the 14 days of treatment; their kidneys were removed and subjected to histologic and biochemical study. RESULTS In both of the doses we used, mirtazapine decreased the levels of malondialdehyde, creatinine, blood urea nitrogen and myeloperoxidase activity when compared to cisplatin group. On the other hand, it increased total glutathione level in all doses. Slight histopathological findings were determined in mirtazapine groups when compared to cisplatin control group. CONCLUSION In the light of our results and literature knowledge, we can conclude that the protective effect of mirtazapine in cisplatin toxicity originates from its own antioxidant activity.

Effect of Mirtazapine on Oxidative Stress Created in Rat Kidneys by Ischemia-Reperfusion

Abstract In this study, the effect of mirtazapine on rat kidneys versus ischemia-reperfusion (IR) damage was biochemically and histopathologically investigated. The results have shown that malondialdehyde (MDA) level of healthy rat group is 15.2 mol/g protein. The level of this substance was measured as 26.7 mol/g in only ischemia group. The MDA levels of IR and mirtazapine + renal ischemia-reperfusion (MRIR) groups were 39 ± 17.6 mol/g protein. While myeloperoxidase activity of healthy rat group was 20.2 u/g, the activities of only ischemia, IR, and MRIR groups were 28, 36.3, and 21 u/g, respectively. The glutathione levels were measured as 17.7, 12.8, 7.5, and 16.2 nmol/g in healthy, only ischemia, IR, and MRIR groups, respectively. Finally, glutathione S-transferase activities of healthy, only ischemia, IR, and MRIR groups were determined as 20, 13.8, 7.1, and 18.3 u/g, respectively. Histopathologically, while hemorrhage in interstitial area was observed in only ischemia group, significant tubular epithelial swelling, necrosis, and cast accumulation were seen in IR group. In MRIR group, only mild tubular epithelial swelling and mild hyaline cast accumulation were observed in kidney tissue. Consequently, it can be said that mirtazapine has a protective effect on IR-induced kidney damage.

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.