Histopathologic changes in the middle ear mucosa after exposure to pepsin and unconjugated bile acid.

OBJECTIVE: An increasing number of studies indicate that pepsin and bile acid cause damage to the ear, nose, and throat structures as a result of extraesophageal reflux. The aim of this study was to evaluate and compare the damaging effect of bile acids and pepsin on the middle ear mucosa. MATERIAL AND METHODS: Twenty-nine healthy rats were included in this study. The animals were divided into 5 groups. A single daily dose of 40 µmol/L chenodeoxycholic acid, 40 µg/mL pepsin, and saline were injected separately into the right middle ear of the rats. On day 30, all rats were decapitated, and formalin-fixed, paraffin-embedded samples of the middle ear both from the control and experimental rats were prepared. A semiquantitative analysis was performed. RESULTS: Inflammatory response was seen in all middle ear mucosa of rats except control group 1. The degree of inflammatory response was higher in the bile acid group when compared with the other groups. Epithelial metaplastic changes with varying number of goblet cells were observed in both the bile acid- and pepsin-injected groups. These metaplastic changes were also higher in the bile acid-induced group than in the pepsin-injected group. CONCLUSIONS: This is the first study on the middle ear mucosal damage of both pepsin and bile acid. Our results demonstrate that bile acids were associated with more extensive mucosal injury at pH 7 in comparison to pepsin in a rat animal model. Inflammatory response and metaplastic changes may play an important role in the etiology of middle ear pathologies.

Neuroprotective effects of Ac.YVAD.cmk on experimental spinal cord injury in rats.

BACKGROUND: Apoptosis as a cell death mechanism is important in numerous diseases, including traumatic SCI. We evaluated the neuroprotective effects of Ac.YVAD.cmk and functional outcomes in a rat SCI model. METHODS: Thirty rats were randomized into 3 groups of 10: sham-operated, trauma only, and trauma plus Ac.YVAD.cmk treatment. Trauma was produced in the thoracic region by a weight-drop technique. Group 3 rats received Ac.YVAD.cmk (1 mg/kg, ip) 1 minute after trauma. The rats were killed at 24 hours and 5 days after injury. Efficacy was evaluated with light microscopy and TUNEL staining. Functional outcomes were assessed with the inclined plane technique and a modified version of the Tarlov grading system. RESULTS: At 24 hours postinjury, the respective mean number of apoptotic cells in groups 1, 2, and 3 were 0, 5.26 +/- 0.19, and 0.97 +/- 0.15. Microscopic examination of group 2 tissues showed widespread hemorrhage, edema, necrosis, and polymorphic nuclear leukocyte infiltration and vascular thrombi. Group 3 tissues revealed similar features, but cavitation and demyelination were less prominent than those in group 2 samples at this period. At 5 days postinjury, the respective mean inclined plane angles in groups 1, 2, and 3 were 65.5 +/- 2.09, 42.00 +/- 2.74, and 52.5 +/- 1.77. Motor grading of animals revealed a similar trend. These differences were statistically significant (P < .05). CONCLUSIONS: Ac.YVAD.cmk inhibited posttraumatic apoptosis in a rat SCI model. This may provide the basis for development of new therapeutic strategies for the treatment of SCI.

Therapeutic efficacy of Ac-DMQD-CHO, a caspase 3 inhibitor, for rat spinal cord injury.

We investigated the therapeutic efficacy of Ac-DMQD-CHO, a caspase-3 inhibitor, and functional recovery in spinal cord injury in a rat model. Thirty rats were randomized into three groups of 10 each. In groups 2 and 3, spinal cord trauma was produced in the thoracic region. Group 3 rats were treated with Ac-DMQD-CHO. Treatment responses were evaluated based on histopathological and TUNEL staining findings at 24 h and 5 days post-injury. Neurologic performance was assessed during and following treatment. Twenty-four hours after injury, light microscopy examination revealed diffuse hemorrhagic necrosis, edema, vascular thrombi, and polymorphonuclear leukocyte infiltration in group 2 and 3 rats, but cavitation and demyelinization were less prominent in group 3. At this time point, treatment of the rats with Ac-DMQD-CHO significantly reduced the number of apoptotic cells. Traumatic injury to the spinal cord causes apoptosis and administration of Ac-DMQD-CHO decreases apoptosis and improves functional outcome.

Therapeutic efficacy of SJA6017, a calpain inhibitor, in rat spinal cord injury.

Apoptosis is an important element of the secondary processes that occur after spinal cord injury. Calpain and caspases are key proteases in apoptotic cell death. We evaluated the neuroprotective effects of SJA6017 (a calpain inhibitor) and measured functional recovery in a rat spinal cord injury model. Thirty Wistar albino rats were divided into three groups of 10 animals each: sham-operated (group 1), trauma control (group 2) and trauma-plus-SJA6017 treatment (group 3). Spinal cord trauma was produced in the thoracic region of the animals. Rats in group 3 received SJA6017 1 min after trauma. Treatment efficacy was evaluated after injury using light microscopy and TUNEL staining. Neurological performance was assessed using an inclined plane and a modified version of the Tarlov's grading scale. Group 2 rats showed moderate trauma with widespread edema, hemorrhage, vascular thrombi and necrosis 24 h after injury. Group 3 rats had significantly reduced tissue injury and apoptosis. Tarlov scores revealed that group 3 rats also had ameliorated recovery of limb function. Our results demonstrate that treatment with SJA6017 reduces apoptotic cell death, preserves spinal cord tissue and improves functional outcome. Treating calpain-induced apoptosis with this agent may be a feasible therapeutic strategy for patients with spinal cord injury.

Tauroursodeoxycholic acid and secondary damage after spinal cord injury in rats.

Greater clinical understanding of the pivotal role of apoptosis in spinal cord injury (SCI) has led to new and innovative apoptosis-based therapies for patients with an SCI. Tauroursodeoxycholic acid (TUDCA) is a biliary acid with antiapoptotic properties. To our knowledge, this is the first study in the English language to evaluate the therapeutic efficacy of TUDCA in an experimental model of SCI. Thirty rats were randomized into three groups (sham-operated, trauma only, and trauma plus TUDCA treatment) of 10 each. In groups 2 and 3, spinal cord trauma was produced at the T8-T10 level via the Allen weight drop technique. Rats in group 3 were treated with TUDCA (200 mg/kg intraperitoneal) 1 min after trauma. The rats were killed either 24 h or 5 days after injury. The neuroprotective effect of TUDCA on injured spinal cord tissue and the effects of that agent on the recovery of hind-limb function were assessed. The efficacy of treatment was evaluated with histopathologic examination and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) analysis. Histopathologic characteristics were analyzed by comparison of hematoxylin-and-eosin stained specimens. Neurologic evaluations were performed 24 h, 3 days, and 5 days after trauma. Hind-limb function was assessed with the inclined plane technique of Rivlin and Tator and the modified version of Tarlov's grading scale. Twenty-four hours after injury, there was a significantly higher number of apoptotic cells in the lesioned spinal cord group than in the sham-operated control group. Treatment of the rats with TUDCA significantly reduced the number of apoptotic cells (4.52+/-0.30 vs. 2.31+/-0.24 in group 2) and the degree of tissue injury. Histopathologic examination showed that group 3 rats had better spinal cord architecture compared with group 2 rats. Five days after injury, the mean inclined plane angles in groups 1, 2, and 3 were 65.50 degrees +/- 2.09, 42.00 degrees +/- 2.74, and 53.50 degrees +/- 1.36. Motor grading of the rats revealed a similar trend. These differences were statistically significant (p<0.05). The mechanism of neuroprotection in the treated rats, although not yet elucidated, may be related to the marked antiapoptotic properties of TUDCA. A therapeutic strategy using TUDCA may eventually lead to effective treatment of SCI without toxic effects in humans.

P53, KI-67, CD117 expression in gastrointestinal and pancreatic neuroendocrine tumours and evaluation of their correlation with clinicopathological and prognostic parameters.

BACKGROUND/AIMS: Gastrointestinal and pancreatic neuroendocrine tumors (GEPNETs) originate from the cells of the endocrine system. Their molecular genetic mechanism of development and progression is complex and remains largely unknown. The purpose of this study was to review the gastrointestinal and pancreatic neuroendocrine tumors and to evaluate p53, Ki-67 and CD 117 expressions with their clinicopathological correlations. MATERIALS AND METHODS: Twenty-one patients were reviewed and classified as having well-differentiated neuroendocrine neoplasm (WDET, Grade I), well-differentiated neuroendocrine carcinoma (WDEC, Grade II) and poorly differentiated neuroendocrine carcinoma (PDEC, Grade III). We performed immunohistochemical tests to characterize the expession of the immunoreactivity for synaptophysin, chromogranin, p53, Ki67 and CD 117. RESULTS: Median age of 21 patients was 43 years. Thirteen (61.9%) patients were male and eight (38.1%) patients were female. Tumors were located in the stomach (38.1%), appendix (38.1%), duodenum (4.8%), ileum (4.8%), colon (9.5%), and pancreas (4.8%). CONCLUSION: There was a statistically significant difference between well-differentiated endocrine neoplasm (Grade I), and well-differentiated endocrine carcinoma (WDEC, Grade II) and PDEC for Ki-67 >20% (p<0.001) (Pearson chi-square test). There was a statistically significant difference between WDET (Grade I), WDEC (Grade II) and PDEC (Grade III) for p53 positivity (p<0.05) (Pearson chi-square test).

Impact of ligating gonadal or adrenal collateral veins with the left renal vein on renal function and histology in right-nephrectomized rats.

BACKGROUND: In cases of trauma to the left renal vein (LRV), its ligation near the inferior vena cava (IVC) is considered, but the consequences are not always good. We investigated the role of collateral venous drainage after ligation of the LRV by studying the renal function and histology after ligation of the LRV near the IVC alone or with ligation of the gonadal or adrenal collaterals, in right-nephrectomized (RN) rats. MATERIAL AND METHODS: Ligation of the LRV near the IVC alone (group 1) or with ligation of the adrenal (group 2) or gonadal (group 3) collaterals was studied in RN Wistar rats (n=18 per group). The renal histopathology (ischemic cortical necrosis) and functional status (urea, creatinine, sodium, and potassium) were compared. RESULTS: In RN rats, the results were better when ligating the LRV near the IVC alone or with the adrenal collaterals [mortality 4/18 (22.2%) and 3/18 (16.7%), respectively] than when ligating the LRV near the IVC plus the gonadal collaterals [mortality 15/18 (83.3%)] (p<0.0001). All early deaths occurred within three days and resulted from serious histopathological (ischemic cortical necrosis) and functional (increased urea, creatinine, and potassium; decreased sodium) renal damage. CONCLUSION: In right-nephrectomized rats, the LRV near the IVC and the adrenal collateral can be ligated, while the gonadal collateral should be preserved.

The effects of N-acetylcysteine on bile duct ligation-induced liver fibrosis in rats.

Stellate cells are activated by free radicals, and synthesize collagen. N-acetylcysteine (NAC) is a precursor of reduced glutathione and a potent scavenger of hydroxyl radicals and has potential antifibrotic effects. We aimed to test the effects of NAC on bile duct ligation (BDL) induced liver damage in rats. Forty-seven Wistar rats were divided into 5 groups: group 1, BDL+NAC (n=10); group 2, BDL (n=10); group 3, sham+NAC (n=10); group 4, sham (n=10); and group 5, control group (n=10). NAC (50 micromol/kg per day) or saline of single doses were administered intraperitoneally for 28 days. Serum biochemical and liver oxidative stress parameters were studied. Liver collagen level was determined by the method of Lopez de Leon and Rojkind. Liver slides were stained by hematoxylin and eosin and Masson trichrome\Gomory reticulum staining. Aspartate aminotransferase (AST) and alkaline phosphatase levels in the BDL+NAC group were lower than the BDL group and were higher than the control groups (all P< .001). Malondialdehyde, luminal, and glutathione levels in group 1 were lower than the BDL group (P= .01, P= .002, and P< .001) and higher than the control groups (all P< .001). NAC had no effect on alanine aminotransferase (ALT), gammaglutamyl transferase, bilirubin, albumin, or lucigenin levels. Liver collagen levels were higher in the BDL groups (P< .001); however, NAC had no effect on the collagen levels. The BDL groups showed stage 3 fibrosis; all the control groups were normal. NAC improved some biochemical parameters (AST, alkaline phosphatase) and oxidative stress parameters (malondialdehyde, luminol, glutathione) in the BDL model. NAC was found to be effective on cholestasis-induced hepatotoxicity. However, NAC was inefficient as an antifibrotic agent within a 1-month period of administration in the BDL model.