Haihua Shu

Resolvin D1 protects against hepatic ischemia/reperfusion injury in rats.

OBJECTIVE Inflammatory responses play an important role in the tissue damage during hepatic ischemia/reperfusion (I/R). Some resolvins have been shown to have protective properties in reducing I/R injury in the heart and kidney. The aim of the study was to investigate the effects of resolvin D1 (RvD1) on hepatic I/R. METHODS Partial warm ischemia was produced in the left and middle hepatic lobes of Sprague-Dawley rats for 60 min, followed by 6h of reperfusion. Rats received either RvD1 (5 μg/kg) or vehicle by intravenous injection prior to ischemia. On the basis of treatment with RvD1, some rats further received the PI3K inhibitor LY294002. Blood and tissue samples from the groups were collected after 6-h reperfusion. RESULTS Our results indicate that the RvD1 receptor ALX/FPR2 is present in liver, and that pretreatment with RvD1 prior to I/R insult significantly blunted I/R-induced elevations of alanine aminotransferase (AST) and aspartate aminotransferase (ALT), and significantly improved the histological status of the liver. Moreover, RvD1 significantly inhibited inflammatory cascades, as demonstrated by attenuations of IL-6, TNF-α and myeloperoxidase levels. Reduced apoptosis, and increased phosphorylation of Akt, were observed in the RvD1 group compared with the control I/R group. These effects of RvD1 on hepatic I/R injury were diminished by the PI3K inhibitor. CONCLUSIONS Administration of RvD1 prior to hepatic I/R attenuates hepatic injury, at least in part through inhibition of inflammatory response and enhancement of phosphorylation of Akt.

Pentazocine-induced antinociception is mediated mainly by μ-opioid receptors and compromised by κ-opioid receptors in mice.

Pentazocine is a widely used mixed agonist-antagonist opioid. Previous animal studies have demonstrated that pentazocine-induced antinociception displayed a ceiling effect characterized by biphasic dose response with a increasing and then descending analgesia like a bell-shaped curve. This study attempted to clarify the mechanisms underlying such dose-response relationships. ddY and C57BL/6J mice received subcutaneous injection of saline or pentazocine (3, 10, 30, 56, or 100 mg · kg−1), at 120 min after subcutaneous injection of saline, a μ-opioid receptor antagonist clocinnamox mesylate (C-CAM) (5 mg · kg−1), a κ-opioid receptor antagonist nor-binaltorphimine (nor-BNI) (10 mg · kg−1), or the combination of C-CAM and nor-BNI. The antinociceptive effects of pentazocine were evaluated using tail pressure, hot plate, tail flick, and acetic acid writhing tests. Without pretreatment with an opioid receptor antagonist, the antinociceptive effects of pentazocine exhibited biphasic bell-shaped dose-response curves peaking at 30 mg · kg−1. C-CAM completely and partly antagonized the antinociception induced by pentazocine at low (3–30 mg · kg−1) and high (56–100 mg · kg−1) doses, respectively. nor-BNI enhanced the antinociception by pentazocine at high doses and turned the later descending portion of the biphasic dose-response curves into a sigmoid curve. The combination of C-CAM and nor-BNI completely abolished the antinociception by pentazocine at all doses. Our results suggest pentazocine produces antinociception primarily via activation of μ-opioid receptors, but at high doses, this μ-opioid receptor-mediated antinociception is antagonized by concomitant activation of κ-opioid receptors. This provides the first reasonable hypothesis to explain the ceiling effects of pentazocine analgesia characterized by a biphasic dose response.

The comparison of effects of processed Aconiti tuber, U50488H and MK-801 on the antinociceptive tolerance to morphine.

In the previous studies, we demonstrated that an oriental herbal medicine, processed Aconiti tuber (PAT), at subanalgesic doses could inhibit or reverse the antinociceptive tolerance to morphine. In the present study, we compared the effect of PAT, trans-(+/-)-3,4-dichloro-N-methyl-N-(2-(1-pyrrolidin)cyclohexyl)-benzeneacetamide methane sulfonate hydrate (U50488H), a selective kappa opioid receptor (KOR) agonist, and (-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine-maleate (MK-801), a N-methyl-D-aspartate (NMDA) receptor antagonist, on the antinociceptive tolerance to morphine in the same experimental condition. Mice received subcutaneous morphine (10 mg/kg), and oral PAT at a subanalgesic dose (0.3 g/kg for mechanical or 1.0 g/kg for thermal test), or intraperitoneal U50488H at a subanalgesic dose (3 mg/kg), or MK-801 at a subanalgesic dose (0.1 mg/kg) once daily for 14 days. The mechanical nociceptive threshold was measured before, and at 60 min by tail pressure testing, and thermal nociceptive latency was measured before, and at 30 min by hot plate testing, after daily morphine injections. PAT and U50488H could not only inhibit the development of morphine tolerance but also reverse the already-developed morphine tolerance, while MK-801 could only inhibit the development of morphine tolerance but not reverse the already-developed morphine tolerance, in both mechanical and thermal nociceptive tests. These data suggested that PAT, an indirect-acting KOR agonist, share the common pharmacological property of KOR agonists on morphine tolerance, and that PAT may be superior to some NMDA receptor antagonists which do not reverse already-developed morphine tolerance.

Does Intraoperative Ulinastatin Improve Postoperative Clinical Outcomes in Patients Undergoing Cardiac Surgery: A Meta-Analysis of Randomized Controlled Trials

Introduction. The systematic meta-analysis of randomized controlled trials (RCTs) evaluated the effects of intraoperative ulinastatin on early-postoperative recovery in patients undergoing cardiac surgery. Methods. RCTs comparing intraoperative ulinastatin with placebo in cardiac surgery were searched through PubMed, Cochrane databases, Medline, SinoMed, and the China National Knowledge Infrastructure (1966 to May 20th, 2013). The primary endpoints included hospital mortality, postoperative complication rate, length of stay in intensive care unit, and extubation time. The physiological and biochemical parameters illustrating postoperative cardiac and pulmonary function as well as inflammation response were considered as secondary endpoints. Results. Fifteen RCTs (509 patients) met the inclusion criteria. Ulinastatin did not affect hospital mortality, postoperative complication rate, or ICU length of stay but reduced extubation time. Ulinastatin also increased the oxygenation index on postoperative day 1 and reduced the plasma level of cardiac troponin-I. Additionally, ulinastatin inhibited the increased level of tumor necrosis factor-alpha, polymorphonuclear neutrophil elastase, interleukin-6, and interleukin-8 associated with cardiac surgery. Conclusion. Ulinastatin may be of value for the inhibition of postoperative increased inflammatory agents and most likely provided pulmonary protective effects in cardiac surgery. However, larger adequately powered RCTs are required to define the clinical effect of ulinastatin on postoperative outcomes in cardiac surgery.

Anti-hypersensitivity effects of Shu-jing-huo-xue-tang, a Chinese herbal medicine, in CCI-neuropathic rats

AIM OF THE STUDY Shu-jing-huo-xue-tang (SJHXT) (Japanese name: Sokei-kakketu-to), a traditional Chinese herbal medicine composed of 17 crude drugs, has been prescribed over hundreds of years for treatment of chronic pain syndromes. We evaluated if oral SJHXT could suppress neuropathic pain behaviors in rats with chronic constriction injury (CCI) of the sciatic nerve. MATERIALS AND METHODS (1) Rats received repeated oral SJHXT 0.5 or 1.0 g/kg once daily for 14 days starting 24 h after CCI surgery, while neuropathic manifestations were evaluated until day 20 post-CCI. (2) Other groups of rats received single oral SJHXT 1.0 g/kg on day 14 post-CCI. (3) Additional groups of rats received oral SJHXT 1.0 g/kg on day 14 post-CCI, concomitantly with intraperitoneal yohimbine 1 mg/kg or methysergide 5 mg/kg. Neuropathic manifestations, including mechanical allodynia and thermal hyperalgesia, were evaluated with paw withdrawal responses to increasing mechanical pressure and radiant heat, respectively. RESULTS Mechanical allodynia and thermal hyperalgesia developed by day 14 post-CCI. Repeated oral SJHXT for 14 days produced anti-allodynic and anti-hyperalgesic effects that outlasted the period of drug administration. Single oral SJHXT on day 14 also produced significant anti-allodynic and anti-hyperalgesic effects, which were inhibited by yohimbine, an alpha-2 adrenoceptor antagonist, but not by methysergide, a serotonin receptor antagonist. CONCLUSIONS Oral SJHXT produced anti-hypersensitivity effects by actions on alpha-2 adrenoreceptors in CCI-neuropathic rats, and chronic oral administration of SJHXT could produce the long-lasting anti-hypersensitivity effects.

Inhibitory effect of low-dose pentazocine on the development of antinociceptive tolerance to morphine

PurposeThe development of antinociceptive tolerance to morphine is one of the major problems in its clinical use. Therefore, exploring effective measures to prevent morphine tolerance is of great clinical relevance. We evaluated whether pentazocine could prevent morphine tolerance in mice.MethodsFive groups of male ICR mice received repeated subcutaneous (s.c.) injections of morphine at a high dose (10 mg·kg−1) or saline, concomitantly with s.c. injections of pentazocine at low, subanalgesic doses (0.1, 0.3, or 1.0 mg·kg−1) or saline, respectively, once daily for 14 days. On day 15, mice received co-injections of morphine and pentazocine 120 min after pretreatment with nor-binaltorphimine (5 mg·kg−1), a selective κ-opioid receptor antagonist. The tail pressure threshold was measured before and 60 min after the daily drug co-injections.ResultsRepeated s.c. co-injections of morphine and saline resulted in a progressive decrease in morphine-induced antinociception, due to the development of morphine tolerance. Co-injections of pentazocine (0.1, 0.3, and 1.0 mg·kg−1) with morphine potentiated the morphine-induced antinociception dose-dependently by preventing the development of morphine tolerance. Nor-binaltorphimine completely inhibited the chronic antinociception maintained by co-injections of morphine and pentazocine.ConclusionWhen chronically co-administered with morphine, pentazocine at low, subanalgesic doses dose-dependently potentiated morphine-induced antinociception in morphine-tolerant mice, through its κ-opioid-receptor-mediated tolerance-preventing activity. Because pentazocine is the only agonist-antagonist analgesic that has an effective oral formulation suitable for chronic administration, the results of the present study warrant clinical trials of pentazocine to assess its tolerance-preventing activity in patients with cancer pain.

High doses of processed Aconiti tuber inhibit the acute but potentiate the chronic antinociception of morphine.

AIM OF THE STUDY In this study, we investigated the effects of processed Aconiti tuber (PAT), an oriental herbal medicine, at analgesic doses on acute morphine antinociception in morphine-naïve mice and morphine tolerance in morphine-tolerant mice. MATERIALS AND METHODS In acute experiments, mice received subcutaneous (s.c.) morphine (2, 5, or 10 mg/kg) and oral distilled water or PAT (0.3, 1.0, or 3.0 g/kg). The mechanical nociceptive threshold (MNT) and thermal nociceptive latency (TNL) were measured with the tail pressure test and tail flick test, respectively, before, and at 30, 60, 90, and 120 min after s.c. morphine injection. In chronic experiments, mice received s.c. morphine (10 mg/kg) and oral distilled water or PAT (0.3, 1.0, or 3.0 g/kg) once daily for 11 days. MNT was measured before, and at 60 min after, and TNL was measured before, and at 30 min after, daily morphine injections on days 1-11. RESULTS PAT at analgesic doses inhibited the acute antinociceptive effect of morphine dose-dependently in morphine-naïve mice. In contrast, PAT at analgesic doses potentiated the chronic antinociceptive effect of morphine dose-dependently by inhibiting the development of morphine tolerance dose-dependently. These effects of PAT on acute and chronic morphine antinociception were mediated through activation of kappa-opioid receptors. CONCLUSIONS These results indicated that chronic co-administration of PAT at analgesic doses with morphine could provide better-maintained morphine analgesia in a long-term morphine treatment after initial inhibition of acute morphine antinociception for a brief period of time.

High-dose pentazocine antagonizes the antinociception induced by high-dose morphine

AIMS To investigate the effects of high doses of pentazocine on antinociception induced by a high dose of morphine and the role of the kappa-opioid receptors (KORs) in these effects in mice. MAIN METHODS Sixty-six C57BL/6J mice were pretreated with a KOR antagonist, nor-binaltorphimine (nor-BNI) (10mg·kg(-1)), or a normal saline placebo. All the mice received a subcutaneous injection of morphine (10mg·kg(-1)) 120min later and different doses of pentazocine (3, 10, 30, 56, 100mg·kg(-1)) or a normal saline placebo. A tail pressure test, hot plate test and tail flick test were performed before and at 30, 60, 90 and 120min after the injection of morphine. KEY FINDINGS The tail pressure test, hot plate test and tail flick test showed that pentazocine at doses of 10 to 100mg·kg(-1), but not at 3mg·kg(-1), had significant antagonizing effects on the antinociception induced by high-dose morphine to mechanical and thermal pain, and nor-BNI did not affect antinociception in combination with pentazocine at 10 to 100mg·kg(-1) and morphine at 10mg·kg(-1). SIGNIFICANCE High-doses of pentazocine antagonize the antinociception induced by a high-dose of morphine in a dose-dependent manner, and this antagonistic effect is not associated with the activation of KORs.

Effects of three forms of local anesthesia on perioperative fentanyl-induced hyperalgesia

Both local infiltration analgesia (LIA) and nerve block are common analgesic modalities for pain relief after surgery. The aim of the current study was to investigate the effects of those two modalities on pain behavior and the expression of pro-inflammatory cytokines such as interleukin (IL)-1β and IL-6 and tumor necrosis factor-α (TNF-α) in the spinal cord and dorsal root ganglion (DRG) in a rat model of perioperative fentanyl induced hyperalgesia. Rats were injected with fentanyl (60 μg/kg) 4 times and received a plantar incision after the second injection or they received pre-incision LIA and sciatic nerve block (SNB) or post-incision LIA with levobupivacaine (0.5%, 0.2 mL). Mechanical and thermal nociceptive thresholds were assessed using the tail pressure test and paw withdrawal test on the day before drug injection, 1 and 4 hours after injection, and 1-7 days later. The lumbar spinal cord and dorsal root ganglia were collected from rats in each group to measure IL-1β, IL-6, and TNF-α on the day before drug injection, 4 hours after injection, and 1, 3, 5, and 7 days later. Fentanyl and an incision induced a significantly delayed mechanical hyperalgesia in the tail and thermal hyperalgesia in both hind paws and up-regulation of pro-inflammatory cytokines in the spinal cord and dorsal root ganglia. Rats treated with pre-incision LIA and SNB or post-incision LIA had alleviated hyperalgesia and significantly reduced levels of IL-1β, IL-6, and TNF-α compared to the control group. LIA and SNB partly prevented perioperative fentanyl-induced hyperalgesia and up-regulation of pro-inflammatory cytokines in the spinal cord and dorsal root ganglia.

Effect of Parecoxib as an Adjunct to Patient-Controlled Epidural Analgesia after Abdominal Hysterectomy: A Multicenter, Randomized, Placebo-Controlled Trial

Objective This multicenter, randomized, placebo-controlled study evaluated the efficacy and side effects of parecoxib during patient-controlled epidural analgesia (PCEA) after abdominal hysterectomy. Methods A total of 240 patients who were scheduled for elective abdominal hysterectomy under combined spinal-epidural anesthesia received PCEA plus postoperative intravenous parecoxib 40 mg or saline every 12 h for 48 h after an initial preoperative dose of parecoxib 40 mg or saline. An epidural loading dose of a mixture of 6 mL of 0.25% ropivacaine and 2 mg morphine was administered 30 min before the end of surgery, and PCEA was initiated using 1.25 mg/mL ropivacaine and 0.05 mg/mL morphine with a 2-mL/h background infusion and 2-mL bolus with a 15-min lockout. The primary end point of this study was the quantification of the PCEA-sparing effect of parecoxib. Results Demographic data were similar between the two groups. Patients in the parecoxib group received significantly fewer self-administrated boluses (0 (0, 3) vs. 7 (2, 15), P < 0.001) and less epidural morphine (5.01 ± 0.44 vs. 5.95 ± 1.29 mg, P < 0.001) but experienced greater pain relief compared with the control group (P < 0.001). Patient global satisfaction was higher in the parecoxib group than the control group (P < 0.001). Length of hospitalization (9.50 ± 2.1, 95% CI 9.12~9.88 vs. 10.41 ± 2.6, 95% CI 9.95~10.87, P = 0.003) and postoperative vomiting (17% vs. 29%, P < 0.05) were also reduced in the parecoxib group. There were no serious adverse effects in either group. Conclusion Our data suggest that adjunctive parecoxib during PCEA following abdominal hysterectomy is safe and efficacious in reducing pain, requirements of epidural analgesics, and side effects. Trial Registration ClinicalTrials.gov (NCT01566669)