Upregulation of spinal cyclooxygenase-2 in rats after surgical incision.

BACKGROUND: Although upregulation of cyclooxygenase (COX)-2 in spinal cord after peripheral inflammation has been well documented, the effect of surgery on spinal COX-2 has not been examined in detail. The present study uses a bilateral foot incision in rats to examine the magnitude and duration of surgically induced changes in spinal COX-2 protein. METHODS: A longitudinal incision was made in both plantar hind paws of isoflurane-anesthetized rats. Spinal cords were removed at various postoperative times (1-48 h), and spinal COX-2 protein levels were compared with the results of Western blot analysis. Ropivacaine-induced blockade of sciatic nerve function was used to determine the importance of afferent nerve activity on spinal COX-2 after incision. Dexamethasone and the COX-2-selective inhibitor L-745,337 were administered intrathecally to modulate spinal COX-2 after incision. RESULTS: COX-2 protein levels increased in the lumbar spinal cord at 3 (1.32-fold) and 6 (1.26-fold) h after bilateral foot incision. At later times, lumbar COX-2 levels were no different than in control animals not undergoing surgery. Cervical COX-2 protein levels remained unchanged. Sciatic nerve blockade with ropivacaine did not prevent the increase in lumbar spinal COX-2 protein levels after incision. Intrathecal dexamethasone decreased lumbar spinal COX-2 levels after incision, and an intrathecal COX-2-selective inhibitor did not reduce the COX-2 upregulation. CONCLUSIONS: After bilateral foot incision in rats, lumbar spinal COX-2 protein levels increase, although the magnitude and duration are less than reported in models of peripheral inflammation. This COX-2 upregulation does not seem to be mediated by afferent nerve activity.

[Determination of ultra-trace rare-earth elements in human plasma by inductively coupled plasma mass spectrometry].

Inductively coupled plasma mass spectrometry (ICP-MS), highly sensitive inorgnic analytic technique, fits to determine ultra-trace rare-earth elements in human plasma. Under the optimized conditions detection limits for 15 rare-earth elements are in the range of 0.7 (for Eu)-5.4 (for Gd) ng.L-1. Indium as an internal standard element is used to compensate for matrix suppression effect and sensitivity drift. Three kinds of preparation methods, diluted with 1% HNO3, digested with HNO3-H2O2 and with HNO3-HClO4, are checked and compared, and the former is the simplest way to be measured. The samples diluted with 1% HNO3, stored in 4 degrees C, are very steady for 16 days. With the method, 11 healthy plasma samples in Changchun area of China are analysed.

[Effects of platelet activating factor and platelet activating factor receptor antagonist on spinal cord blood flow after spinal cord injury].

Platelet activating factor (PAF) and PAF receptor antagonist BN52021 were respectively administered by intrathecal or intravenous injection in cats. We observed their effects on blood flow and TXB2/ 6-keto-PGF1 alpha ratio (T/K ratio) in injured spinal cord and its adjacent region (L2-L4)s after trauma. The results showed that gray matter and white matter blood flow at L2-L4 segment significantly decreased T/K ratio elevated evidently in PAF group as compared with simple spinal cord injury, while gray matter and white matter blood flow at L2-L4 segment significantly increased and T/K ratio markedly decreased in BN52021 group as compared with simple spinal cord injury group. The results demonstrate and that PAF is an important factor leading to spinal cord blood flow reduction after trauma, and that PAF receptor antagonist BN52021 can evidently improve spinal cord blood flow and relieve secondary damage after trauma.