Ameliorative potential of montelukast on ischemia-reperfusion injury induced vasculitic neuropathic pain in rat

Effect of Taxifolin on Ischemia/Reperfusion-Induced Oxidative Injury of Sciatic Nerve in Rats

BACKGROUND

Ischemia is a condition in which blood flow to tissues is decreased or entirely stopped for various reasons. The reperfusion process exacerbates damage caused by ischemia in the organs and tissues. Reactive oxygen species (ROS) are mainly responsible for ischemia-reperfusion (IR) damage. ROS increase results in lipid peroxidation (LPO) and oxidative stress. In the literature, taxifolin reportedly suppresses ROS production. This study aimed to determine the effect of taxifolin, which is a flavonoid, on IR injury of the sciatic nerve in rats.

METHODS

This study divided 30 albino Wistar rats into 3 groups: IR without medication (IR) group, taxifolin applied IR (TAX+IR) group, and only dissection made to the sciatic nerve sham group (SHAM). Sciatic nerve injury was induced by applying 2 hours of ischemia and 3 hours of reperfusion to the abdominal aorta and iliolumbar arteries. Biochemical and histopathologic investigations then were performed on sciatic nerve tissues. Malondialdehyde, total glutathione, glutathione reductase, and glutathione peroxidase were analyzed as oxidative stress markers, and tumor necrosis factor-α and interleukin-1β levels were evaluated as inflammatory stress markers in biochemical tests.

RESULTS

The IR group has statistically significantly high oxidant and cytokine levels and low antioxidant levels compared with the TAX+IR group. Taxifolin treatment was also shown to cause significant histopathologic improvement.

CONCLUSIONS

We suggest that taxifolin may be effective in preventing IR injury of the sciatic nerve.

The Effect of Lutein on Ischemia-reperfusion-induced Vasculitic Neuropathic Pain and Neuropathy in Rats

BACKGROUND/AIM

Neuropathic pain and neuropathy is commonly seen after ischemia-reperfusion injuries. Our aim was to evaluate the effect of lutein on ischemia-reperfusion (I/R)-induced vasculitic neuropathic pain and neuropathy in rats.

MATERIALS AND METHODS

An hour before anesthesia, 6 Albino Wistar male rats with I/R were orally administered with 1 mg/kg lutein (LIR group). Two groups of 6 such rats who underwent surgery were provided with 0.5 ml distilled water (as solvent) either via oral administration (SIR group) or by gavage (sham group or SG). One hour following the administration, the later femoral arteries of the LIR and SIR rats were closed using a sterile silk thread and ischemia was induced in the sciatic nerve for 4 h, followed by reperfusion for 24 h. The femoral artery of the SG group was not closed with suture. Next, 1 mg/kg lutein was re-administered only to the LIR group for 1 h, followed by measurement of the paw pain thresholds by the Basile Algesimeter. The levels of malondialdehyde (MDA), total glutathione (tGSH), nuclear factor-kB (NF-κB), and tumor necrosis factor-alpha (TNF-α) in the sciatic nerve tissues were measured, and the tissues were histopathologically examined.

RESULTS

We found that the MDA, NF-κB, and TNF-α levels were higher and the tGSH level was lower in the SIR group relative to those in the LIR group, and the differences were statistically significant. Significant histopathological damage was noted in the SIR group, whereas the LIR group demonstrated protection from oxidative damage.

CONCLUSION

Lutein is potentially useful in the treatment of I/R-related neuropathy and neuropathic pain.

Phase 2 trial of montelukast for prevention of pain in sickle cell disease

Cysteinyl leukotrienes (CysLTs) are lipid mediators of inflammation. In patients with sickle cell disease (SCD), levels of CysLTs are increased compared with controls and associated with a higher rate of hospitalization for pain. We tested the hypothesis that administration of the CysLT receptor antagonist montelukast would improve SCD-related comorbidities, including pain, in adolescents and adults with SCD. In a phase 2 randomized trial, we administered montelukast or placebo for 8 weeks. The primary outcome measure was a >30% reduction in soluble vascular cell adhesion molecule 1 (sVCAM), a marker of vascular injury. Secondary outcome measures were reduction in daily pain, improvement in pulmonary function, and improvement in microvascular blood flow, as measured by laser Doppler velocimetry. Forty-two participants with SCD were randomized to receive montelukast or placebo for 8 weeks. We found no difference between the montelukast and placebo groups with regard to the levels of sVCAM, reported pain, pulmonary function, or microvascular blood flow. Although montelukast is an effective treatment for asthma, we did not find benefit for SCD-related outcomes. This clinical trial was registered at www.clinicaltrials.gov as #NCT01960413.

Ameliorative effect of gallic acid in paclitaxel-induced neuropathic pain in mice

•

Gallic acid (GA) is a natural phenolic type of neuroprotective compound.

•

GA possesses anti-nociceptive action against paclitaxel-induced neurotoxicity.

•

GA inhibits THF-α mediated neuropathic pain sensation.

The present study has been investigated the role of gallic acid (GA) in paclitaxel-induced neuropathic pain. The neuropathic pain was developed with paclitaxel (PT: 2 mg/kg, i.p.) administration in mice. GA (20 and 40 mg/kg) and pregabalin (PreG: 5 mg/kg) were administered intravenously for 10 consecutive days. The neuralgic sensations were investigated by assessing various pain tests like acetone drop, pinprick, plantar, tail flick, and tail pinch test. Mice pain behaviors were evaluated on 0, 4^th, 8^th, 12^th and 16^th days. The levels of sciatic nerve thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide anion, calcium, myeloperoxidase (MPO), and TNF-α were estimated. Treatment of GA and PreG attenuate PT induced thermal &mechanical hyperalgesia and allodynia symptoms along with the reduction of TBARS, total calcium, TNF-α, superoxide anion, and MPO activity levels; and decreased GSH level. Therefore, it has been concluded that GA has potential neuroprotective actions against PT induced neuropathic pain due to it's anti-oxidant, anti-inflammation and regulation of intracellular calcium ion concentration.

Resveratrol alleviates nuclear factor-κB-mediated neuroinflammation in vasculitic peripheral neuropathy induced by ischaemia-reperfusion via suppressing endoplasmic reticulum stress

Vasculitic peripheral neuropathy (VPN) arises from an inflammatory obstruction in the blood vessels supplying peripheral nerves and subsequent ischaemic insults, which exhibits the clinical features of neuropathic pain and impaired peripheral nerve function. VPN induced by ischaemia-reperfusion (IR) has been reported to involve nuclear factor-κB (NF-κB)-mediated neuroinflammation. Recent studies have suggested that endoplasmic reticulum (ER) stress has been implicated in the development of peripheral neuropathies. Resveratrol possesses a potent anti-inflammatory capacity. We hypothesized that resveratrol may exert a protective effect against VPN through modulating the interrelated ER stress and NF-κB pathways. Male Sprague-Dawley rats were allocated into five groups: sham, sham + resveratrol 40 mg/kg (R40), IR, IR + R20 and IR + R40. VPN was induced by occluding the right femoral artery for 4 hours followed by reperfusion. Our data have shown that VPN induced by IR led to hind paw mechanical allodynia, heat hyperalgaesia, and impaired motor nerve conduction velocity (MNCV). With resveratrol intervention, the behavioural parameters were improved in a dose-dependent manner and the MNCV levels were increased as well. The molecular data revealed that VPN induced by IR significantly increased the expression of NF-κB as well as the ER stress sensor proteins, protein kinase RNA-like endoplasmic reticulum kinase, inositol-requiring enzyme 1 and activating transcription factor 6 in the sciatic nerves. More importantly, resveratrol significantly attenuated the expression of NF-κB and the ER stress sensor proteins after IR. In conclusion, resveratrol alleviates VPN induced by IR. The mechanisms may involve modulating NF-κB-mediated neuroinflammation via suppressing ER stress.

Vasculitic peripheral neuropathy induced by ischemia-reperfusion in the rat femoral artery involves activation of proinflammatory signaling pathway in the sciatic nerve

Ischemia-reperfusion (IR) in the rat femoral artery has been proposed as an experimental model of vasculitic peripheral neuropathy (VPN) which presents neuropathic pain and peripheral nerve injury patterns observed clinically. This study investigates the involvement of the proinflammatory signaling pathway underlying the peripheral mechanisms of VPN. Male Sprague-Dawley rats were allocated to receive either a sham operation or IR. IR was induced by occluding the right femoral artery for 4h followed by reperfusion periods from 0 to 72h. The behavioral parameters were assessed at baseline as well as at days 1, 2 and 3 after reperfusion. The time-course analyses of proinflammatory mediators in the sciatic nerves were also performed on rats of the sham group or IR groups with reperfusion periods of 0, 2, 4, 24 and 72h, respectively. The behavioral data confirmed that this VPN model induced hindpaw mechano-allodynia and heat hyperalgesia as well as impaired hindpaw grip strength. The molecular data revealed that IR in the femoral artery activated the expression of nuclear factor-κB (NF-κB) in the sciatic nerve indicating a neuroinflammatory response. Moreover, IR in the femoral artery increased the expression of proinflammatory cytokines TNF-α and IL-1β in the sciatic nerve. This study elucidated the novel time-course expression profiles of NF-κB and proinflammatory cytokines in VPN induced by IR which may be involved in the development of neuropathic pain. Since NF-κB is a key element during neuroinflammation, strategies targeting the NF-κB signaling pathway may provide therapeutic potential against VPN induced by IR.

The leukotriene receptor antagonist montelukast and its possible role in the cardiovascular field

BACKGROUND

Cysteinyl leukotrienes (LTC4, LTD4, and LTE4) are pro-inflammatory mediators of the 5-lipooxygenase (5-LO) pathway, that play an important role in bronchoconstriction, but can also enhance endothelial cell permeability and myocardial contractility, and are involved in many other inflammatory conditions. In the late 1990s, leukotriene receptor antagonists (LTRAs) were introduced in therapy for asthma and later on, approved for the relief of the symptoms of allergic rhinitis, chronic obstructive pulmonary disease, and urticaria. In addition, it has been shown that LTRAs may have a potential role in preventing atherosclerosis progression.

PURPOSE

The aims of this short review are to delineate the potential cardiovascular protective role of a LTRA, montelukast, beyond its traditional use, and to foster the design of appropriate clinical trials to test this hypothesis.

RESULTS AND CONCLUSIONS

What it is known about leukotriene receptor antagonists? •Leukotriene receptor antagonist, such as montelukast and zafirlukast, is used in asthma, COPD, and allergic rhinitis. • Montelukast is the most prescribed CysLT₁ antagonist used in asthmatic patients. • Different in vivo animal studies have shown that leukotriene receptor antagonists can prevent the atherosclerosis progression, and have a protective role after cerebral ischemia. What we still need to know? • Today, there is a need for conducting clinical trials to assess the role of montelukast in reducing cardiovascular risk and to further understand the mechanism of action behind this effect.

Ischemic-reperfusion of unilateral external iliac artery in rat: A new model for vasculitic femoral neuropathy

Clinically, ischemic environment during gynecological surgery at lithotomy position is most common causative factor for the development of vasculitic femoral neuropathy (VFN). The present study was designed to induce the clinically relevant rat model of VFN by ischemic-reperfusion (I/R) injury of unilateral external iliac artery (uEIA). The VFN was induced by 3, 4 and 5h occlusion of uEIA followed by reperfusion. The I/R of uEIA induced VFN was evaluated by (i) behavioral parameters i.e., hind limb temperature; weight bearing capacity; (ii) kinematic analysis i.e., paw posture, splay angle, static sciatic index (SSI), and ankle-angle tests; (iii) evaluation of pain perception i.e., plantar and pin prick; (iv) serum biochemical estimation i.e., nitrate, lipid peroxidation, TNF-α and calcium level; (v) evaluation of motor and sensory nerve conduction velocity; and (vi) measurement of nerve fiber density. The 4 and 5h occlusion of uEIA has produced the potential changes in behavioral, functional, electrophysiological, biochemical and histopathological assessment. The 5h occlusion of uEIA has shown to produce the mortality. Whereas, 3h occlusion does not produce the significant changes in the development of VFN. The 4h ischemic occlusion of uEIA has shown potential rat model of VFN due to its close mimicking capacity of VFN in human. Therefore, it can be useful to explore the newer anti-neuralgic medicine and with their pharmacodynamic action in the field of various neurovascular disorders.

Montelukast inhibits pentylenetetrazol-induced seizures in rats

Background

Montelukast is an antiinflammatory drug with an antioxidant property. In this study, we aimed to reveal whether montelukast has a preventive effect against seizures and post-seizure oxidative stress in pentylenetetrazol (PTZ)-induced seizures in rats.

Material/Methods

Of the 48 male Sprague-Dawley rats used in the study, 24 were assigned to EEG recordings (group A) and 24 were assigned to behavioral studies (group B). In group A, the electrodes were implanted on dura over the left frontal cortex for EEG recording. After 10 days, in group A, i.p. saline, 25, 50, or 100 mg/kg montelukast+35 mg/kg PTZ was administered to the rats. EEG was recorded and spike percentage was evaluated. In group B, i.p. saline, 25, 50, or 100 mg/kg montelukast+70 mg/kg PTZ was administered to the rats. Racine’s Convulsion Scale (RCS) and onset times of first myoclonic jerk (FMJ) was used to evaluate the seizures. Malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined in the brain tissue of animals.

Results

Animals treated with 50 or 100 mg/kg montelukast had significantly lower RCS and significantly increased FMJ onset time compared to the saline-treated animals. Moreover, groups given 25, 50, or 100 mg/kg montelukast had significantly lower MDA and higher SOD levels compared to the saline-treated group. The differences were more pronounced in the 100 mg/kg montelukast-pretreated group (p<0.001).

Conclusions

Montelukast showed anticonvulsant action and led to amelioration of oxidative stress markers in PTZ-induced seizures in rats.

Investigation of the role of non-selective calcium channel blocker (flunarizine) on cerebral ischemic-reperfusion associated cognitive dysfunction in aged mice

The present study was designed to investigate the role of flunarizine (a non-selective calcium channel blocker) on cerebral ischemic-reperfusion associated cognitive dysfunction in aged mice. Bilateral carotid artery occlusion of 12min followed by reperfusion for 24h was given to induce cerebral injury in male Swiss mice. The assessment of learning & memory was performed by Morris water maze test; motor in-coordination was evaluated by rota rod, lateral push and inclined beam walking tests; cerebral infarct size was quantified by triphenyltetrazolium chloride staining. In addition, reduced glutathione (GSH), total calcium and acetylcholinesterase (AChE) activity were also estimated in aged brain tissue. Donepezil treated group served as a positive control in this study. Ischemia reperfusion (I/R) injury produced significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Further, I/R injury also produced significant increase in levels of total calcium, AChE activity and decrease in GSH levels. Pretreatment of flunarizine significantly attenuated I/R induced infarct size, behavioral and biochemical changes. Hence, it may be concluded that, a non-selective calcium channel blocker can be useful in I/R associated cognitive dysfunction due to its anti-oxidant, anti-infarct and modulatory actions of neurotransmitters & calcium channels.

Montelukast attenuates neuropathic pain through inhibiting p38 mitogen-activated protein kinase and nuclear factor-kappa B in a rat model of chronic constriction injury

BACKGROUND

Cysteinyl leukotrienes and their receptors have been shown to be involved in the generation of neuropathic pain. We performed this study to determine the antagonistic effect of montelukast, a cysteinyl leukotrienes receptor antagonist, on neuropathic pain and its underlying mechanism.

METHODS

Neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve in rats. After CCI, rats were repeatedly administered montelukast (0.5, 1.0, and 2.0 mg/kg intraperitoneal, once daily) for a period of 14 days. Mechanical withdrawal threshold and thermal withdrawal latency were assessed before surgery and on days 1, 3, 5, 7, and 14 after CCI. The levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in the spinal cord were determined by enzyme-linked immunosorbent assay. The phosphorylation of p38 mitogen-activated protein kinase (MAPK) and activation of nuclear factor-kappaB (NF-κB) were assessed by Western blot. The expression of astrocyte marker glial fibrillary acidic protein and microglia marker Iba-1 and the coexpression of p-p38MAPK and Iba-1 or NF-κB and Iba-1 were observed by immunofluorescent staining.

RESULTS

The CCI group displayed significantly decreased mechanical withdrawal threshold and thermal withdrawal latency on days 1, 3, 5, 7 and 14 compared with sham groups (P <0.05, P < 0.0001), which were markedly increased by montelukast (P < 0.05, P < 0.01, P <0.0001). After administration with montelukast for 14 days, as biological markers of inflammation, the levels of IL-1β (P < 0.0001), IL-6 (P = 0.001 for low dosage, P < 0.0001 for middle and high dosages), and TNF-α (P =0.002, 0.001, < 0.0001 for low, middle, and high dosage, respectively) in the spinal cord were lower than those in the CCI group. Western blot analysis demonstrated that montelukast reduced the elevated expression of p-p38 MAPK (P =0.006, 0.015, < 0.0001 for low, middle, and high dosage, respectively) and NF-κB (P < 0.0001) in the spinal cord induced by CCI. Immunofluorescent staining showed that montelukast could inhibit CCI-induced activation of microglia but not astrocytes in the spinal cord. In addition, montelukast (2.0 mg/kg) significantly decreased the number of p38MAPK and Iba-1 or NF-κBp65 and Iba-1 double-positive cells.

CONCLUSIONS

These results suggest that montelukast could effectively attenuate neuropathic pain in CCI rats by inhibiting the activation of p38MAPK and NF-κB signaling pathways in spinal microglia.

Pharmacological evaluation of methanolic leaf extract of Swietenia mahagoni on acrylamide-induced neuropathic pain in rats

The present study was designed to investigate the antinociceptive effects of methanolic leaf extract of Swietenia mahagoni (MESM) on acrylamide-induced painful neuropathy in rats. The intraperitoneal administration of acrylamide (30 mg/kg; for 24 consecutive days) has been employed for the induction of painful neuropathy. Acrylamide induced nociceptive pain sensitive changes, which have been assessed by hot plate, Von Frey Hair, and tail immersion tests at different time intervals, that is, 0, 6, 12, 18, and 24th day. Furthermore, the biochemical changes, that is, thiobarbituric acid-reactive substances, reduced glutathione, and total calcium levels have been estimated in sciatic nerve tissue on 24th day and histopathological changes have been observed in sciatic nerve tissue sample. MESM and pregabalin have been administered for 14 consecutive days before 1 h of the each acrylamide injection. Administration of acrylamide resulted in significant changes in behavioral and biochemical parameters. Pretreatment of MESM ameliorated acrylamide-induced behavioral, biochemical, and histopathological changes in a dose-dependent manner, which is similar to that of pregabalin-pretreated group. These findings suggested that the neuroprotective effect of S. mahagoni may be due to its potential of antioxidative, calcium channel modulatory, and neuroprotective action.

Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia-reperfusion injury

The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.