Effects of systemic administration of lidocaine and QX-314 on hyperexcitability of spinal dorsal horn neurons after incision in the rat

Inflammation and subsequent nociceptor sensitization in the bone marrow are involved in an animal model of osteoarthritis pain

AIMS

This study aimed to determine whether pathological changes in the bone marrow cause Osteoarthritis (OA) pain based on magnetic resonance imaging (MRI), immunohistochemistry, and electrophysiology.

MAIN METHODS

Adjuvant-induced arthritis (AIA) was achieved by injecting 150 μL of complete Freund's adjuvant into the right knee joints of male Sprague-Dawley rats. AIA rats were compared with saline-injected rats.

KEY FINDINGS

AIA significantly induced mechanical hyperalgesia and spontaneous pain in the right hind paw 1-14 days after induction. Intratibial injection of 50 μL of 1 % lidocaine significantly suppressed AIA-induced mechanical hyperalgesia (p = 0.0001) and spontaneous pain (p = 0.0006) 3 days after induction. In T2-weighted MRI, AIA induced high-signal intensity within the proximal tibial metaphysis, and the mean T2 values in this area significantly increased on days 3 (p = 0.0043) and 14 (p = 0.0012) after induction. AIA induced intraosseous edema and significantly increased the number of intraosseous granulocytes on days 3 (p < 0.0001) and 14 (p < 0.0001) after induction. The electrophysiological study on days 3-7 after induction showed significantly increased spontaneous firing rates (p = 0.0166) and evoked responses to cutaneous stimuli (brush, p < 0.0001; pinching, p = 0.0359) in the right hind paw plantar surface and intratibial stimuli (p = 0.0002) in wide-dynamic-range neurons of the spinal dorsal horn.

SIGNIFICANCE

Intraosseous changes caused by OA induce hypersensitivity in the sensory afferents innervating bone marrow may be involved in OA pain. Novel bone marrow-targeted therapies could be beneficial for treating OA pain.

Association between perioperative intravenous lidocaine and subjective quality of recovery: A meta-analysis of randomized controlled trials

STUDY OBJECTIVE

To evaluate the impact of perioperative intravenous lidocaine on the quality of recovery (QoR) following surgery.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

SETTING

Postoperative care.

INTERVENTION

Intravenous lidocaine during perioperative period.

PATIENTS

Adults undergoing surgery under general anesthesia.

MEASUREMENTS

The primary outcome was postoperative QoR measured with QoR-40 questionnaire, while the secondary outcomes included five individual dimensions (i.e., emotional, state, physical comfort, psychological support, physical independence, and pain) of QoR-40, intraoperative opioid consumption, and risk of chronic postsurgical pain (CPSP).

MAIN RESULTS

Medline, Cochrane Library, Google scholar, and EMBASE databases were searched from inception to June 2021. Fourteen RCTs involving 1148 patients in total undergoing elective surgery published from 2012 to 2021 were included. QoR-40 scores were evaluated at postoperative 24 h (12 trials), 72 h (one trial), and Day 5 (one trial), respectively. Pooled results revealed significantly higher global [mean difference (MD) = 9.65, 95% confidence interval (CI): 6.33 to 12.97; I² = 97%; 13 RCTs; n = 1085] and individual dimension QoR-40 scores in the lidocaine group than those in placebo group. Subgroup analysis demonstrated no significant impact of the type of surgery, age, gender, surgical time, anesthetic technique, lidocaine dosage, and time of assessment on global QoR-40 scores. The use of intravenous lidocaine was associated with a significant reduction in intraoperative remifentanil consumption compared with that in the placebo group (standardized MD = -0.91, 95%CI: -1.32 to -0.51; I² = 86%; 10 RCTs; n = 799). There was no difference in risk of CPSP between the two groups [relative risk (RR) = 0.65, 95%CI: 0.33 to 1.25; I² = 58%; 4 RCTs; n = 309].

CONCLUSION

Our results verified the efficacy of intravenous lidocaine for enhancing postoperative quality of recovery by using a validated subjective tool and reducing intraoperative remifentanil consumption in patients receiving elective surgery under general anesthesia. Further studies are warranted to verify its efficacy in the acute care setting.

Continuous Infusion of Ketamine and Lidocaine Either with or without Maropitant as an Adjuvant Agent for Analgesia in Female Dogs Undergoing Mastectomy

Maropitant, an antagonist of neurokinin-1 (NK-1) receptors, blocks the pharmacological action of substance P on the central and peripheral nervous systems. The objective of this study was to compare the antinociceptive and cardiorespiratory effects of the continuous intraoperative infusion of maropitant with ketamine and lidocaine in female dogs undergoing unilateral radical mastectomy. Twenty-four female dogs were used and were divided randomly into two groups (n = 12). The GLK group received ketamine bolus (1.0 mg/kg), lidocaine bolus (1.5 mg/kg), and continuous infusion of ketamine and lidocaine (10 mcg/kg/min and 50 mcg/kg/min), respectively; the GLKM group received the same anesthetic protocol combined with maropitant bolus (1.5 mg/kg/IV) and continuous infusion of maropitant (100 mcg/kg/h). Continuous infusion was initiated at the start of surgery and was maintained until 1 hour postoperatively. Pain was evaluated in the postoperative period using four scales and a digital analgesimeter. Data were analysed using analysis of variance, Student's t-test, Mann–Whitney test, and Friedman's test (P < 0.05). Kaplan–Meier curves were compared using the log-rank test. The results indicated lower pain scores, better survival curves with a lower number of patients requiring rescue analgesia, and lower peripheral sensitization, in the GLKM group than in the GLK group. It was concluded that the coadministration of maropitant with ketamine and lidocaine had an adjuvant effect with minimal cardiorespiratory effects and effective analgesia, improving pain management and patient comfort.

Efficacy of intravenous lidocaine in improving post-operative nausea, vomiting and early recovery after laparoscopic gynaecological surgery

Post-operative nausea and vomiting (PONV) is a major peri-operative complication. It has numerous adverse consequences that seriously affect the post-operative recovery of patients. The aim of the present study was to investigate the efficacy of intravenous lidocaine in improving PONV and recovery after laparoscopic gynaecological surgery. A total of 40 patients were randomly assigned to 2 groups: Group L (lidocaine group) and Group C (control group). The patients in Group L received intravenous lidocaine throughout the operation, while patients in Group C were given a saline infusion. Vital signs, recovery time, extubation time, dosage of remifentanil, first flatus time and defecation time of each patient were recorded. The incidence of PONV after surgery was also recorded. The recovery of the patients was evaluated by using the quality of recovery score (QoR-40). The total dose of remifentanil was significantly lower in Group L (P<0.05). However, the recovery time and extubation time were shorter in Group C (P<0.05). The first flatus time and defecation time were longer in Group C (P<0.05). The mean arterial pressure and heart rate in Group L were lower and more stable (P<0.05). At 6 h after surgery, the incidence of PONV was significantly lower in Group L vs. that in Group C (P<0.05). The QoR-40 score in Group C was significantly lower at 1 and 3 days after the operation compared with that in Group C (P<0.05). In conclusion, intravenous lidocaine administered to patients undergoing laparoscopic gynaecological surgery may reduce PONV and supports their early recovery [trial registration number in Chinese Clinical Trial Registry: ChiCTR-IOR-17010782 (March 5, 2017)].

Muscle pain induced by static contraction in rats is modulated by peripheral inflammatory mechanisms

Muscle pain is an important health issue and frequently related to static force exertion. The aim of this study is to evaluate whether peripheral inflammatory mechanisms are involved with static contraction-induced muscle pain in rats. To this end, we developed a model of muscle pain induced by static contraction performed by applying electrical pulses through electrodes inserted into muscle. We also evaluated the involvement of neutrophil migration, bradykinin, sympathetic amines and prostanoids. A single session of sustained static contraction of gastrocnemius muscle induced acute mechanical muscle hyperalgesia without affecting locomotor activity and with no evidence of structural damage in muscle tissue. Static contraction increased levels of creatine kinase but not lactate dehydrogenase, and induced neutrophil migration. Dexamethasone (glucocorticoid anti-inflammatory agent), DALBK (bradykinin B1 antagonist), Atenolol (β1 adrenoceptor antagonist), ICI 118,551 (β2 adrenoceptor antagonist), indomethacin (cyclooxygenase inhibitor), and fucoidan (non-specific selectin inhibitor) all reduced static contraction-induced muscle hyperalgesia; however, the bradykinin B2 antagonist, bradyzide, did not have an effect on static contraction-induced muscle hyperalgesia. Furthermore, an increased hyperalgesic response was observed when the selective bradykinin B1 agonist des-Arg⁹-bradykinin was injected into the previously stimulated muscle. Together, these findings demonstrate that static contraction induced mechanical muscle hyperalgesia in gastrocnemius muscle of rats is modulated through peripheral inflammatory mechanisms that are dependent on neutrophil migration, bradykinin, sympathetic amines and prostanoids. Considering the clinical relevance of muscle pain, we propose the present model of static contraction-induced mechanical muscle hyperalgesia as a useful tool for the study of mechanisms underlying static contraction-induced muscle pain.

Systemic QX-314 Reduces Bone Cancer Pain through Selective Inhibition of Transient Receptor Potential Vanilloid Subfamily 1-expressing Primary Afferents in Mice

BACKGROUND

The aim of this study was to determine whether systemic administration of QX-314 reduces bone cancer pain through selective inhibition of transient receptor potential vanilloid subfamily 1 (TRPV1)-expressing afferents.

METHODS

A mouse model of bone cancer pain was used. The authors examined the effects of bolus (0.01 to 3 mg/kg, n = 6 to 10) and continuous (5 mg kg h, n = 5) administration of QX-314 on both bone cancer pain-related behaviors and phosphorylated cyclic adenosine monophosphate response element-binding protein expression in dorsal root ganglion neurons (n = 3 or 6) and the effects of ablation of TRPV1-expressing afferents on bone cancer pain-related behaviors (n = 10).

RESULTS

The numbers of flinches indicative of ongoing pain in QX-314-treated mice were smaller than those in vehicle-treated mice at 10 min (3 mg/kg, 4 ± 3; 1 mg/kg, 5 ± 3 vs. 12 ± 3; P < 0.001; n = 8 to 9), 24 h (3 ± 2 vs. 13 ± 3, P < 0.001), and 48 h (4 ± 1 vs. 12 ± 2, P < 0.001; n = 5 in each group) after QX-314 administration, but impaired limb use, weight-bearing including that examined by the CatWalk system, and rotarod performance indicative of movement-evoked pain were comparable. QX-314 selectively inhibited the increase in phosphorylated cyclic adenosine monophosphate response element-binding protein expression in TRPV1-positive, but not in TRPV1-negative, dorsal root ganglion neurons compared to that in the case of vehicle administration (32.2 ± 3.0% vs. 52.6 ± 5.9%, P < 0.001; n = 6 in each group). Ablation of TRPV1-expressing afferents mimicked the effects of QX-314.

CONCLUSION

This study showed that systemic administration of QX-314 in mice inhibits some behavioral aspects of bone cancer pain through selective inhibition of TRPV1-expressing afferents without coadministration of TRPV1 agonists.

Effects of intravenous versus epidural lidocaine infusion on pain intensity and bowel function after major large bowel surgery: a double-blind randomized controlled trial

BACKGROUND

We compared the effects of intravenous lidocaine (IVL) with lumbar epidural lidocaine analgesia (LEA) on pain and ileus after open colonic surgery.

METHODS

Between December 2011 and February 2013, 60 patients were randomly allocated to IVL, LEA, or control group. The IVL group received intraoperatively lidocaine 2 % intravenously (1.5 mg/kg bolus, 2 mg/kg/h infusion) and normal saline (NS) epidurally. The LEA group received lidocaine epidurally (1.5 mg/kg bolus, 2 mg/kg/h infusion) and NS intravenously. The control group received NS both intravenously and epidurally, as bolus and infusion. All NS volumes were calculated as if containing lidocaine 2 % at the aforementioned doses. We assessed pain intensity at rest/cough at 1, 2, 4, 12, 24, and 48 h postoperatively (numerical rating scale 0-10), 48-h analgesic consumption, and time to first flatus passage.

RESULTS

Data from 60 patients (20 per group) were analyzed. The IVL group had significantly lower pain scores at rest and cough compared to LEA or control group only at 1, 2, and 4 h postoperatively (P < 0.005 for all comparisons). The 48-h analgesic requirements and time to first flatus passage did not differ significantly between IVL group and LEA or control group (P > 0.05).

CONCLUSIONS

Compared with LEA-lidocaine or placebo, intravenous lidocaine offered no clinically significant benefit in terms of analgesia and bowel function.

External QX-314 inhibits evoked cranial primary afferent synaptic transmission independent of TRPV1

The cell-impermeant lidocaine derivative QX-314 blocks sodium channels via intracellular mechanisms. In somatosensory nociceptive neurons, open transient receptor potential vanilloid type 1 (TRPV1) receptors provide a transmembrane passageway for QX-314 to produce long-lasting analgesia. Many cranial primary afferents express TRPV1 at synapses on neurons in the nucleus of the solitary tract and caudal trigeminal nucleus (Vc). Here, we investigated whether QX-314 interrupts neurotransmission from primary afferents in rat brain-stem slices. Shocks to the solitary tract (ST) activated highly synchronous evoked excitatory postsynaptic currents (ST-EPSCs). Application of 300 μM QX-314 increased the ST-EPSC latency from TRPV1+ ST afferents, but, surprisingly, it had similar actions at TRPV1- ST afferents. Continued exposure to QX-314 blocked evoked ST-EPSCs at both afferent types. Neither the time to onset of latency changes nor the time to ST-EPSC failure differed between responses for TRPV1+ and TRPV1- inputs. Likewise, the TRPV1 antagonist capsazepine failed to prevent the actions of QX-314. Whereas QX-314 blocked ST-evoked release, the frequency and amplitude of spontaneous EPSCs remained unaltered. In neurons exposed to QX-314, intracellular current injection evoked action potentials suggesting a presynaptic site of action. QX-314 acted similarly at Vc neurons to increase latency and block EPSCs evoked from trigeminal tract afferents. Our results demonstrate that QX-314 blocked nerve conduction in cranial primary afferents without interrupting the glutamate release mechanism or generation of postsynaptic action potentials. The TRPV1 independence suggests that QX-314 either acted extracellularly or more likely entered these axons through an undetermined pathway common to all cranial primary afferents.

The quaternary lidocaine derivative QX-314 produces long-lasting intravenous regional anesthesia in rats

Background

The lidocaine derivative, QX-314, produces long-lasting regional anesthesia in various animal models. We designed this study to examine whether QX-314 could produce long-lasting intravenous regional anesthesia (IVRA) in a rat model.

Methods

IVRA was performed on tail of rats. EC₅₀ (median effective concentration) of QX-314 in IVRA was determined by up-and-down method. IVRA on tail of rats was evaluated by tail-flick and tail-clamping tests. For comparison between QX-314 and lidocaine, 60 Sprague-Dawley rats were randomly divided into 6 groups (n = 10/group), respectively receiving 0.5 ml of 0.5% lidocaine, 0.25% QX-314, 0.5% QX-314, 1.0% QX-314, 2.0% QX-314 and normal saline. To explore the role of TRPV1 channel in IVRA of QX-314, 20 rats were randomly divided into 2 groups (n = 10/group), respectively receiving 0.5 ml of 1% QX-314 and 1% QX-314+75 µg/ml capsazepine. Toxicities of QX-314 on central nervous system and cardiac system were measured in rats according to Racine's convulsive scale and by electrocardiogram, respectively.

Results

QX-314 could produce long-lasting IVRA in a concentration-dependent manner. EC₅₀ of QX-314 in rat tail IVRA was 0.15±0.02%. At concentration of 0.5%, IVRA duration of QX-314 (2.5±0.7 hour) was significantly longer than that of 0.5% lidocaine (0.3±0.2 hour, P<0.001). TRPV1 channel antagonist (capsazepine) could significantly reduce the effect of QX-314. For evaluation of toxicities, QX-314 at doses of 5 or 10 mg/kg did not induce any serious complications. However, QX-314 at dose of 20 mg/kg (1% QX-314 0.5 ml for a rat weighing 250 g) induced death in 6/10 rats.

Conclusions

QX-314 could produce long-lasting IVRA in a concentration-dependent manner. This long-lasting IVRA was mediated by activation of TRPV1 channels. Evaluation of toxic complications of QX-314 confirmed that low but relevant doses of QX-314 did not result in any measurable toxicity.

Differential effects of peripheral versus central coadministration of QX-314 and capsaicin on neuropathic pain in rats

BACKGROUND

Neuropathic pain is common and difficult to treat. Recently a technique was developed to selectively inhibit nociceptive inputs by simultaneously applying two drugs: capsaicin, a transient receptor potential vanilloid receptor-1 channel activator, and QX-314, a lidocaine derivative that intracellularly blocks sodium channels. We used this technique to investigate whether transient receptor potential vanilloid receptor 1-expressing nociceptors contribute to neuropathic pain.

METHODS

The rat chronic constriction injury model was used to induce neuropathic pain in order to test the analgesic effects of both peripheral (perisciatic) and central (intrathecal) administration of the QX-314/capsaicin combination. The Hargreaves and von Frey tests were used to monitor evoked pain-like behaviors and visual observations were used to rank spontaneous pain-like behaviors.

RESULTS

Perisciatic injections of the QX-314/capsaicin combination transiently increased the withdrawal thresholds by approximately 3-fold, for mechanical and thermal stimuli in rats (n = 6/group) with nerve injuries suggesting that peripheral transient receptor potential vanilloid receptor 1-expressing nociceptors contribute to neuropathic pain. In contrast, intrathecal administration of the QX-314/capsaicin combination did not alleviate pain-like behaviors (n = 5/group). Surprisingly, intrathecal QX-314 alone (n = 9) or in combination with capsaicin (n = 8) evoked spontaneous pain-like behaviors.

CONCLUSIONS

Data from the perisciatic injections suggested that a component of neuropathic pain was mediated by peripheral nociceptive inputs. The role of central nociceptive terminals could not be determined because of the severe side effects of the intrathecal drug combination. We concluded that only peripheral blockade of transient receptor potential vanilloid receptor 1-expressing nociceptive afferents by the QX-314/capsaicin combination was effective at reducing neuropathic allodynia and hyperalgesia.

Systemic administration of lidocaine reduces morphine requirements and postoperative pain of patients undergoing thoracic surgery after propofol-remifentanil-based anaesthesia

BACKGROUND AND OBJECTIVE

Remifentanil is being increasingly used as an analgesic in fast-track surgery, but severe postoperative pain may happen occasionally. In this study, we evaluated the effects of systemic administration of lidocaine on postoperative pain and morphine requirements after propofol-remifentanil-based anaesthesia.

METHODS

Forty patients undergoing thoracic surgery were randomly assigned to lidocaine (33.0 microg kg(-1) min(-1)) and physiological saline control groups in propofol-remifentanil-based anaesthesia. The setting of the plasma concentration (C(p)) of the target-controlled infusion of propofol was adjusted according to the bispectral index of the electroencephalogram and blood pressure. The C(p) and effect-site concentration (C(e)) of propofol were calculated by target-controlled infusion pump during the intraoperative period. Pain scoring includes a four-point verbal rating scale, Riker's sedation-agitation scale and a visual analogue scale; the morphine requirement in the postanaesthesia care unit and the morphine consumption via a patient-controlled analgesia device on the ward were recorded during the postoperative period.

RESULTS

Morphine requirements within 30, 30-60 and 0-120 min in the postanaesthesia care unit of the lidocaine group decreased significantly (P < 0.05, n = 20 per group) compared with that of the control group. The four-point verbal rating scale at 30 min in the postanaesthesia care unit, visual analogue scale at 6 h on coughing and patient-controlled analgesia morphine consumption during 2-6 h postoperative time were also significantly (P < 0.05, n = 20 per group) reduced in the lidocaine group. In addition, the intraoperative propofol C(e) in the lidocaine group during the periods of intubation, organ resection, closing of chest cavity and extubation was significantly lower (P < 0.05, n = 20 per group) than that in the control group under the same hypnotic depth.

CONCLUSION

Systemic administration of lidocaine could reduce morphine requirements, postoperative pain and intraoperative propofol C(e) of patients undergoing thoracic surgery after propofol-remifentanil-based anaesthesia.

Meta-analysis of intravenous lidocaine and postoperative recovery after abdominal surgery

Background

Continuous intravenous administration of lidocaine may decrease the duration of ileus and pain after abdominal surgery.

Methods

Three databases (Medline, Embase and the Cochrane Controlled Trials Register) were searched to retrieve randomized controlled trials comparing continuous intravenous lidocaine infusion during and after abdominal surgery with placebo. Study design was scored using the Oxford Quality Score based on randomization, double-blinding and follow-up. Outcome measures were duration of ileus, length of hospital stay, postoperative pain, and incidence of nausea and vomiting.

Results

Eight trials were selected. A total of 161 patients received intravenous lidocaine, with 159 controls. Intravenous lidocaine administration decreased the duration of ileus (weighted mean difference (WMD) − 8·36 h; P &lt; 0·001), length of hospital stay (WMD − 0·84 days; P = 0·002), postoperative pain intensity at 24 h after operation on a 0–100-mm visual analogue scale (WMD − 5·93 mm; P = 0·002), and the incidence of nausea and vomiting (odds ratio 0·39; P = 0·006).

Conclusion

Continuous intravenous administration of lidocaine during and after abdominal surgery improves patient rehabilitation and shortens hospital stay.

Ongoing activity in trigeminal wide-dynamic range neurons is driven from the periphery

Ongoing activity of spinal trigeminal neurons is observed under various conditions and suggested to be responsible for ongoing headache. It can be spontaneous, i.e. arising intrinsically from the neuron, or the product of descending influences from other central neurons, or maintained by ongoing afferent input. The aim of the present study was to examine if ongoing activity of neurons in different subnuclei of the spinal trigeminal nucleus is driven from peripheral afferent input. Experiments were performed in Wistar rats anesthetized with isoflurane or Nembutal/urethane. Ongoing activity of single wide-dynamic range (WDR) neurons was recorded with carbon fiber glass microelectrodes in two subnuclei of the spinal trigeminal nucleus: oral (Sp5O) and caudal (Sp5C). Peripheral receptive fields were evaluated using von Frey filaments. Sp5O neurons received peripheral input from facial areas innervated by the mandibular branch of the trigeminal nerve. Units in Sp5C had receptive fields in the surgically exposed dura mater and in facial areas innervated by the ophthalmic and maxillary branch of the trigeminal nerve. Saline or the local anesthetic lidocaine was locally applied onto the exposed dura mater or microinjected into V3 (for Sp5O units) or V1/V2 (for Sp5C units) divisions of the trigeminal ganglion via the infraorbital channel. Local application of lidocaine onto the exposed dura caused mechanical insensitivity of dural receptive fields but not significant decrease in ongoing activity. Microinjection of lidocaine but not saline into the trigeminal ganglion was followed by a substantial decrease in both the receptive field size and the activity of the recorded WDR units. Mechanical insensitivity of receptive fields after trigeminal ganglion blockade was accompanied by the disappearance of ongoing activity. We conclude that the ongoing activity of WDR neurons in the spinal trigeminal nucleus, which may be indicative for processes of sensitization, is driven remotely by ongoing afferent input.