Effects of N-acetylcysteine on spinal cord oxidative stress biomarkers in rats with neuropathic pain

Nandrolone decanoate induces heart injury via oxidative damage and mitochondrial apoptotic pathway by regulation of TLR4/NF-κB/NLRP3 axis in male rats: The rescue effect of N-acetylcysteine

Myocardial apoptosis is a leading cause of damage in cardiac tissues of nandrolone (ND) treatment. However, its molecular mechanism is not fully understood. This study aims to investigate the effect of ND with or without N -acetylcysteine (NAC) treatment on oxidative damage and TLR4/NF-κB /NLRP3 signaling pathway in the heart of male rats. Eighteen male Wistar rats with a weight range of 220 ± 10 g were selected. They were divided into three groups (n = 6): control (C) group, ND group, NAC + ND group. After six weeks of treatment, the TUNEL staining indicated that ND increased the number of apoptotic cells in the hearts of male rats. The molecular analysis demonstrated that ND exposure resulted in increased protein levels of cytochrome c, c-Caspase-3/p-Caspase-3 ratio, p53, TLR4, NF-κB, NLRP3, and 8-OHdG with a concomitant up-regulation of LDH and CK-MB enzymes activity in the heart tissue compared to the C group. Our findings suggested that ND can cause damage to heart tissue via induction of DNA damage, apoptosis, and probably TLR4/NF-κB/NLRP3 signaling pathway plays a crucial role in this process. It also demonstrates that these negative effects of ND can be reduced by using NAC treatment as an antioxidant and anti-inflammatory agent.

Therapeutic Efficacy of Intranasal N-Acetyl-L-Cysteine with Cell-Penetrating Peptide-Modified Polymer Micelles on Neuropathic Pain in Partial Sciatic Nerve Ligation Mice

Background/Objectives: We previously demonstrated that the intranasal administration of cell-penetrating Tat peptide-modified carrier, PEG-PCL-Tat, improves drug delivery to the central nervous system. This study aimed to evaluate the potential of the post-onset intranasal administration of N-acetyl-L-cysteine (NAC) combined with PEG-PCL-Tat (NAC/PPT) for neuropathic pain. Methods: Neuropathic pain was induced by partial sciatic nerve ligation (PSNL) in mice. Mechanical allodynia was assessed using the von Frey test on days 11-14 post-ligation. NAC or NAC/PPT was intranasally administered after pain onset. Western blotting and immunohistochemistry were conducted to evaluate ionized calcium-binding adapter molecule 1 (Iba-1) expression and microglial activation in the spinal cord. Results: Mechanical allodynia was exacerbated 11 days after the ligation in PSNL mice. The intranasal administration of NAC alone prevented allodynia exacerbation but failed to provide a therapeutic effect against allodynia in PSNL mice. In contrast, NAC/PPT administration ameliorated PSNL-induced tactile allodynia, with maximum efficacy seen 13 and 14 days after ligation. Western blotting demonstrated that Iba-1 levels tended to increase in PSNL mice compared to controls. This trend of increased Iba-1 levels in PSNL mice was attenuated by the administration of NAC/PPT, but not by NAC alone. Immunohistochemistry revealed an increased number of Iba-1-stained microglia in the ipsilateral spinal cord of PSNL mice, which were significantly suppressed by the administration of NAC/PPT. Conclusions: These results suggest that the post-onset intranasal administration of NAC/PPT ameliorates mechanical allodynia by suppressing microglia induction and that intranasal delivery with PEG-PCL-Tat might be a useful tool for the pharmacological management of neuropathic pain.

The Mechanism and Inflammatory Markers Involved in the Potential Use of N-acetylcysteine in Chronic Pain Management

N-acetylcysteine (NAC) has established use as an antidote for acetaminophen overdose and treatment for pulmonary conditions and nephropathy. It plays a role in regulating oxidative stress and interacting with various cytokines including IL-1β, TNFα, IL-8, IL-6, IL-10, and NF-κB p65. The overexpression of reactive oxygen species (ROS) is believed to contribute to chronic pain states by inducing inflammation and accelerating disease progression, favoring pain persistence in neuropathic and musculoskeletal pain conditions. Through a comprehensive review, we aim to explore the mechanisms and inflammatory pathways through which NAC may manage neuropathic and musculoskeletal pain. Evidence suggests NAC can attenuate neuropathic and musculoskeletal pain through mechanisms such as inhibiting matrix metalloproteinases (MMPs), reducing reactive oxygen species (ROS), and enhancing glutamate transport. Additionally, NAC may synergize with opioids and other pain medications, potentially reducing opioid consumption and enhancing overall pain management. Further research is needed to fully elucidate its therapeutic potential and optimize its use in pain management. As an adjuvant therapy, NAC shows potential for chronic pain management, offering significant benefits for public health.

Novel Drug Targets and Emerging Pharmacotherapies in Neuropathic Pain

Neuropathic pain is a debilitating condition characterized by abnormal signaling within the nervous system, resulting in persistent and often intense sensations of pain. It can arise from various causes, including traumatic nerve injury, neuropathy, and certain diseases. We present an overview of current and emerging pharmacotherapies for neuropathic pain, focusing on novel drug targets and potential therapeutic agents. Current pharmacotherapies, including tricyclic antidepressants, gabapentinoids, and serotonin norepinephrine re-uptake inhibitors, are discussed, as are emerging treatments, such as ambroxol, cannabidiol, and N-acetyl-L-cysteine. Additionally, the article highlights the need for further research in this field to identify new targets and develop more effective and targeted therapies for neuropathic pain management.

Men suffering from category III chronic prostatitis may benefit from N-acetylcysteine as an adjunct to alpha-blockers

OBJECTIVE

We designed this study to investigate the potential use of N-acetylcysteine (NAC) as an adjunct to alpha-blockers in the treatment of category III chronic prostatitis (CP).

METHODS

Sixty-three men with category III CP with a National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) total score of 15 or more were randomized to either the NAC treatment group or the placebo treatment group. Besides tamsulosin at a dose of 0.4 mg once daily, participants based on their allocation group received NAC or placebo at a dose of 600 mg twice daily for 12 weeks. The efficacy of the medications was assessed by measuring changes in the NIH-CPSI total score and its subscales, including pain, urinary symptoms, and quality of life.

RESULTS

Based on the general linear model analysis of the data, over the 12-week treatment, NAC+tamsulosin was statistically superior to placebo+tamsulosin in reducing the total NIH-CPSI score, pain subscore, and quality-of-life subscore (P value <.001). Further, after 12 weeks, more patients in the NAC+tamsulosin group than in the placebo+tamsulosin group met the responder criterion, defined as a decrease of at least 6 points in the NIH-CPSI total score (65.6% vs 29.0%). A more favorable outcome was also noted in the NAC+tamsulosin group regarding the number of patients reporting moderate or marked improvement in symptoms (62.5% vs 25.80%). No significant difference was seen between the groups concerning changes in urinary symptoms.

CONCLUSIONS

Our study provided clinical evidence that men with category III CP might benefit from NAC treatment. Further studies are needed for the validation of these findings.

Aqueous leaf extract from Luehea divaricata Mart. Modulates oxidative stress markers in the spinal cord of rats with neuropathic pain

ETHNOPHARMACOLOGICAL RELEVANCE

Reactive oxygen species (ROS) play an important role in neuropathic pain (i.e., pain caused by lesion or disease of the somatosensory system). We showed previously that the aqueous extract prepared from Luehea divaricata leaves, a plant explored by native ethnic groups of Brazil to treat different pathologic conditions, exhibits good antioxidant activity and induces analgesia in rats with neuropathic pain (J Ethnopharmacol, 2020; 256:112761. doi: 10.1016/j.jep.2020.112761). The effect was comparable to that of gabapentin, a drug recommended as first-line treatment for neuropathic pain. However, increasing evidence has indicated the need to accurately determine the oxidative stress level of an individual before prescribing supplemental antioxidants.

AIM OF THE STUDY

This study assessed the effects of the oral administration of aqueous extract from leaves of L. divaricata on the sciatic functional index (SFI) and spinal-cord pro-oxidant and antioxidant markers of rats with neuropathic pain.

MATERIALS AND METHODS

Placement of four loose chromic thread ligatures around the sciatic nerve produced chronic constriction injury (CCI) of the sciatic nerve, a commonly employed animal model to study neuropathic pain. Aqueous extract from leaves of L. divaricata (100, 300, 500 and 1000 mg/kg), gabapentin (50 mg/kg) and aqueous extract (500 mg/kg) + gabapentin (30 mg/kg) were administrated per gavage daily for 10 or 35 days post-CCI. Antinociception was assessed using the von Frey test while SFI showed functional recovery post-nerve lesion throughout the experimental period. At days 10 and 35 post-surgery, the lumbosacral spinal cord and a segment of the injured sciatic nerve were dissected out and used to determine lipid hydroperoxide levels and total antioxidant capacity (TAC). The spinal cord was also used to determine superoxide anion generation (SAG), hydrogen peroxide (H₂O₂) levels and total thiol content.

RESULTS

As expected, the extract, gabapentin and extract + gabapentin induced antinociception in CCI rats. While no significant functional recovery was found at 10 days post-CCI, a significant recovery was found in SFI of extract-treated CCI rats at 21 and 35 days post-CCI. A significant functional recovery was found already at day 10 post-CCI in gabapentin and gabapentin + extract-treated CCI rats. The extract treatment prevented increases in lipid hydroperoxides levels and TAC in injured sciatic nerve, which were found in this tissue of vehicle-treated rats at 10 days post-CCI. Extract also prevented an increase in SAG, H₂O₂ and lipid hydroperoxides levels in the spinal cord, which were elevated in this tissue of vehicle-treated rats at 10 and 35 days post-CCI. Extract also prevented a decrease in total thiol content and an increase in TAC in the spinal cord of CCI rats in these same time periods.

CONCLUSIONS

Aqueous extract from L. divaricata leaves was demonstrated, for the first time, to improve SFI and modulate oxidative stress markers in injured sciatic nerve and spinal cord of CCI rats. Thus, the antinociceptive effect of the extract involves modulation of oxidative stress markers in injured sciatic nerve and spinal cord.

N-acetylcysteine dose-dependently improves the analgesic effect of acetaminophen on the rat hot plate test

BACKGROUND

Acetaminophen (APAP) induced hepatotoxicity is a clinically important problem. Up to now, interventive therapy with n-acetylcysteine (NAC) has been considered as a gold-standard treatment for APAP overdose. However, no study has focused on the efficacy of these drugs' concurrent administration on probable enhancing therapeutic outcomes. Thus, this study was aimed to investigate the analgesic effect of co-administration of NAC and acetaminophen in male rats. The NAC-APAP drug formulation may demonstrate the stranger antinociceptive effect.

METHODS

Forty-eight male Sprague-Dawley rats (12-14 weeks) randomly divided into six equal groups; control, APAP (received 300 mg/kg APAP), NAC (received 600 mg/kg NAC) and APAP+ NAC groups that received simultaneously 300 mg/kg APAP with 200-600 mg/kg NAC (AN200, AN400, AN600). All administrations were done orally for once. The antinociceptive effect was recorded by measurement of latency period on a hot plate in 30, 60, and 90 min after administrations.

RESULTS

The results showed that NAC's concurrent administration with APAP, dose-dependently increased APAP analgesic effects (p< 0.0001). Moreover, NAC treatment exhibited an antinociceptive effect in 60 and 90 min, per se. The treatments had no adverse effect on liver enzymes and oxidative stress.

CONCLUSION

Co-administration of NAC with APAP can improve the antinociceptive effect of APAP. It is suggested that this compound can enhance analgesic effects of APAP and eventually lead to a reduction in acetaminophen dose. Further studies are needed to evaluate the molecular mechanism of this hyper analgesic effect.

Ameliorative Effects Of N-Acetylcysteine As Adjunct Therapy On Symptoms Of Painful Diabetic Neuropathy

Purpose

Painful diabetic neuropathy (PDN) is a variant of diabetic peripheral neuropathy which is highly prevalent and distressing in diabetic patients. Despite its high burden, the optimal treatment of PDN has remained a clinical challenge. To explain the emergence and maintenance of PDN, increasing attention has been focused on dimensions of inflammation and oxidative toxic stress (OTS). Accordingly, the aim of this study was to investigate the effects of oral N-acetylcysteine (NAC), an agent with known anti-oxidant and anti-inflammatory effects, as an adjunct therapy in patients suffering from PDN.

Patients and methods

113 eligible patients with type 2 diabetes suffering from PDN were randomly assigned to either the pregabalin + placebo or pregabalin + NAC group for 8 weeks (pregabalin at a dose of 150 mg per day, NAC and matched placebo at doses of 600 mg twice a day). Mean pain score was evaluated at baseline, week 1, 2, 4, 6, and 8 of the study based on the mean 24 hr average pain score, using an 11-point numeric rating scale (NRS). As secondary efficacy measures, mean sleep interference score (SIS) resulting from PDN, responder rates, Patient Global Impression of Change (PGIC), Clinical Global Impression of Change (CGIC), and safety were also assessed. Additionally, serum levels of total antioxidant capacity (TAC), total thiol groups (TTG), catalase activity (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), nitric oxide (NO), and malondialdehyde (MDA) were assessed at baseline and at the end of the study.

Results

Ninety patients completed the eight-week course of the study. The decrease in mean pain scores and mean sleep interference score in pregabalin + NAC group was greater in comparison with pregabalin + placebo group (p value<0.001 in both conditions). Moreover, more responders (defined as ≥50% reduction in mean pain score from baseline to end-point) were observed in the pregabalin + NAC group, in comparison with pregabalin + placebo group (72.1% vs 46.8%). More improvement in PGIC and CGIC from baseline to the end of the study was reported in pregabalin + NAC group. Oral NAC had minimal adverse effects and was well tolerated in almost all patients. Furthermore, in respect to OTS biomarkers, adjuvant NAC significantly decreased serum level of MDA and significantly increased serum levels of SOD, GPx, TAC, and TTG.

Conclusion

The pattern of results suggests that compared to placebo and over a time period of 8 weeks, adjuvant NAC is more efficacious in improving neuropathic pain associated with diabetic neuropathy than placebo. Ameliorative effects of NAC on OTS biomarkers demonstrated that NAC may alleviate painful symptoms of diabetic neuropathy, at least in part by its antioxidant effects.

Antinociceptive and anti-inflammatory effects of N-acetylcysteine and verapamil in Wistar rats

Background

Antinociceptive anti-inflammatory drugs have many adverse effects. The goal of this investigation is to study the probable anti-inflammatory and analgesic effects of verapamil and N-acetylcysteine (NAC) in experimental rats.

Methods

Adult male Wistar rats were randomly divided into 4 groups in the antinociceptive study, each containing 6 rats; the normal control group, which received saline (1 mL/kg); the diclofenac group, which received diclofenac sodium (5 mg/kg); the NAC group, which received NAC (125 mg/kg); and the verapamil group, which received verapamil (8 mg/kg). In the anti-inflammatory study, 5 groups were used, the 4 previous groups with the addition of an edema control group, received saline and were subjected to formalin test. Hot plate latency time was recorded for antinociceptive evaluation. Paw edema thickness and biochemical parameters were recorded for anti-inflammatory evaluation.

Results

Administration of NAC showed significant prolongation of hot plate latency time at 1 hour when compared to the control group while verapamil showed a significant prolongation of hot plate latency time at 1 and 2 hours when compared to the control group and NAC group values. Administration of NAC and verapamil significantly decreased paw edema thickness at 2, 4, and 8 hours when compared to edema control values. Regarding biochemical markers, NAC and verapamil significantly decreased serum nitric oxide synthase, C-reactive protein, and cyclooxygenase- 2 levels compared to the edema control value. In accordance, a marked improvement of histopathological findings was observed with both drugs.

Conclusions

NAC and verapamil have antinociceptive and anti-inflammatory effects comparable to diclofenac sodium.

Overview on the Effects of N-Acetylcysteine in Neurodegenerative Diseases

N-acetylcysteine (NAC), which is an acetylated cysteine compound, has aroused scientific interest for decades due to its important medical applications. It also represents a nutritional supplement in the human diet. NAC is a glutathione precursor and shows antioxidant and anti-inflammatory activities. In addition to the uses quoted in the literature, NAC may be considered helpful in therapies to counteract neurodegenerative and mental health diseases. Furthermore, this compound has been evaluated for its neuroprotective potential in the prevention of cognitive aging dementia. NAC is inexpensive, commercially available and no relevant side effects were observed after its administration. The purpose of this paper is to give an overview on the effects and applications of NAC in Parkinson's and Alzheimer's disorders and in neuropathic pain and stroke.