Nihal Cetin

Biochemically and histopathologically comparative review of thiamine's and thiamine pyrophosphate's oxidative stress effects generated with methotrexate in rat liver

Summary Background Oxidative liver injury occurring with methotrexate restricts its use in the desired dose. Therefore, whether or not thiamine and thiamine pyrophosphate, whose antioxidant activity is known, have protective effects on oxidative liver injury generated with methotrexate was comparatively researched in rats using biochemical and histopathological approaches. Material/Methods Thiamine pyrophosphate+methotrexate, thiamine+methotrexate, and methotrexate were injected intraperitoneally in rats for 7 days. After this period, all animals’ livers were excised, killing them with high-dose anesthesia, and histopathologic and biochemical investigations were made. Result Biochemical results demonstrated a significant elevation in level of oxidant parameters such as MDA and MPO, and a reduction in antioxidant parameters such as GSH and SOD in the liver tissue of the methotrexate group. Also, the quantity of 8-OHdG/dG, a DNA injury product, was higher in the methotrexate group with high oxidant levels and low antioxidant levels, and the quantity of 8-OHdG/dG was in the thiamine pyrophosphate group with low oxidant levels and high antioxidant levels. In the thiamine and control groups, the 8-OHdG/dG rate was 1.48±0.35 pmol/L (P>0.05) and 0.55±0.1 pmol/L (P<0.0001). Thiamine pyrophosphate significantly decreased blood AST, ALT and LDH, but methotrexate and thiamine did not decrease the blood levels of AST, ALT and LDH. Histopathologically, although centrilobular necrosis, apoptotic bodies and inflammation were monitored in the methotrexate group, the findings in the thiamine pyrophosphate group were almost the same as in the control group. Conclusions Thiamine pyrophosphate was found to be effective in methotrexate hepatotoxicity, but thiamine was ineffective.

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 Mirtazapine on Cisplatin-Induced Oxidative Damage and Infertility in Rat Ovaries

Cisplatin causes infertility due to ovarian toxicity. The toxicity mechanism is unknown, but evidence suggests oxidative stress. In this study, the effect of mirtazapine on cisplatin-induced infertility and oxidative stress in rats was investigated. 64 female rats were divided into 4 groups of 16. Except for the controls that received physiologic saline only, all were administered with cisplatin (5 mg/kg i.p.) and mirtazapine (15 mg/kg p.o.) or mirtazapine (30 mg/kg p.o.) for 10 days. After this period, six rats from each group were randomly selected, and malondialdehyde (MDA), myeloperoxidase (MPO), nitric oxide (NO), total gluthatione (tGSH), gluthatione peroxidase (GPx), superoxide dismutase (SOD), and 8-hydroxy-2 deoxyguanine (8-OH Gua) levels were measured in their ovarian tissues. Reproductive functions of the remaining rats were examined for 6 months. The MDA, MPO, NO groups and 8-OH Gua levels were higher in the cisplatin-treated groups than the controls, which was not observed in the mirtazapine and cisplatin groups. GSH, GPx, and SOD levels were reduced by cisplatin, which was prevented by mirtazapine. Cisplatin caused infertility by 70%. The infertility rates were, respectively, 40% and 10% for the 15 and 30 mg/kg mirtazapine administered groups. In conclusion, oxidative stress induced by cisplatin in the rat ovary tissue causes infertility in the female rats. Mirtazapine reverses this in a dose-dependent manner.

An investigation about the inhibition of acute ischemia/reperfusion damage by dexmedetomidine in rat ovarian tissue

Reperfusion has always been “the emergency intervention” to ischemic tissue. For a given period of time, tissue injury due to ischemia and reperfusion is more serious than injury due to ischemia only. Groups were as: Group 1: 25 µg/kg dexmedetomidine + ischemia/reperfusion group. Group 2: 10 mg/kg yohimbine +25 µg/kg dexmedetomidine + ischemia/reperfusion group. Group 3: Ischemia/reperfusion (control) group. Group 4: Healthy rats. Rat ovaries were exposed to a 3-hour ischemia and then reperfusion ensured for 2 hours. After ischemia/reperfusion, total glutathione, malondialdehyde, 8-hydroxyguanine levels and histopathological investigation were studied. The highest total glutathione and the lowest malondialdehyde and DNA damage levels were determined in dexmedetomidine group when compared to control group. The difference between yohimbine + dexmedetomidine and the control group was insignificant. Dexmedetomidine protects the ovarian tissue of the rat from I/R injury. It is hypothesized that this protective effect of dexmedetomidine is mediated by the α-2 adrenergic receptors. Dexmedetomidine could be useful for attenuation of tissue damage after I/R and prevention of I/R-related complications.

Use of thiamine pyrophosphate to prevent infertility developing in rats undergoing unilateral ovariectomy and with ischemia reperfusion induced in the contralateral ovary

OBJECTIVE To investigate whether thiamine pyrophosphate can prevent infertility developing in rats undergoing unilateral ovariectomy and with ischemia reperfusion induced in the contralateral ovary. Biochemical examinations of the ovaries were also performed. STUDY DESIGN Rats were divided into two main groups of three subgroups each. An ischemia reperfusion model was established in the first main group, while surgical unilateral ovariectomy was performed in the second. Thiamine pyrophosphate and melatonin were administered to the subgroups. No additional procedure was performed in the control groups. The rats were then left in laboratory environments and their fertility levels were determined. Malondialdehyde, total glutathione and DNA damage products were measured in those rats from which ovarian tissue was collected. RESULTS The results showed that thiamine pyrophosphate prevented ischemia/reperfusion injury-related infertility, but melatonin did not provide adequate prevention. However, reproduction in healthy animals receiving melatonin began earlier compared to those receiving thiamine pyrophosphate. Melatonin suppressed oxidative stress caused by ischemia/reperfusion in ovarian tissue significantly better than did thiamine pyrophosphate. CONCLUSIONS We think that different mechanisms, in addition to antioxidant activity, are involved in the prevention of reperfusion-associated infertility after ischemia.

The suppression of endogenous adrenalin in the prolongation of ketamine anesthesia

This study investigated whether or not the anesthetic effect of ketamine in rats is dependent on adrenal gland hormones. The study was performed on two main rat groups, intact and adrenalectomized. Rat were divided into subgroups and given appropriate doses of ketamine, metyrapone or metyrosine. Durations of anesthesia in the groups were then recorded. Endogenous catecholamine levels were measured in samples taken from peripheral blood. This experimental results showed that ketamine did not induce anesthesia in intact rats at doses of 15 or 30mg/kg, and that at 60mg/kg anesthesia was established for only 11min. However, ketamine induced significant anesthesia even at a dose of 30mg/kg in animals in which production of endogenous catecholamine (adrenalin, noradrenalin dopamine) was inhibited with metyrosine at a level of 45-47%. Ketamine at 60mg/kg in animals in which endogenous catecholamine was inhibited at a level of 45-47% established anesthesia for 47.6min. However, ketamine at 30 and 60mg/kg induced longer anesthesia in adrenalectomized rats with higher noradrenalin and dopamine levels but suppressed adrenalin production. Adrenalin plays an important role in the control of duration of ketamine anesthesia, while noradrenalin, dopamine and corticosterone have no such function. If endogenous adrenalin is suppressed, ketamine can even provide sufficient anesthesia at a 2-fold lower dose. This makes it possible for ketamine to be used in lengthy surgical procedures.

Controlled reperfusion for different durations in the treatment of ischemia–reperfusion injury of the rat ovary: evaluation of biochemical features, molecular gene expression, and histopathology

High numbers of proinflammatory cells (PMNLs), which are carried by the blood to ischemic tissue during reperfusion, are considered responsible for inducing the inflammatory response that occurs in ischemia-reperfusion (I/R) injury. Our objective was to determine the controlled reperfusion (CR) interval duration (CRID) that would minimize the injury caused by the PMNLs that infiltrate ischemic tissue. Animal groups were divided into the following groups: Sham group, ovarian I/R group (OIR), and ovarian ischemia controlled-reperfusion groups OICR-1, OICR-2, OICR-3, OICR-4, OICR-5, OICR-6, which had their ovarian artery opened and then closed for 10, 8, 6, 4, 2, or 1 s, respectively. The results show that the COX-2 activity and the gene expression decreased while the COX-1 activity and the gene expression were found to be increased in parallel to the shortening of the period in CRID. From the histopathological examinations, the findings of hemorrhage, edema, congested vascular structures, degenerated cells, and migration and adhesion of PMNLs were scaled as follows: Sham group < OICR-6 < OICR-5 < OICR-4 < OICR-3 < OICR-2 < OICR-1. The results from the histopathological assessments were consistent with the molecular and biochemical findings. In conclusion, our findings suggest that increased COX-2 activity plays a role in I/R injury of the rat ovary, and that controlled reperfusion for 3, 2, or 1 s following 2 h of ischemia may attenuate the effects of I/R injury.

Effects of thiamine and thiamine pyrophosphate on epileptic episode model established with caffeine in rats.

This study examines the effect of thiamine (TH) and thiamine pyrophosphate (TPP) on epileptic episode model induced in rats with caffeine. Animals were divided into groups and given TH or TPP at doses of 10, 30 or 50mg/kg intraperitoneally. Subsequently, all animal groups were injected intraperitoneally with caffeine at a dose of 300mg/kg. Time of onset of epileptic episode was recorded, and the latent period was calculated in seconds. At the end of the experiment, tGSH and MDA levels and SOD and MPO enzyme activities in extracted brain tissues were measured. Latent period duration in rats in the control group was 134±3.2s, compared to 144±13.9, 147±14.5 and 169±15.1s, respectively, in the TH10, TH30 and TH50 groups and 184±8.54, 197±9.1, 225±8.37s, respectively, in the TPP10, TPP30 and TPP50 groups. Latent period duration was 236±6.7 in the diazepam group. Oxidant products were significantly lower in the TPP10, TPP30, TPP50 and diazepam groups compared to the control group (P<0.05), while SOD activity and tGSH levels were significantly higher (P<0.05). There was no significant difference between the TH10, TH30, TH50 groups and the control group in terms of oxidant and antioxidant levels (P>0.05). In conclusions, TPP, especially at a dose of 50mg/kg, significantly prolonged the latent period from administration of caffeine to time of episode and prevented oxidative damage.

The Impact of Resveratrol on Oxidative Stress Induced by Methotrexate in Rat Ileum Tissue: Evaluation of Biochemical and Histopathological Features and Analysis of Gene Expression.

Objective: The aim of this study was to assess the impact of resveratrol (RST) on oxidative stress induced by methotrexate in rat ileum tissue. Materials and Methods: Twenty-four rats were divided into 4 groups with 6 in each group. Each rat was orally administered the following every day for 30 days: group 1 (MTXG), methotrexate (MTX; 5 mg/kg); group 2 (RMTXG), MTX (5 mg/kg) plus RST (25 mg/kg/day); group 3 (RSTG), RST alone (25 mg/kg/day), and group 4 (controls), distilled water. After the rats had been sacrified, the ilea were removed for the assessment of malondialdehyde (MDA), total glutathione (tGSH) and glutathione peroxidase (GSH-Px). Gene expression analyses for interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and myeloperoxidase (MPO) were also performed. Hematoxylin and eosin-stained paraffin-embedded sections of the ileum were analyzed under a light microscope and the findings were recorded. Statistical analyses of the data were performed using one-way ANOVA. Results: The administration of MTX in group 1 yielded a higher level of MDA (8.33 ± 2.5 μmol/g protein, p < 0.001) and lower levels of tGSH (0.97 ± 0.29 nmol/g protein) and GSH-Px (5.22 ± 0.35 U/g protein, p < 0.001) compared to the other groups. MTX also increased IL-1β (40.33 ± 5.43 gene expression levels), TNF-α (6.08 ± 0.59) and MPO gene expression (9 ± 1.41) in group 1 compared to the controls (11.33 ± 2.07, 2.15 ± 0.33 and 3.43 ± 0.48, respectively, p < 0.001). The impact of RST on IL-1β, TNF-α and MPO gene expression induced by MTX was observed as a reversal of these findings (p < 0.05). Severe inflammation, damage to the villus epithelium and crypt necrosis was observed histopathologically in the MTXG group, whereas only mild inflammation was seen in the RMTXG group. Conclusion: In this study, ileal damage caused by MTX was inhibited by RST.

Effect of thiamine pyrophosphate on ischemia-reperfusion induced oxidative damage in rat kidney.

Objectives: The biochemical effects of thiamine pyrophosphate on ischemia-reperfusion (IR) induced oxidative damage and DNA mutation in rat kidney tissue were investigated, and compared to thiamine. Materials and Methods: Rats were divided into four groups: Renal ischemia-reperfusion (RIR); thiamine pyrophosphate + RIR (TPRIR); thiamine + RIR (TRIR); and sham group (SG). Results: The results of biochemical experiments have shown that malondialdehyde (MDA) levels in rat kidney tissue after TRIR and TPRIR treatment were 7.2 ± 0.5 (P > 0.05) and 3.3 ± 0.3 (P < 0.0001) μmol/g protein, respectively. The MDA levels in the SG rat kidney tissue and in RIR group were 3.6 ± 0.2 (P < 0.0001) and 7.6 ± 0.6 μmol/g protein, respectively. Total glutathione (tGSH) levels in TRIR, TPRIR, SG, and RIR animal groups were 2.2 ± 0.3 (P > 0.05), 5.8 ± 0.4 (P < 0.0001), 6.2 ± 0.2 (P < 0.0001), and 1.7 ± 0.2 nmol/g protein, respectively. In the TRIR, TPRIR, SG, and RIR animal groups; 8-hydroxyguanine (8-OHGua)/Gua levels, which indicate mutagenic DNA, were 1.75 ± 0.12 (P > 0.05), 0.93 ± 0.1 (P < 0.0001), 0.85 ± 0.08 (P < 0.0001), and 1.93 ± 0.24 pmol/L, respectively. Conclusions: It has been shown that thiamine pyrophosphate prevents increase in mutagenic DNA in IR induced oxidative damage, whereas thiamine does not have this effect.