Hypothalamic paraventricular nucleus stimulation reduces intestinal injury in rats with ulcerative colitis.

AIM: To investigate the effect and mechanism of stimulation of the hypothalamic paraventricular nucleus with glutamate acid in rats with ulcerative colitis (UC). METHODS: The rats were anesthetized with 10% chloral hydrate via abdominal injection and treated with an equal volume of TNBS + 50% ethanol enema, injected into the upper section of the anus with the tail facing up. Colonic damage scores were calculated after injecting a certain dose of glutamic acid into the paraventricular nucleus (PVN), and the effect of the nucleus tractus solitarius (NTS) and vagus nerve in alleviating UC injury through chemical stimulation of the PVN was observed in rats. Expression changes of C-myc, Apaf-1, caspase-3, interleukin (IL)-6, and IL-17 during the protection against UC injury through chemical stimulation of the PVN in rats were detected by Western blot. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in colon tissues of rats were measured by colorimetric methods. RESULTS: Chemical stimulation of the PVN significantly reduced UC in rats in a dose-dependent manner. The protective effects of the chemical stimulation of the PVN on rats with UC were eliminated after chemical damage to the PVN. After glutamate receptor antagonist kynurenic acid was injected into the PVN, the protective effects of the chemical stimulation of the PVN were eliminated in rats with UC. After AVP-Vl receptor antagonist ([Deamino-penl, val4, D-Arg8]-vasopressin) was injected into NTS or bilateral chemical damage to NTS, the protective effect of the chemical stimulation of PVN on UC was also eliminated. After chemical stimulation of the PVN, SOD activity increased, MDA content decreased, C-myc protein expression significantly increased, caspase-3 and Apaf-1 protein expression significantly decreased, and IL-6 and IL-17 expression decreased in colon tissues in rats with UC. CONCLUSION: Chemical stimulation of the hypothalamic PVN provides a protective effect against UC injury in rats. Hypothalamic PVN, NTS and vagus nerve play key roles in this process.

[Expression and clinical significance of cyclooxygenase-2 in medulloblastoma].

OBJECTIVE: To gain an insight into the possible relationship between the expression of cyclooxygenase-2 (COX-2) and the prognosis of the patients with medulloblastoma. METHODS: COX-2 expression was investigated in 52 medulloblastoma and 10 normal cerebellar tissue specimens by immunohistochemistry. Kaplan-Meier analyses, Log-rank test, and Cox proportional hazard model were used to explore the relationship between the percentage of COX-2 expression and the survival period of patients with medulloblastoma. RESULTS: Positive staining with COX-2 was either moderately or strongly observed in most of the medulloblastoma (51/52). Moreover, COX-2 was expressed not only in tumor cells, but also in the vascular endothelial cells of tumor. No COX-2 immunoreactivity was observed in normal cerebellar tissue. Kaplan-Meier analyses demonstrated that high COX-2 expression (> or = 50% of cells stained positive) correlated with poor survival for the study group as a whole (P < 0.0001). CONCLUSION: Our study provides evidence that COX-2 is expressed in the majority of medulloblastomas and that a potential role of COX-2 inhibitors as an adjuvant therapy for brain tumors may exist.