Zafer Yonden

Protective effects of tadalafil on experimental spinal cord injury in rats

Tadalafil is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). Nitric oxide (NO) functions as a retrograde neurotransmitter in the spinal cord, and postsynaptic structures respond to NO by producing cGMP. The concentrations of cGMP in the spinal cord are controlled by the actions of PDE. The aim of the study was to evaluate and compare the effects of the use of both methylprednisolone and tadalafil on serum and tissue concentrations of NO, malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, and tissue glutathione peroxidase (GSH-Px) activity in rats with spinal cord injury (SCI). SCI was induced in Wistar albino rats by dropping a 10 g rod from a 5.0 cm height at T8-10. The 28 rats were randomly divided into four equal groups: tadalafil, methylprednisolone, non-treatment and sham groups. Rats were neurologically tested at 24 hours after trauma. At the end of the experiment, blood samples were collected and spinal cord tissue samples were harvested for biochemical evaluation. The tissue level of NO was increased in the tadalafil group compared with the non-treatment and methylprednisolone groups (p<0.05). The tissue levels of SOD and GSH-Px did not differ between the groups. Serum levels of NO were higher in the tadalafil group than in the non-treatment group (p<0.05). The increase in serum SOD levels was greater in the tadalafil group than the methylprednisolone group. Serum MDA levels in the tadalafil and methylprednisolone groups tended to be lower than in the non-treatment group (p>0.05). Tissue MDA levels in the tadalafil and methylprednisolone groups tended to be lower than in the non-treatment group and sham groups (p>0.05). Although there was no difference in neurological outcome scores between the tadalafil, methylprednisolone and non-treatment groups (p>0.05), the animals in the tadalafil and methylprednisolone groups tended to have better scores than the non-treatment group. Thus, tadalafil appears to be beneficial in reducing the effects of injury to the spinal cord by increasing tissue levels of NO and serum activity of SOD.

Protective effects of thymoquinone against methotrexate-induced testicular injury

Thymoquinone is the major active component derived from Nigella sativa. Methotrexate is a folic acid antagonist widely used in clinic. Aim of this study was to investigate the possible protective role of thymoquinone on testicular toxicity of methotrexate. Experiments were performed on male C57BL/6 mice (6 weeks old, 20 ± 2 g). The animals were divided into four groups with six mice in each group. Equivalent volumes of saline were injected intraperitoneally (i.p.) in the control group. In the thymoquinone group, mice received thymoquinone i.p. with a dose of 10 mg/kg/day for 4 days. Mice in the methotrexate group received single dose of methotrexate i.p., with a dose of 20 mg/kg. Finally, in the methotrexate plus thymoquinone group, in the first and the following 3 days after methotrexate administration, thymoquinone was injected with a dose of 10 mg/kg/day, i.p. At the end of the experiment, the left testis was quickly removed and divided into two parts for histological examination and biochemical analysis. Methotrexate alone increased total antioxidant capacity and myeloperoxidase activity compared to the controls. Thymoquinone treatment decreased total antioxidant capacity and prevented the increase in the myeloperoxidase activity. Light microscopy showed in mice that receiving methotrexate resulted in interstitial space dilatation, edema, severe disruption of the seminiferous epithelium and reduced diameter of the seminiferous tubules. Administration of thymoquinone reversed histological changes of methotrexate significantly. We suggest that thymoquinone use may decrease the destructive effects of methotrexate on testicular tissue of patients using this agent.

Protective Effects of N-Acetylcysteine on Cyclosporine-A-Induced Nephrotoxicity

Objectives. Cyclosporine A (CsA) is used for the treatment of autoimmune and inflammatory disorders. However, CsA‐induced nephrotoxicity remains an important clinical problem, and oxidative stress has been implicated as a possible responsible mechanism. We assessed the protective ability of N‐acetylcysteine (NAC), an antioxidant, against CsA-induced nephrotoxicity. Materials and Methods. Wistar albino rats were randomly assigned into four groups. Group 1 rats were treated with sodium chloride as control, group 2 with CsA, group 3 with CsA and NAC, and group 4 with NAC alone. Animals were sacrificed and blood samples were analyzed for blood urea nitrogen (BUN), serum creatinine (Cr), malondialdehyde (MDA) and nitric oxide (NO) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. Kidney sections were analyzed for MDA and NO levels and SOD and GSH-Px activities, as well as histopathological changes. Results. Overall, the treatment of rats with CsA alone produced significant increases in NO and MDA levels and significant decreases in SOD and GSH-Px activities in serum and renal samples. Morphological changes, including tubular epithelial atrophy, vacuolizations, and cellular desquamations, were clearly observed in the rats treated with CsA alone. Concurrent NAC administration with CsA improved renal function, as indicated by lower BUN and Cr values. Moreover, NAC significantly reduced MAD and NO levels and increased SOD and GSH-Px activities in serum and renal tissue, as well as provided a histologically proven protection against CsA-induced nephrotoxicity. Conclusion. These results indicate that NAC produces a protective mechanism against CsA-induced nephrotoxicity and suggest a role for oxidative stress in pathogenesis.

Effects of Erdosteine on Acetaminophen-induced Hepatotoxicity in Rats

We investigated the effects of erdosteine on acetaminophen (APAP)-induced hepatotoxicity in rats. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), AST (aspartate aminotransferase), and ALT (alanine transaminase) activities, and malonyldialdehyde (MDA) and nitric oxide levels as oxidant/antioxidant biochemical parameters were investigated with light microscopic evaluation in adult female Wistar Albino rats. APAP administration produced a decrease in hepatic SOD, CAT, and GSH-Px activities, and coadministration of erdosteine (150 and 300 mg/kg) resulted in increases in the activities. MDA and NO levels increased in the APAP group, and erdosteine treatments prevented these increases. Significant elevations in serum AST and ALT levels were observed in the APAP group, and when erdosteine and APAP were coadministered, their serum levels were close to those in the control group. Light microscopic evaluation of livers showed that there were remarkable centrilobular (zone III) hepatic necrosis and mild to moderate sinusoidal congestion in the APAP group, whereas in the erdosteine group, cellular necrosis was minimal and the hepatocytes maintained a better morphology when compared to the APAP group. Erdosteine prevented APAP-induced liver injury and toxic side effects probably through the antioxidant and radical scavenging effects of erdosteine.

Increased amount of visceral fat in patients with psoriasis contributes to metabolic syndrome.

Background: Psoriasis is associated with obesity and metabolic syndrome. Metabolic syndrome is associated with visceral fat accumulation. There is no study on the accumulation of visceral fat in patients with psoriasis. Objective: The aim of this study was to compare the visceral fat accumulation in patients with psoriasis and controls. Subjects and Methods: 46 patients with psoriasis and 46 sex- and age-matched control patients were included in this study. The abdominal fat area [visceral fat area (VFA), subcutaneous fat area (SFA) and total fat area (TFA)] at the level of the umbilicus was evaluated by computed tomography. Results: The mean VFA value and VFA/SFA ratio of the psoriasis patients were significantly higher compared with the control patients (123.4 ± 80.3 vs. 81.2 ± 59.8 cm2 and 0.734 ± 0.593 vs. 0.491 ± 0.336; p = 0.005 and p = 0.017, respectively). Fasting blood sugar levels were also found to be significantly higher in psoriasis patients, compared with the control patients (101.8 ± 43.5 vs. 83.4 ± 9.1 mg/dl; p = 0.005). Multiple linear regression analysis indicated that waist-to-hip ratio, age, body weight, the presence of psoriasis and metabolic syndrome were significantly associated with VFA. Conclusion:Psoriasis patients had a higher amount of VFA, compared with the control patients.

Protective Effect of Thymoquinone in Experimental Testicular Torsion

Objectives: To investigate the protective role of thymoquinone (TQ) on unilateral testicular ischemia-reperfusion (I/R) injury in mice. Materials and Methods: Experiments were performed on male C57BL/6 mice (8 weeks old, 20–25 g). The animals were divided into 3 groups including 6 mice in each group: control (sham), torsion/detorsion (TD) and TD+TQ. Mice, except the sham-operated group, were subjected to left unilateral torsion (720° rotation in the clockwise direction). The experiments were finished after sham operation time for controls, 120 min torsion and 240 min detorsion for the other groups. In the TD+TQ group 10 mg TQ was injected intraperitoneally 30 min before detorsion. Results: In the TD group total oxidative stress (TOS), oxidative stress index (OSI) and malondialdehyde (MDA) levels were higher than in the controls. TQ treatment decreased MDA, TOS and OSI values, but did not affect the total antioxidant capacity and myeloperoxidase activity in the TD+TQ group. Upon histological examination, mice in the TD group displayed moderate-to-severe disruption of the seminiferous epithelium. Treatment with TQ resulted in significantly reduced histological damage associated with I/R injury. Conclusion: Our results suggested that TQ treatment may have a protective effect on testicular I/R injury.

Protective effect of caffeic acid phenethyl ester on cyclosporine A-induced nephrotoxicity in rats.

Introduction. Cyclosporine A, an immunosuppressive agent, is widely used after organ transplantation such as the liver and kidney. However, its widespread use is restricted because it has serious toxic effects on the kidney. Caffeic acid phenethyl ester (CAPE) is a natural product with potent anti-inflammatory, antitumor, and antioxidant activities, and it attenuates inflammation and lipid peroxidation induced by ischemia-reperfusion injury. The purpose of the present study was to investigate the effects of CAPE on cyclosporine A (CsA)-induced nephrotoxicity. Material and Methods. Rats were divided into four groups and treated with saline, CAPE, CsA, and CsA + CAPE. Control rats were given saline; the CAPE group was given CAPE (10 μmol/kg/day) for 11 days intraperitoneally; the CsA group was given CsA (15 mg/kg/day) for 10 days subcutaneously; and the CsA+CAPE group was given CAPE for 11 days, and rats were s.c. injected with CsA in 0.5 ml of saline once a day for 10 days at the same time. Results. The administration of CsA alone resulted in higher myeloperoxidase (MPO) activity, lipid peroxidation, superoxide dismutase (SOD), and catalase (CAT) than in the control. The enzyme activities except CAT in rats treated with CAPE alone were not changed. CAPE treatment prevented the increase in malondialdehyde (MDA) and increased CAT activity more, but did not affect the activities of MPO and SOD enzymes. Discussion. CsA causes renal injury and CAPE prevents CAT- and lipid peroxidation-mediated nephrotoxicity via inhibition of oxidative process.

Gradual detorsion of torsioned rat testis attenuates ischemia reperfusion injury

AIM This study was designed to investigate effect of gradual detorsion on testicular ischemia reperfusion injury. MATERIALS AND METHODS A total of 21 male rats were divided into 3 groups, each containing 7 rats. Torsion was created by rotating the left testis 720 degrees in a clockwise direction. Group 1 underwent sham operation. Group 2 (sudden detorsion) served as a torsion/detorsion group, receiving 2 hours torsion and 2 hours detorsion. In group 3, 360 degrees detorsion was done for 20 minutes after 720 degrees torsion for 2 hours. Then, testis was done full detorsion for 100 minutes. At the end of the experiments (fourth hour), left orchiectomy was performed to measure the tissue levels of malondialdehyde (MDA), superoxide dismutase, and glutathione peroxidase and to perform histologic examination in testes. RESULTS The MDA levels of testis tissues were significantly increased in the sudden detorsion group as compared with the sham group. We found decrease of the MDA level in gradual detorsion group, but it was not a statistically significant amount. Significant decrease was found in the superoxide dismutase and glutathione peroxidase activities in the sudden detorsion group as compared with the sham and gradual detorsion groups. Histologic examinations were in accordance with the testicular tissue MDA levels. CONCLUSION In the light of our biochemical and histopathologic findings, we can say that gradual detorsion has a trend to decrease the degree of testicular reperfusion injury in the rat torsion/detorsion model.

Direct and indirect effects of kisspeptin on liver oxidant and antioxidant systems in young male rats

Kisspeptin is a recently discovered hypothalamic peptide which plays an important role in the central control of reproductive functions. We have investigated direct and indirect effects of kisspeptin on the liver oxidative stress in young male rats. Twenty‐four rats were divided into four groups (n = 6/group). First group served as control and received saline. Kisspeptin‐10 was administered to the animals in the second group (20 nmol/rat/day), for a period of 7 days. Rats were given only one dose gosereline (0.9 mg/rat), a GnRH agonist in the third group. The last group received kisspeptin‐10 with gosereline. The activities of catalase, superoxide dismutase (SOD), xanthine oxidase (XO), adenosine deaminase (AD) and level of malondialdehyde were studied in liver tissue. Serum samples were separated for total antioxidant capacity (TAC), total oxidant status (TOS), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, blood urea nitrogen (BUN), colesterol, high‐density lipoprotein (HDL) and triglyceride. Kisspeptin increased the activities of SOD and catalase (p < 0.05). When compared to the control group, the levels of malondialdehyde, TOS and AST were lower, but levels of BUN, cholesterole, HDL and AD were higher in the other three groups (p < 0.05). In conclusion, our findings suggest that kisspeptin may have antioxidant and thus protective effects on the liver tissue. Copyright

NMDA RECEPTOR SUBUNITS 2A AND 2B DECREASE AND LIPID PEROXIDATION INCREASE IN THE HIPPOCAMPUS OF STREPTOZOTOCIN-DIABETIC RATS: EFFECTS OF INSULIN AND GLICLAZIDE TREATMENTS

Recent studies indicate that diabetes mellitus changes N-methyl-D-aspartate (NMDA) receptor subunit composition and impairs cognitive functions. It also has been known that diabetes mellitus causes lipid peroxidation. This study examined the effects of streptozotocin-diabetes and insulin or gliclazide treatment on the hippocampal NMDA receptor subunit 2A and 2B (NR2A and NR2B) concentrations. In addition, malondial--dehyde (MDA) levels were measured as a marker for lipid peroxidation. Eight weeks after the induction of diabetes MDA, levels were increased, and NR2A and NR2B concentrations were reduced. Insulin and gliclazide treatment partially prevented the reduction of NR2A and NR2B expression and prevented the elevation of MDA levels. There was no significant difference between the effects of insulin and gliclazide. The results suggest that the elevation of lipid peroxidation can be the primary biochemical disturbances in diabetes progression, and that changes in NMDA receptor subunit compositions can be involved in cognitive decline in diabetes