The Protective Effects of Thymosin-ß-4 in a Rat Model of Ischemic Acute Kidney Injury.

BACKGROUND: Despite the progress in the treatment of acute kidney injury (AKI), current curative approaches fail to provide adequate treatment. In this study, we aimed to investigate the possible protective effects of thymosin-ß-4(Tß4) on an ischemic AKI model in rats. METHODS: Rats were randomly assigned into four groups (n = 8/group): The control group (sham-operated), the ischemia-reperfusion (I/R) group; renal ischemia (90 min) by infrarenal abdominal aortic occlusion followed by reperfusion (3 h), the Tß4 + I/R group; treated with Tß4 before I/R, and the I/Tß4/R group; treated with Tß4 just before reperfusion. Besides renal function determination (creatinine (Cr) and blood urea nitrogen (BUN)); histological evaluation was also conducted. Renal tissue caspase-9, matrix metalloproteinase (MMP-9) activities, and hyaluronan levels were measured. Additionally, renal tissue oxidative stress (lipid hydroperoxide, malondialdehyde, superoxide dismutase, glutathione, pro-oxidant-antioxidant balance, ferric reducing antioxidant power, nitric oxide), inflammation (tumor necrosis factor-α, interleukin-1ß, interleukin-6, nuclear factor-κß) were evaluated. RESULTS: I/R increased the level of caspase-9, MMP-9 activity, and hyaluronan (p < 0.001) and these were significantly decreased in both Tß4 groups. Moreover, I/R led to increases in oxidative stress and inflammation parameters (p < 0.001) while the levels of antioxidants were decreased. Nevertheless, Tß4 in both groups were able to restore oxidative stress and inflammation parameters. Furthermore, Tß4 attenuated histologic injury caused by I/R (p < 0.01) and diminished serum urea-creatinine levels (p < 0.001). CONCLUSION: These results suggest that Tß4 has significant improving effects in ischemic acute kidney injury. This beneficial effect might be a result of the inhibition of extracellular matrix remodeling and apoptosis cascade via modulation in renal redox status and inflammation.

Protective Effect of Thymosin ß4 against Abdominal Aortic Ischemia-Reperfusion-Induced Acute Lung Injury in Rats.

Background and objectives: Ischemia-reperfusion (IR) caused by infrarenal abdominal aorta cross-clamping is an important factor in the development of ischemia-reperfusion injury in various distant organs. Materials and Methods: We investigated potential antioxidant/anti-inflammatory effects of thymosin beta 4 (Tß4) in a rat model of abdominal aortic surgery-induced IR. Tß4 (10 mg/kg, intravenous (i.v.)) was administered to rats with IR (90-min ischemia, 180-min reperfusion) at two different periods. One group received Tß4 1 h before ischemia, and the other received 15 min before the reperfusion period. Results: Results were compared to control and non-Tß4-treated rats with IR. Serum, bronchoalveolar lavage fluid and lung tissue levels of oxidant parameters were higher, while antioxidant levels were lower in the IR group compared to control. IR also increased inflammatory cytokine levels. Tß4 reverted these parameters in both Tß4-treated groups compared to the untreated IR group. Conclusions: Since there is no statistical difference between the prescribed results of both Tß4-treated groups, our study demonstrates that Tß4 reduced lung oxidative stress and inflammation following IR and prevented lung tissue injury regardless of timing of administration.

Remote myocardial injury: the protective role of fluoxetine.

Aortic cross-clamping-induced ischemia-reperfusion (IR) is an important factor in the development of postoperative acute cardiac injury following abdominal aortic surgery. We investigated the possible anti-oxidant/anti-inflammatory effects of fluoxetine (FLX), which is used widely as a preoperative anxiolytic on cardiac injury induced by IR of the infrarenal abdominal aorta. FLX was administered to IR-performed (60 min of ischemia and 120 min of reperfusion) rats for 3 days, once daily at 20 mg/kg i.p. dosage. Results were compared to control and non-FLX-treated IR-performed rats. Serum creatine kinase (CK) and CK-MB levels, lipid hydroperoxide, thiobarbituric acid reactive substances, and pro-oxidant/anti-oxidant balance levels in the IR group were significantly higher whereas superoxide dismutase activity, glutathione, and ferric reducing/anti-oxidant power levels were lower than for the control. IR also increased myeloperoxidase activity, tumor necrosis factor-α, interleukin-1ß, and interleukin-6 and decreased interleukin-10 levels. FLX decreased CK, CK-MB, lipid hydroperoxide, thiobarbituric acid reactive substances, and pro-oxidant/anti-oxidant balance levels while increasing superoxide dismutase activity, glutathione, and ferric reducing/anti-oxidant power levels. FLX also decreased myeloperoxidase activity, tumor necrosis factor-α, interleukin-1ß, and interleukin-6 levels and increased interleukin-10 levels compared to IR. FLX attenuated the morphological changes associated with cardiac injury. Our study clearly demonstrates that FLX confers protection against aortic IR-induced cardiac injury, tissue leucocyte infiltration, and cellular integrity via its anti-oxidant/anti-inflammatory effects.

The effects of fluoxetine on circulating oxidative damage parameters in rats exposed to aortic ischemia-reperfusion.

Oxidative stress and reperfusion injury may develop in different ischemia-reperfusion (IR) models. Growing evidence links altered lipid protein redox-homeostasis with IR. The effect of fluoxetine (FLX; N-methyl-3-[4-(trifluoromethyl) phenoxy] benzenepropanamine), on the lipid protein redox-homeostasis mechanisms in the rats exposed to aortic IR is unclear. We aimed to investigate the effects of FLX on circulating protein oxidation and lipid peroxidation parameters, such as ischemia modified albumin (IMA), lipid hydroperoxide (LOOH), prooxidant antioxidant balance (PAB), erythrocyte glutathione (GSH), CuZn-superoxide dismutase (CuZn-SOD), ferric reducing antioxidant power (FRAP), as potential IR biomarkers. Wistar rats were randomized into three groups (n=7/group): 1) Control (sham laparotomy); 2) IR without FLX, (60min ischemia and 120min reperfusion); 3) IR with FLX (FLX+IR) (FLX 20mg/kg/day, i.p. for three days before surgery). All of the aforementioned parameters (IMA, LOOH, PAB, GSH, CuZn-SOD, and FRAP) were measured spectrophotometrically. IMA, LOOH, and PAB levels in IR group were significantly higher than the control (P<0.01 respectively) and fluoxetine groups (P<0.01, P<0.01, and P<0.05 respectively), whereas CuZn-SOD activities, GSH and FRAP were significantly lower in IR groups. Fluoxetine group significantly reduced IMA when compared to IR group (P<0.001) and control group (P<0.01). With respect to IMA, LOOH and PAB, impaired redox homeostasis is substantially more prominent in aortic IR. The antidepressant FLX has profitable effects on circulating redox status in rats exposed to aortic IR. FLX administration before IR might decrease the surgery-enhanced free radical production; taken together, the antioxidant effects of FLX supplementation should be considered in future studies.

Fluoxetine ameliorates imbalance of redox homeostasis and inflammation in an acute kidney injury model.

Ischemia-reperfusion (IR) has been reported to be associated with augmented reactive oxygen radicals and cytokines. Currently, we aimed to examine the influence of fluoxetine, which is already used as a preoperative anxiolytic, in the context of IR induced by occlusion of infrarenal abdominal aorta (60 min of ischemia) and its effects on renal oxidative status, inflammation, renal function, and cellular integrity in reperfusion (120 min post-ischemia). Male rats were randomly assigned as control, IR, and pretreated groups. The pretreated group animals received fluoxetine (20 mg/kg, i.p.) once daily for 3 days. Renal tissue oxidative stress, myeloperoxidase activity, proinflammatory cytokines (tumor necrosis factor-α, interleukin-1ß, interleukin-6), histology, and function were assessed. As an anti-inflammatory cytokine, interleukin-10 was also assessed. IR led to a significant increase in lipid hydroperoxide, malondialdehyde, and pro-oxidant antioxidant balance and decrease in superoxide dismutase activity and ferric reducing/antioxidant power level (p < 0.05), but fluoxetine was able to restore these parameters. High concentrations of tumor necrosis factor-α, interleukin-1ß, interleukin-6, and myeloperoxidase activity caused by IR were significantly decreased in kidney tissue with fluoxetine. In addition, interleukin-10 levels were high in fluoxetine pretreated group. IR resulted in disrupted cellular integrity, infiltration of tissue with leukocytes, and decreased serum creatinine-urea levels (p < 0.05). Fluoxetine significantly restored impaired redox balance and inflammation parameters of rats subjected to IR to baseline values. This beneficial effect of fluoxetine on redox balance might be addressed to an improvement in renal function.

The effect of fluoxetine on ischemia-reperfusion after aortic surgery in a rat model.

BACKGROUND: Aortic ischemia-reperfusion (IR) is an important factor in the development of postoperative acute lung injury after abdominal aortic surgery. The aim of the present study was to examine the effect of fluoxetine (Flx), a selective serotonin reuptake inhibitor widely used as a preoperative anxiolytic, on lung injury induced by abdominal aortic IR in rats. METHODS: Wistar rats were randomized into three groups (n = 7 per group): (1) control (sham laparotomy); (2) IR without Flx (60-min ischemia and 120-min reperfusion); (3) IR with Flx (Flx + IR) (Flx 20 mg/kg/d, intraperitoneally for 3 d before surgery). Lung tissue samples and bronchoalveolar lavage (BAL) were obtained for biochemical analysis of oxidative status. Ischemia-modified albumin (IMA) level and protein concentrations in BAL and lung wet to dry weight ratios were determined. Histologic evaluation of the lung tissues was also performed. RESULTS: IR without Flx led to significant increase in lipid hydroperoxide, malondialdehyde, and pro-oxidant-antioxidant balance and decrease in superoxide dismutase, glutathione, and ferric reducing antioxidant power activities (P < 0.05 versus control), whereas Flx was able to restore these parameters (P > 0.05 versus control) and decrease IMA level (P < 0.01 versus control) and protein concentration (P < 0.05 versus control) in BAL and wet to dry lung weight ratio. Histologic evaluation showed that Flx attenuated the morphologic changes associated with lung injury. CONCLUSIONS: The results indicate that Flx confers protection against aortic IR-induced lung oxidative stress and cellular integrity. IMA levels in BAL may be used as a follow-up marker for the efficacy of treatment in lung injury.

The effect of chronic long-term intermittent hypobaric hypoxia on bone mineral density in rats: role of nitric oxide.

Intermittent hypoxia is the most common pattern of hypoxic exposure in humans. The effect of chronic long-term intermittent hypobaric hypoxia (CLTIHH) on bone metabolism is not investigated. We examined the effect of CLTIHH on bone metabolism and the role of nitric oxide (NO) in this process. The rats were divided into three groups in this study. The animals in groups I and II have been exposed to CLTIHH. The animals in group II were also treated with nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester. To obtain CLTIHH, rats were placed in a hypobaric chamber (430 mm Hg; 5 h/day, 5 days/week, 5 weeks). The group III (control) rats breathed room air in the same environment. At the begining of the experiments, bone mineral density (BMD) of the animals were measured, and blood samples were collected from the tail vein. After the 5-week CLTIHH period, the same measurements were repeated. Parathyroid hormone, calcium, phosphate, bone alkaline phosphatase (b-ALP), NO, interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha levels were determined. The cytokines, NO levels, and BMD in CLTIHH-induced rats were higher compared with baseline and control values. The cytokines, b-ALP, and BMD increased while NO levels decreased in the group II compared with baseline values. BMD values of group II were lower than group I but higher than control group. Our results suggested that CLTIHH has positive effects on bone density. Intermittent hypoxia protocols may be developed for treatment and prevention of osteopenia and osteoporosis.

The effects of chronic long-term intermittent hypobaric hypoxia on blood rheology parameters.

The effect of chronic long-term intermittent hypobaric hypoxia (CLTIHH) on blood rheology is not completely investigated. We designed this study to determine the effect of CLTIHH on blood rheology parameters. Present study was performed in 16 male Spraque-Dawley rats that divided into CLTIHH and Control groups. To obtain CLTIHH, rats were placed in a hypobaric chamber (430 mmHg; 5 hours/day, 5 days/week, 5 weeks). The control rats stayed in the same environment as the CLTIHH rats but they breathed room air. In the blood samples aspirated from the heart, hematocrit, whole blood viscosity, plasma viscosity, plasma fibrinogen concentration, erythrocyte rigidity index and oxygen delivery index were determined. The whole blood viscosity, plasma viscosity, hematocrit and fibrinogen concentration values in the CLTIHH group were found to be higher than those of the control group. However, no significant difference was found in erythrocyte rigidity index and oxygen delivery index between the groups. Our results suggested that CLTIHH elevated whole blood viscosity by increasing plasma viscosity, fibrinogen concentration and hematocrit value without effecting the erythrocyte deformability. Hence, CLTIHH that may occur in intermittent high altitude exposure and some severe obstructive sleep apnea (OSA) patients may be responsible for hemorheologic changes in those subjects.

Bone metabolism in ovariectomized rats with induced hyperthyroidism: the effect of estrogen replacement.

We aimed to investigate whether or not the estrogen is playing any role in the effect of thyroid hormones on bone metabolism. The rats were divided into five groups. In the first group L-thyroxine-induced hyperthyroid rats were ovariectomized (OVX) while the OVX rats were administered L-thyroxine in the second group. 17beta-Estradiol (E2) was replaced in OVX rats in Group III. L-thyroxine and E2 were simultaneously administered to OVX rats in Group IV. The fifth group received sham operation. Blood samples taken from the tail vein of rats were analyzed for plasma T3, T4, TSH and serum interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)alpha, calcium (Ca), phosphorous (P), parathyroid [corrected] hormone (PTH), alkaline phosphatase (t-ALP), bone-specific alkaline phosphatase (b-ALP) and E2. The levels of cytokines, t-ALP and b-ALP increased but PTH decreased, while there was no change in Ca and P levels in L-thyroxine-administrated rats. However, the levels of cytokines, Ca, P, PTH, t-ALP and b-ALP did not change in L-thyroxine-administered OVX rats. In OVX rats, the cytokines, t-ALP and b-ALP increased while Ca, P remained the same, but PTH decreased. L-thyroxine administration to OVX rats did not change the cytokines, Ca, P, PTH, t-ALP and b-ALP levels. The replacement of E2 in OVX rats decreased the cytokines, t-ALP and b-ALP values, increased PTH levels while there was no change in Ca and P. L-thyroxine and E2 administration to OVX rats increased the cytokines, t-ALP and b-ALP levels and decreased PTH, but Ca and P remained the same. In sham-operated rats, there was no change in all parameters compared to initial values. This study suggests that estrogen may play a role in the effects of thyroid hormones on bone metabolism.