The efficacy of tyrosine kinase inhibitor dasatinib on colonic mucosal damage in murine model of colitis

BACKGROUND AND OBJECTIVE

Ulcerative colitis is an inflammatory condition of the colon in the gastrointestinal system. Currently, the most potent medications used for ulcerative colitis produce no response in 20-30% of cases. There is a need for more efficient and reliable medications. Tyrosine kinase inhibitors have shown efficacy in some inflammatory diseases. Although dasatinib, a tyrosine kinase inhibitor, suppresses proinflammatory cytokines in colonic tissue, there are a few cases of hemorrhagic colitis with dasatinib. There is no study investigating the effect of dasatinib on experimental colitis. We aimed to investigate the effect of dasatinib in a colitis model induced with acetic acid in our study.

METHODS

In the study, 24 male Sprague-Dawley rats randomly distributed into 4 groups of 6 rats each as control, dasatinib, colitis and dasatinib+colitis groups. For colitis induction, 4% acetic acid was used. Sacrificing of the rats was performed on the seventh day. Disease activity, morphologic and histological injury, superoxide dismutase, myeloperoxidase and malondialdehyde activity, TNFα and CD3 expression were assessed in colonic tissue.

RESULTS

Apart from malondialdehyde, significant difference in all parameters between the control and colitis groups was determined. Difference between the colitis and colitis+dasatinib groups was not significant in only weight loss and biochemical parameters. Though dasatinib does not fully resolve the changes in colitis, there was significant regression.

CONCLUSIONS

Dasatinib decreased the inflammation in a rodent model of colitis. It may be provide this effect by the suppression of TNFα. Dasatinib may be one of the treatment options for ulcerative colitis.

Efficacy of diffusion-weighted magnetic resonance imaging in the evaluation of extrahepatic cholestasis-related hepatic fibrosis

BACKGROUND/AIM

To investigate the efficacy of diffusion-weighted magnetic resonance imaging (DWI) in the diagnosis and staging of fibrosis induced by experimental bile duct ligation (BDL).

MATERIALS AND METHODS

Twenty-four rats were divided randomly into four groups: control, BDL--3 days, BDL--2 weeks, and BDL--4 weeks. DWI was performed with b-values of 100 and 500 on the rats from control group at day zero, on the rats from the BDL--3 days group at the end of day 3, on the rats from the BDL--2 weeks group at the end of day 14, and on the rats from the BDL--4 weeks at the end of day 28.

RESULTS

When fibrosis scores generated in all groups were evaluated together, a strong negative correlation was detected between fibrosis scores and apparent diffusion coefficient (ADC) values measured using b 100 and b 500. ADC values obtained using b 100 were found to be significantly higher compared to the fibrosis observed in both the BDL--2 weeks and BDL--4 weeks groups (P < 0.003 and P < 0.001, respectively).

CONCLUSION

We think that DWI may be an alternative to liver biopsy for the diagnosis and staging of hepatic fibrosis with underlying extrahepatic cholestasis.

Effects of sphingosylphosphorylcholine against oxidative stress and acute lung ınjury ınduced by pulmonary contusion in rats

BACKGROUND/PURPOSE

The goal of this study was to evaluate effects of exogenous sphingosylphosphorylcholine (SPC) administration on acute lung injury induced by pulmonary contusion in rats.

METHODS

Eight animals were included in each of the following five groups: control, contusion, contusion phosphate-buffered solution (PBS), contusion SPC 2, contusion SPC 10. SPC was administered 3 days at a daily two different doses of 2 μm/ml and 10 μm/ml intraperitoneally. The severity of lung injury was determined by the neutrophil activation and histological and immunohistochemical changes in the lung. Malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH) were determined to evaluate the oxidative status in the lung tissue.

RESULTS

Treatment with 2 μM SPC inhibited the increase in lung MDA and NO levels significantly and also attenuated the depletion of SOD, GPx, and GSH in the lung injury induced by pulmonary contusion. These data were supported by histopathological findings. The inducible nitric oxide synthase (iNOS) positive cells and apoptotic cells in the lung tissue were observed to be reduced with the 2 μM SPC treatment. But, the 10 μM SPC treatment did not provide similar effects.

CONCLUSIONS

In conclusion, these findings suggested that 2 μM SPC can attenuate lung damage in pulmonary contusion by prevention of oxidative stress, inflammatory process and apoptosis. All these findings suggest that low dose SPC may be a promising new therapeutic agent for acute lung injury.

Effects of methylene blue in acute lung injury induced by blunt chest trauma

BACKGROUND

We studied whether methylene blue (MB) treatment blunts chest trauma-induced lung injury in rats.

MATERIAL AND METHODS

Forty male Sprague-Dawley rats, 200-300g, were used. The rats were divided into five groups (n=8): control, early contusion (EC), early contusion + methylene blue (2 mg/kg, EC+MB), late contusion (LC), and late contusion + methylene blue (2 mg/kg, LC+MB).

RESULTS

Histopathological analysis showed increased hemorrhage, alveolar wall thickness, edema, and inflammatory cell infiltrates in the EC and LC rats, which decreased upon MB treatment. Immunohistochemical studies revealed that MB reduced activation of inducible nitric oxide synthase (iNOS) and the number of active terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. A significant increase was observed in the malondialdehyde (MDA) and nitric oxide (NO) levels in the EC group compared to the control group (p<0.05). In addition, a significant decrease was reported in the glutathione (GSH), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels (p<0.01), but no significant difference was observed in the catalase (CAT) levels among the groups. The MDA level was significantly higher in the LC group compared to the control group, whereas the GSH level was significantly lower compared to the control group. The NO level in the EC+MB group was significantly lower when compared to the NO level in the EC group (p<0.05).

CONCLUSION

The present study provides evidence that MB might serve as a therapeutic treatment for blunt chest trauma.

The protective role of melatonin in experimental hypoxic brain damage

BACKGROUND

It is known that oxygen-derived free radicals play an important role in the pathogenesis of brain injury. Melatonin is a powerful scavenger of the oxygen free radicals. In this study, the protective effect of melatonin against the damage inflicted by reactive oxygen species during brain hypoxia was investigated in newborn rats using biochemical parameters.

METHODS

For biochemical analyses, the levels of lipid peroxidation product (malondialdehyde ([MDA]), levels of reduced glutathione (GSH) and the activities of superoxide dismutase (SOD) and catalase (CAT) were estimated.

RESULTS

After the third day of brain hypoxia, the brain levels of MDA increased. Pretreatment of animals with melatonin abolished the rise in MDA induced by hypoxia. GSH concentration did not increase by pretreatment with melatonin. Additionally, the activities of two antioxidative enzymes (SOD and CAT) decreased after the experimental period with melatonin only preventing the change of CAT. The activity of SOD was not influenced by melatonin administration as expected.

CONCLUSION

In this experimental study, exogenously administered melatonin effectively protected against brain injury by oxidative stress. This protective effect of melatonin may be due to its direct scavenger activity and activation of CAT. Thus, melatonin may potentially be useful in the treatment of neurodegenerative conditions that may involve free radical production, such as perinatal hypoxia.

[Diagnostic value of pediatric trauma score in blunt abdominal injuries]

BACKGROUND

It was reported that pediatric trauma score (PTS) is an important tool for the initial assessment of injury severity and could help in the triage of injured children as well. The aim of this study is to investigate the prognostic value of PTS in blunt abdominal traumas.

METHODS

Between 1997 and 2003, children with blunt abdominal trauma who treated in the Department of Pediatric Surgery, Trakya University Medical Faculty were evaluated with retrospective analysis. PTS was designated for each case. Individual morbidity and mortality were correlated with PTS. Data analysis were performed with Mann Whitney U test and ROC curve statistically.

RESULTS

Seventy five patients were included in this study. The mean age of children was 7.5+/-4.2 years (10 months-15 years). Mechanisms of injury were as follows: automobile versus pedestrian 30, falls 18, motor vehicle crashes 14, bicycle accidents 7 and others 6. Forty two abdominal organ injuries were found.. PTS of the patients who had abdominal injuries were different statistically from others (p<0.05). On the ROC curve sensitivity and specificity were found as %74 and %12 respectively in those with PTS scores of 8.

CONCLUSION

PTS was found to be of low sensitivity and specificity for blunt abdominal trauma patients.

Treatment of tracheomalacia with Palmaz stent: a case report

Tracheomalacia is a potentially life-threatening clinical problem. The expandable Palmaz stent can be used for the treatment of tracheomalacia. We describe a female infant with tracheomalacia who showed respiratory distress the day after birth. Tracheomalacia was diagnosed by bronchoscopic examination, computed tomography and bronchography. At 75 days of age, an expandable metallic stent (Palmaz stent) was inserted into the trachea under fluoroscopic control. The patient's respiratory status improved rapidly. Bronchoscopic examination 6 months after the insertion did not show any granulation tissue. However, in bronchoscopic examination carried out two years later, we detected invasion of the Palmaz stent to the trachea and development of granulation tissue. We think that expandable metallic stent placement should be considered in patients who show intractable respiratory symptoms caused by tracheomalacia in the earlier stages of the treatment. But long-term complications of this procedure are crucial.