Effects of melatonin on cytokine release and healing of colonic anastomoses in an experimental sepsis model

BACKGROUND

The present objective was to identify effects of early melatonin application on healing of anastomotic wound and inflammation in an experimental sepsis model.

METHODS

A total of 60 Wistar albino rats were divided into 2 groups. Cecal ligation puncture (CLP) and colonic resection anastomosis were performed on both the control group and the melatonin treatment group. Both groups were divided into 3 subgroups consisting of 10 rats each. One subgroup from each group underwent re-laparotomy at the 16th hour, the next on the 3rd day, and the final subgroup on the 7th day. Presently evaluated were effects of melatonin treatment of early sepsis on interleukin-6 (IL-6), interleukin-10 (IL-10), interferon gamma (INF-γ), and C-reactive protein (CRP) levels, as well as burst pressures (BPs), collagen and hydroxyproline (OHP) content of the anastomotic segments, histopathologic healing, immunohistochemical expressions, CD34, and transforming growth factor beta (TGF-ß).

RESULTS

IL-6 and INF-γ levels of the treatment group showed a significant decrease at the 16th hour and an increase on the 3rd and 7th postoperative days. IL-10 levels were significantly higher at the 16th hour and significantly lower on the 3rd and 7th postoperative days in the control group (p<0.001 for each). The treatment group also showed significantly higher capillary permeability, fibroblast proliferation, and collagen deposits (p<0.001 for each). CD34 expression was significantly increased in the treatment group on the 7th postoperative day (p=0.005).

CONCLUSION

Application of melatonin in early sepsis significantly improved colonic anastomotic healing in a rat model.

The protective effect of adrenomedullin on renal injury, in a model of abdominal aorta cross-clamping

Renal injury induced by aortic ischemia-reperfusion (IR) is an important factor in the development of postoperative acute renal failure following abdominal aortic surgery. The aim of this study was to examine the effect of adrenomedullin (AM) on kidney injury induced by infrarenal abdominal aortic IR in rats. Thirty-two Wistar Albino rats were randomized into four groups (eight per group) as follows: Control group, IR group (120-minute ischemia and 120-minute reperfusion), IR + AM group (a bolus intravenously of 0.05 µg/kg/min AM), and control + AM group. At the end of the experiment, blood and kidney tissue specimens were obtained for biochemical analysis. Immunohistological evaluation of the rat kidney tissues was also done. IR significantly increased (p < 0.05 vs control group) and AM significantly decreased (p < 0.05 vs. IR group) all of the biochemical parameters. Immunohistological evaluation showed that AM attenuated morphological changes as apoptosis associated with kidney injury. The results of this study indicate that AM attenuates both biochemically and immunohistopathologically kidney injury induced by aortic IR in rats.

The protective effect of adrenomedullin on renal injury, in a model of abdominal aorta cross-clamping

Renal injury induced by aortic ischemia-reperfusion (IR) is an important factor in the development of postoperative acute renal failure following abdominal aortic surgery. The aim of this study was to examine the effect of adrenomedullin (AM) on kidney injury induced by infrarenal abdominal aortic IR in rats. Thirty-two Wistar Albino rats were randomized into four groups (eight per group) as follows: Control group, IR group (120-minute ischemia and 120-minute reperfusion), IR + AM group (a bolus intravenously of 0.05 µg/kg/min AM), and control + AM group. At the end of the experiment, blood and kidney tissue specimens were obtained for biochemical analysis. Immunohistological evaluation of the rat kidney tissues was also done. IR significantly increased (p < 0.05 vs control group) and AM significantly decreased (p < 0.05 vs. IR group) all of the biochemical parameters. Immunohistological evaluation showed that AM attenuated morphological changes as apoptosis associated with kidney injury. The results of this study indicate that AM attenuates both biochemically and immunohistopathologically kidney injury induced by aortic IR in rats.

The protective effects of Ginkgo biloba extract (EGb-761) on radiation-induced dermatitis: an experimental study

BACKGROUND

Irradiation of the skin induces production of free radicals, resulting in oxidative stress. EGb-761, an extract from the leaves of the Ginkgo biloba tree, has been reported to be an effective exogenous antioxidant based on its free-radical scavenger properties.

AIM

To investigate the protective effect of G. biloba extract (EGb-761) on radiation-induced dermatitis in rats.

METHODS

Forty male Wistar rats were divided equally into four groups: group 1 received sham radiotherapy (RT) without EGb-761, group 2 received sham RT with EGb-761, group 3 received RT without EGb-761, and group 4 received RT with EGb-761. Levels of malondialdehyde (MDA), nitric oxide (NOx) and glutathione (GSH) were measured. Dermatitis was assessed with a semiquantitative dermatitis item score. The intensity of staining and diffusion of expression for proliferating cellular nuclear antigen (PCNA) and transforming growth factor (TGF)-β3 were also evaluated.

RESULTS

The enhanced oxidative stress seen after RT was markedly diminished when EGb-761 was administered with RT; significantly lower mean MDA (P < 0.005) and higher mean GSH (P < 0.001) levels were seen in group 4 compared with group 3. Although there was a decrease in NOx levels, this was not significant. All (100%) of the animals in group 3 developed dermatitis, whereas only 13% of the animals in group 4 did so (P < 0.0001). There was a significant difference between group 1 and group 3 in PCNA and TGF-β3 staining (P < 0.05), whereas no difference was seen between groups 3 and 4; however, the intensity of staining and diffusion of expression were lower in group 4 than in group 3.

CONCLUSIONS

Prophylactic administration of EGb-761 seems to have a protective effect against radiation-induced dermatitis.

Neuroprotective effects of gabapentin on spinal cord ischemia-reperfusion injury in rabbits

Object

Extensive research has been focused on neuroprotection after spinal cord trauma to alleviate the effects of secondary injury. This study aims to investigate the neuroprotective effects of gabapentin in an experimental spinal cord ischemia reperfusion injury.

Methods

Thirty-two adult male New Zealand white rabbits received spinal cord ischemic injury using the aortic occlusion model. Animals were divided into 4 groups (sham, control, low-dose, and high-dose treatment groups; 8 rabbits in each group). High (200 mg/kg) and low (30 mg/kg) doses of gabapentin were administered to the animals in the treatment groups after spinal cord ischemic injury. Neurological status of the animals, ultrastructural findings in injured tissue samples, and levels of tissue injury markers in these 2 groups were compared with findings in the animals that did not receive the ischemic procedure (sham-operated group) and those that received normal saline after administration of ischemia.

Results

Regarding levels of tissue injury marker levels after ischemic injury, animals in the gabapentin-treated groups demonstrated better results than animals in the other groups. The ultrastructural findings and caspase-3 activity were similar. The treatment groups demonstrated better results than the other groups.

Conclusions

Gabapentin demonstrated significant neuroprotection after early phases of ischemic injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.

Adrenomedullin attenuates aortic cross-clamping-induced myocardial injury in rats

BACKGROUND

In this study we investigate the effects of adrenomedullin on myocardial injury after ischemia-reperfusion (I/R) after abdominal aortic surgery.

METHODS

Thirty-two Wistar rats were randomized into 4 groups (n = 8) as follows: control group (sham laparotomy), the aortic I/R group, aortic I/R plus adrenomedullin group (underwent aortic I/R periods, and received a bolus intravenous injection of .05 μg/kg/min adrenomedullin), and the control plus adrenomedullin group.

RESULTS

Biochemical analysis showed that aortic I/R significantly increased (P < .05) the plasma levels of troponin-I and tumor necrosis factor-α, and the myocardial tissue levels of malondialdehyde, superoxide dismutase, catalase, and angiotensin II, whereas aortic I/R plus adrenomedullin significantly decreased these same factors (P < .05). Aortic I/R significantly increased (P < .05) myocardial tissue levels of nitric oxide whereas aortic I/R plus adrenomedullin significantly increased the same factor (P < .05).

CONCLUSIONS

These results indicate that adrenomedullin has protective effects against myocardial injury induced by abdominal aortic I/R in rats.

The study of biochemical and histopathological effects of spirulina in rats with TNBS-induced colitis

OBJECTIVES

To evaluate the beneficial effects of spirulina on the treatment of experimental colitis.

BACKGROUND

Spirulina, a planktonic blue green algae from oascillateriaceae family, has anti-inflammatory, antioxidant, antitumor, anti-viral, and antimicrobial effects, rendering it a natural drug of prophylactic and therapeutic properties. The effects of spirulina on colitis are not known.

METHODS

Wistar rats weighing 200-300 g were used. Experimental colitis was created during anesthesia using the trinitrobenzene sulfonic (TNBS) acid. The rats were randomly divided into the 3 groups. In the group 1 (sham; n = 8), saline was administered via oral gavage 7 days after 1 ml of rectal saline was administered. In the group 2 (experimental colitis + spirulina; n = 8), 2 g/kg spirulina was administered via oral gavage 7 days after the rectal 1 ml TNBS was administered. In group 3 (experimental colitis; n = 8), enema was administered via oral gavage 7 days after the rectal 1 ml TNBS was administered. Eight days after the instigation of TNBS colitis, the rats were sacrificed and blood and tissue samples were taken. Histopathologic and immunohistochemical evaluations were conducted, and malondialdehyde (MDA), advanced oxidation protein products (AOPP), catalase (CAT), total antioxidant status (TAS), and glutathione (GSH) levels were determined.

RESULTS

Inflammation on mucosa and submucosa, hemorrhage, necrosis, cellular infiltration and crypt abscess formation, immunoreactivity and tissue MDA levels were decreased in the experimental colitis + spirulina group when compared to the experimental colitis group (p < 0.05).

CONCLUSION

The results of the present study indicate the beneficial effects of spirulina on TNBS-induced inflammatory bowel disease (Tab. 6, Fig. 10, Ref. 40).

Adrenomedullin attenuates aortic cross-clamping-induced myocardial injury in rats

BACKGROUND

In this study we investigate the effects of adrenomedullin on myocardial injury after ischemia-reperfusion (I/R) after abdominal aortic surgery.

METHODS

Thirty-two Wistar rats were randomized into 4 groups (n = 8) as follows: control group (sham laparotomy), the aortic I/R group, aortic I/R plus adrenomedullin group (underwent aortic I/R periods, and received a bolus intravenous injection of .05 μg/kg/min adrenomedullin), and the control plus adrenomedullin group.

RESULTS

Biochemical analysis showed that aortic I/R significantly increased (P < .05) the plasma levels of troponin-I and tumor necrosis factor-α, and the myocardial tissue levels of malondialdehyde, superoxide dismutase, catalase, and angiotensin II, whereas aortic I/R plus adrenomedullin significantly decreased these same factors (P < .05). Aortic I/R significantly increased (P < .05) myocardial tissue levels of nitric oxide whereas aortic I/R plus adrenomedullin significantly increased the same factor (P < .05).

CONCLUSIONS

These results indicate that adrenomedullin has protective effects against myocardial injury induced by abdominal aortic I/R in rats.

Comparison of cyanoacrylate-assisted arteriotomy closure with conventional closure technique

BACKGROUND

We aimed to compare conventional suture closure of arteriotomy with N-butyl-cyanoacrylate-assisted suture closure.

METHODS

Forty Wistar rats were randomly divided into two groups. Standard arteriotomy was performed to the abdominal aorta through a midline incision. In the first group, arteriotomy was closed by 3 stitches with 45 degrees between each and in the second by two stitches with 0.1 ml (12-12.5 mg) cyanoacrylate. Amount of blood loss, operation time and severity of myointimal hyperplasia by immunohistochemistry on aorta segments were measured on postoperative days 7 and 30.

RESULTS

Mean anastomotic time was 13.5 +/- 1.64 in the first and 13.0 +/- 1.75 min in the second group (p = 0.356). Operation time was 23.45 +/- 3.63 in the control and 21.0 +/- 3.09 min in the second group (p = 0.027). Mean amount of bleeding was 473.75 +/- 260.5 in the first and 327.5 +/- 155.36 microl in the second group (p = 0.037). Intimal thickness on the 7th day was 80.62 +/- 7.92 in the first and 83.24 +/- 3.42 microm in the second group, and on the 30th day was 81.64 +/- 5.11 in the first and 88.77 +/- 11.03 microm in the second group. The early and late intimal thicknesses were similar (p = 0.35 and 0.87, respectively).

CONCLUSION

Reconstruction of arteriotomies with fewer sutures in combination with cyanoacrylate is a safe method associated with less blood loss and shorter operation time. It also does not lead to increased myointimal hyperplasia.

Evaluation of the risk of systemic fat mobilization and fat embolus following liposuction with dry and tumescent technique: an experimental study on rats

BACKGROUND

Clinical studies have revealed that liposuction causes systemic fat mobilization. However, the degree of the risk it causes is not clear. In this study we investigated the risk of systemic fat mobilization and fat embolus in rats following liposuction using dry and tumescent techniques.

METHODS

At the end of the procedures, the rats were sacrificed and specimens were obtained from the lungs, kidneys, liver, brain, and skin. Histological examinations of the specimens were carried out. Liposuction was not performed in the control group (n = 8), but blood and tissue specimens for histological examinations were obtained.

RESULTS

We found signs of fat embolus in both blood specimens and histological examinations of tissue samples in the study groups. However, the results of the examinations were normal in the control group. Although there were no fat particles in the blood before liposuction, blood specimens obtained following the procedures and in the long-term had fat particles.

Caspase-9 expression is increased in endothelial cells of active Behçet's disease patients

BACKGROUND

Behçet's disease is a multisystem disease of unknown etiology. Caspase-9 is responsible for initiating the caspase activation cascade during apoptosis. The aim of this study was to examine caspase-9 expression in both endothelial and perivascular infiltrates of patients with active Behçet's disease.

METHODS

Fifteen patients with active Behçet's disease, attending the First Dermatology Department, Ankara Numune Hospital, Ankara, Turkey between June 2003 and December 2005, were included in the study. Oral biopsy specimens from nine healthy volunteers were taken as the healthy control group, and skin biopsies from 18 psoriasis patients were used as the inflammatory control group. The specimens were examined with caspase-9 primary antibody. Statistical analyses were performed using SPSS 11.5.

RESULTS

The mean caspase-9-positive endothelial cell counts were 7.17 +/- 2.45 in active Behçet's disease, 4.81 +/- 0.76 in healthy controls, and 4.35 +/- 1.34 in inflammatory controls. The difference between Behçet's disease and healthy controls was statistically significant, with increased endothelial staining in active Behçet's disease (P = 0.049). The difference between Behçet's disease and inflammatory controls was also statistically significant; the rate of staining was higher in Behçet's disease (P = 0.006). The mean caspase-9-positive dermal perivascular cell counts were 5.15 +/- 2.32 in Behçet's disease, 3.32 +/- 0.82 in healthy controls, and 5.54 +/- 4.95 in inflammatory controls. These values did not show any statistically significant difference (P = 0.407).

CONCLUSION

Endothelial cells are one of the key cells in Behçet's disease, and our findings support the role of endothelial cells in the etiopathogenesis of Behçet's disease.

Caspase 9 is decreased in psoriatic epidermis

Psoriasis is a proliferative and inflammatory disease of the skin. Caspase 9 is responsible for initiating the caspase activation cascade during apoptosis. Apoptosis is a physiological mechanism of homeostasis and development, and caspases are the executioners of apoptosis. This study reports the immunohistochemical localisation of caspase 9 in psoriatic skin and compares it with that seen in normal, healthy control skin. Skin biopsy specimens of lesions were obtained from 15 patients with plaque type psoriasis vulgaris. The specimens were labelled immunohistochemically for binding of an anti-caspase 9 primary antibody. Biopsies of healthy skin from 10 age-matched and sex-matched healthy control individuals were also analysed. The caspase 9 positive cell fraction was calculated for both epidermal and dermal cells in psoriatic lesions and healthy control skin. Counts of caspase 9 positive cells from the epidermis of psoriatic skin lesions were significantly lower than those seen in healthy skin (p<0.05). The caspase 9 immunolabelled perivascular cell counts in the dermis were not statistically significantly different in psoriatic lesions versus normal skin (p>0.05). Psoriatic epidermis contains little of the apoptotic marker, caspase 9. The results of this study are indicative of decreased apoptosis in psoriatic epidermis, and no change in the perivascular area in psoriatic lesions. These findings support the idea that decreased apoptosis is seen in psoriatic epidermal cells. Greater understanding of the nature of the disease may open new avenues for further therapeutic modalities.

The effect of taurine on renal ischemia/reperfusion injury

Ischemia-reperfusion (I/R) injury is one of the most common causes of renal dysfunction. Taurine is an endogenous antioxidant and a membrane-stabilizing, intracellular, free beta-amino acid. It has been demonstrated to have protective effects against I/R injuries to tissues other than kidney. The aim of this study was to determine whether taurine has a beneficial role in renal I/R injury. Forty Wistar-Albino rats were allocated into four groups as follows: sham, taurine, I/R, and I/R+taurine. Taurine 7.5 mg/kg was given intra-peritoneally to rats in the groups taurine and I/R+taurine. Renal I/R was achieved by occluding the renal arteries bilaterally for 40 min, followed by 6 h of reperfusion. Immediately thereafter, blood was drawn and tissue samples were harvested to measure 1) serum levels of BUN and creatinine; 2) serum and/or tissue levels of malondialdehyde (MDA), glutathione (GSH), glucose 6-phosphate dehydrogenase (G-6PD), 6-phosphogluconate dehydrogenase (6-PGD) and glutathione reductase (GSH-red); 3) renal morphology; and 4) immunohistochemical staining for P-selectin. Taurine administration reduced I/R-induced increases in serum BUN and creatinine, and serum and tissue MDA levels (p<0.05). Additionally, taurine lessened the reductions in serum and tissue glutathione levels secondary to I/R (p<0.05). Taurine also attenuated histopathologic evidence of renal injury, and reduced I/R-induced P-selectin immunoreactivity (p<0.05). Overall, then, taurine administration appears to reduce the injurious effects of I/R on kidney.

[The effects of early intermittent high-dose estrogen treatment on bone structure of ovariectomized rats]

OBJECTIVES

The effects of various estrogen replacement protocols to prevent bone loss following ovariectomy have been the subject of many studies in rats. This study was designed to determine the effects of early intermittent high-dose estrogen replacement therapy, which has hitherto not been studied, on bone structure of ovariectomized rats.

METHODS

Bilateral ovariectomies were performed in 20 female mature non-pregnant Wistar rats. All the animals were randomly assigned to two groups to receive either subcutaneous 17 beta-estradiol (25 mg/kg) or only sesame oil on days 15 and 22 after ovariectomy. Fourteen days after the last injection, the rats were sacrificed and proximal femurs were removed for both light and electron microscopic analyses.

RESULTS

In the light microscopic analysis, control femurs exhibited a marked destruction in the structure of the cancellous bone, whereas estradiol-treated rats had almost normal cancellous bone. Ultrastructural analysis showed degeneration and increased turnover in bone cells of the control femurs, whereas the bone cells and the bone matrix appeared almost normal in the treatment group. A statistically significant increase in serum estrogen levels was found in estradiol-treated rats (580+/-124 pg/ml versus 62+/-16 pg/ml, p<0.001).

CONCLUSION

Intermittent high-dose estrogen treatment prevents cancellous bone loss in the proximal femurs of ovariectomized rats through inhibition of bone turnover and results in significantly increased serum estrogen levels.