Transcutaneous Electrical Nerve Stimulation on Yongquan Acupoint Reduces CFA-Induced Thermal Hyperalgesia of Rats via Down-Regulation of ERK2 Phosphorylation and c-Fos Expression

Anatomical Exploration of the KI1 Acupoint: Implications for Medial and Lateral Plantar Nerve Stimulation

Background and Objectives: This study aims to identify the precise anatomical location and therapeutic mechanisms of the KI1 acupoint (Yongquan) in relation to foot muscles and nerves, known for treating neurological disorders and pain. Materials and Methods: Dissection of six cadavers at Chungnam National University College of Medicine examined KI1's relation to the foot's four-layer structure. Results: The KI1 acupoint was located in the superficial and deep layers of the plantar foot, adjacent to significant nerves like the medial and lateral plantar nerves. Differences in the acupoint's exact location between genders were noted, reflecting variances in foot morphology. KI1 acupuncture was found to stimulate the muscle spindles and nerve fibers essential for balance and bipedal locomotion. This stimulation may enhance sensory feedback, potentially improving cognitive functions and balance control. Conclusions: This anatomical insight into KI1 acupuncture underpins its potential in neurological therapies and pain management.

Transcutaneous Electric Nerve Stimulation in Animal Model Studies: From Neural Mechanisms to Biological Effects for Analgesia

OBJECTIVE

This systematic and meta-analysis review evaluated the transcutaneous electrical nerve stimulation (TENS)-induced action mechanisms for animal analgesia.

MATERIALS AND METHODS

Two independent investigators identified relevant articles published until February 2021 through a literature review, and a random-effects meta-analysis was performed to synthesize the results.

RESULTS

Of the 6984 studies found in the data base search, 53 full-text articles were selected and used in the systematic review. Most studies used Sprague Dawley rats (66.03%). High-frequency TENS was applied to at least one group in 47 studies, and most applications were performed for 20 minutes (64.15%). Mechanical hyperalgesia was analyzed as the primary outcome in 52.83% of the studies and thermal hyperalgesia in 23.07% of studies using a heated surface. More than 50% of the studies showed a low risk of bias on allocation concealment, random housing, selective outcome reporting, and acclimatization before the behavioral tests. Blinding was not performed in only one study and random outcome assessment in another study; acclimatization before the behavioral tests was not performed in just one study. Many studies had an uncertain risk of bias. Meta-analyses indicated no difference between low-frequency and high-frequency TENS with variations among the pain models.

CONCLUSIONS

This systematic review and meta-analysis suggests that TENS has presented a substantial scientific foundation for its hypoalgesic effect in preclinical studies for analgesia.

Transcutaneous Electrical Acupoint Stimulation Improved Preoperative Blood Pressure in Gynecological Malignant Tumor Patients With Hypertension: A Randomized, Controlled Trial

Objective

Gynecological malignant tumor patients with hypertension, even if blood pressure is well controlled, are prone to hypertension before surgery. We plan to verify the effect of transcutaneous electrical acupoint stimulation (TEAS) on stabilizing blood pressure before operation.

Methods

We enrolled 91 patients and randomly divided them into TEAS group (n=46) and control group (n=45). Patients in TEAS group received TEAS at acupoints Hegu and Neiguan. Patients in control group received transcutaneous electrical stimulation at the nonacupoint position of the upper limbs. After entering the operating room, the blood pressure before and after induction was measured. The main results were the occurrence of preinduction hypertension and postinduction hypotension.

Results

There was no difference in the general information of the two groups. There were four cases (9%) of preinduction hypertension in TEAS group and 13 cases (29%) in control group. The incidence in TEAS group was significantly lower (P=0.013). There were five cases (11%) of postinduction hypotension in TEAS group and eight cases (18%) in control group. There was no significant difference between the two groups (P=0.346). The systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) of the highest blood pressure before induction in TEAS group were lower than those in control group (P=0.002, 0.002, and 0.001). There was no difference in SBP, DBP, or MBP between the two groups on the day before the operation. There was no difference in the lowest blood pressure before operation between the two groups after induction

Conclusion

TEAS can prevent preinduction hypertension in patients with gynecological malignant tumors.

Clinical Trial Registration

http://www.chictr.org.cn/showproj.aspx?proj=143276, identifier ChiCTR2100054336.

Efficacy of Electronic Acupuncture Shoes for Chronic Low Back Pain: Double-Blinded Randomized Controlled Trial

BACKGROUND

Chronic low back pain is a common problem and is associated with high costs, including those related to health care and indirect costs due to absence at work or reduced productivity. Previous studies have demonstrated that acupuncture or electroacupuncture can relieve low back pain. Electronic acupuncture shoes (EAS) are a novel device designed in this study. This device combines the properties of acupuncture and transcutaneous electrical nerve stimulation for clinical use.

OBJECTIVE

The aim of this study was to evaluate the efficacy of EAS in patients with chronic low back pain.

METHODS

In this prospective double-blinded randomized controlled study, the data of 83 patients who experienced chronic low back pain were analyzed. Patients came to our clinic for 20 visits and underwent assessment and treatment. Patients were randomly allocated to receive either EAS plus placebo nonsteroidal anti-inflammatory drugs (NSAIDs) (EAS group, n=42) or sham EAS plus NSAIDs (NSAID group, n=41). The visual analog scale (VAS) score and range of motion were assessed at baseline, before and after each EAS treatment, and 2 weeks after the last treatment. The time for achieving pain remission was recorded. Quality of life was assessed at the 2nd, 14th, and 20th visits.

RESULTS

After 6 weeks of treatment, the treatment success rate in each visit in the EAS group was higher than that in the NSAID group, as revealed by the intention-to-treat (ITT) and per-protocol (PP) analyses, but significant differences were observed only during the 16th visit in the ITT analysis (EAS group: 31/37, 84% and NSAID group: 21/34, 62%; P=.04). The change in the VAS score from baseline in each visit in the EAS group was greater than that in the NSAID group, as revealed by the ITT and PP analyses, and significant differences were observed in the 5th visit and 9th visit in the ITT analysis (P=.048 and P=.048, respectively). Significant differences were observed in the left rotation in the 2nd visit and 4th visit (P=.049 and P=.03, respectively). No significant differences were observed in the VAS score before and after treatment in each visit and in the quality of life in both groups.

CONCLUSIONS

EAS might serve as a reliable alternative therapeutic tool for patients with chronic low back pain who are contraindicated for oral NSAIDs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02468297 https://clinicaltrials.gov/ct2/show/NCT02468297.

Effects of intraplantar administration of Complete Freund's Adjuvant (CFA) on rotarod performance in mice

BACKGROUND AND AIMS

Preclinical animal models are crucial to study pain mechanisms and assess antinociceptive effects of medications. One major problem with current animal behavioral models is their lack of face validity with human nociception and the vulnerability for false-positive results. Here, we evaluated the usefulness of rotarod as a new way to assess inflammatory nociception in rodents.

METHODS

Adult male mice were injected with saline or Complete Freund's Adjuvant (CFA) in the left hindpaws. Mechanical allodynia and rotarod performance were evaluated before and after the administration of CFA. Mechanical allodynia was measured using von Frey filaments. Long-term effect of CFA on rotarod performance was also assessed for 2 weeks.

RESULTS

Our results showed that CFA administration decreased pain threshold and increased sensitivity to von Frey filaments compared to control group. In rotarod experiments, the starting speed of the rod rotation started at four RPM, and accelerated until it reached 40 RPM in 5 min. Rotarod performance was enhanced from day to day in the control group. However, rotarod performance in CFA group was attenuated after CFA administration, which was significant after 24 h compared to vehicle. This attenuation was blocked by ibuprofen. Haloperidol administration (positive control) produced similar results to CFA administration. CFA did not produce significant attenuation of rotarod performance after 1 week post-injection.

CONCLUSIONS

Collectively, our findings could encourage the use of rotarod assay to measure acute (but not chronic) inflammatory nociception as a useful tool in rodents.

Improvement of Electroacupuncture on APP/PS1 Transgenic Mice in Spatial Learning and Memory Probably due to Expression of Aβ and LRP1 in Hippocampus

Objectives. To explore the alterations of β-amyloid (Aβ) and low density lipoprotein receptor-related protein-1 (LRP1) in APP/PS1 mice after electroacupuncture (EA) treatment and further to explore the mechanism. Methods. Forty 6-month-old APP/PS1 mice were randomly divided into a model group and an EA group, with twenty wild-type mice used as a normal control group. Mice in the EA group were treated with EA at GV 20 (băi huì) and bilateral KI 1 (yŏng quán) acupoints for 6 weeks. The Morris water maze was applied to assess the spatial memory in behavior. Immunohistochemistry (IHC), ELISA, Western blotting, and so forth were used to observe the expression of LRP1 and Aβ. Results. The Morris water maze test showed that, compared with the normal control group, the model group's learning and memory capabilities were significantly decreased (P < 0.05; P < 0.01). The EA group was reversed (P < 0.05; P < 0.01). The hippocampal expression of Aβ in the EA group was significantly decreased compared to the model group (P < 0.01). The expression of LRP1 in the model group was significantly lower than that in the normal control group (P < 0.01); the expression in the EA group was significantly higher than that in the model group (P < 0.01). Conclusions. EA therapy can improve the learning and memory capabilities of APP/PS1 mice. The underlying mechanism may lie in the upregulation of an Aβ transport receptor and LRP1.

Effects of transcutaneous acupoint electrical stimulation on the imbalance of Th1, Th2, Th17 and Treg cells following thoracotomy of patients with lung cancer

An imbalance in the various T lymphocytes, including T-helper (Th)₁, Th₂ and Th₁₇ cells, and regulatory T (T_reg) cells, has been associated with immune dysfunction, and may occur following thoracotomy of patients with lung cancer. The use of transcutaneous acupoint electrical stimulation (TAES) has previously been demonstrated to exert immunoregulatory effects; therefore, the present study aimed to evaluate whether TAES was able to attenuate postoperative immune suppression in patients with lung cancer. Thoracic surgical patients with lung cancer (n=27) underwent TAES (frequency, 2/100 Hz; intensity, 4-12 mA) at the bilateral large intestine 4, pericardium 6, small intestine 3 and San Jiao 6 acupuncture points for 30 min, prior to incision, and at 20, 44, 68, 92 and 116 h following thoracotomy. The number of Th₁, Th₂, Th₁₇ and T_reg cells, and the protein and mRNA expression levels of related cytokines were measured by flow cytometry, ELISA and polymerase chain reaction, respectively. The balance of Th₁, Th₂, Th₁₇ and T_reg cells in the peripheral blood of patients with lung cancer was disrupted following thoracotomy. TAES administration increased the percentage of Th₁ and Th₁₇ cells, the protein expression levels of interleukin (IL)-2 and interferon-γ, the mRNA expression levels of T-bet and RAR-related orphan receptor-γt, and decreased the percentage of Th₂ cells, IL-10 protein expression levels, and GATA binding protein 3 mRNA expression levels. The results of the present study demonstrated that TAES was able to partially attenuate the postoperative immune depression of patients with lung cancer, by regulating the balance of Th₁, Th₂, Th₁₇ and T_reg cells, and the expression levels of related cytokines and transcription factors; therefore, TAES may be considered to be a promising strategy for treating postoperative immune dysfunction in patients with lung cancer.

Short-term effect of acute and repeated urinary bladder inflammation on thigmotactic behaviour in the laboratory rat

Understanding the non-sensory components of the pain experience is crucial to developing effective treatments for pain conditions. Chronic pain is associated with increased incidence of anxio-depressive disorders, and patients often report feelings of vulnerability which can decrease quality of life. In animal models of pain, observation of behaviours such as thigmotaxis can be used to detect such affective disturbances by exploiting the influence of nociceptive stimuli on the innate behavioural conflict between exploration of a novel space and predator avoidance behaviour. This study investigates whether acute and repeated bladder inflammation in adult female Wistar rats increases thigmotactic behaviour in the open field paradigm, and aims to determine whether this correlates with activation in the central amygdala, as measured by c-Fos immunoreactivity. Additionally, up-regulation of inflammatory mediators in the urinary bladder was measured using RT-qPCR array featuring 92 transcripts to examine how local mediators change under experimental conditions. We found acute but not repeated turpentine inflammation of the bladder increased thigmotactic behaviour (decreased frequency of entry to the inner zone) in the open field paradigm, a result that was also observed in the catheter-only instrumentation group. Decreases in locomotor activity were also observed in both models in turpentine and instrumentation groups. No differences were observed in c-Fos activation, although a general increased in activation along the rostro-caudal axis was seen. Inflammatory mediator up-regulation was greatest following acute inflammation, with CCL12, CCL7, and IL-1β significantly up-regulated in both conditions when compared to naïve tissue. These results suggest that acute catheterisation, with or without turpentine inflammation, induces affective alterations detectable in the open field paradigm accompanied by up-regulation of multiple inflammatory mediators.

Decreased low back pain intensity and differential gene expression following Calmare®: results from a double-blinded randomized sham-controlled study

In this double-blinded, randomized controlled trial we evaluated the effects of Calmare®, a non-invasive neurocutaneous electrical pain intervention, on lower back pain intensity as measured by the "worst" pain score and on pain interference using the Brief Pain Inventory-Short Form, on measures of pain sensitivity assessed by quantitative sensory testing, and on mRNA expression of pain sensitivity genes. Thirty participants were randomized to receive up to 10 sessions of Calmare® treatment (n = 15) or a sham treatment (n = 15) using the same device at a non-therapeutic threshold. At 3 weeks after conclusion of treatment, compared with the sham group, the Calmare® group reported a significant decrease in the "worst" pain and interference scores. There were also significant differences in pain sensitivity and differential mRNA expression of 17 pain genes, suggesting that Calmare® can be effective in reducing pain intensity and interference in individuals with persistent low back pain by altering the mechanisms of enhanced pain sensitivity. Further study of long-term pain outcomes, particularly functional status, analgesic use and health care utilization, is warranted.

Transcutaneous electric acupoint stimulation reduces intra-operative remifentanil consumption and alleviates postoperative side-effects in patients undergoing sinusotomy: a prospective, randomized, placebo-controlled trial

BACKGROUND

Although opioids are widely used as analgesics in general anaesthesia, they have unpleasant side-effects and can delay postoperative recovery. Acupuncture and related techniques are effective for acute and chronic pain, and reduces some side-effects. We assessed the effect of transcutaneous electric acupoint stimulation (TEAS) on intra-operative remifentanil consumption and the incidences of anaesthesia-related side-effects.

METHODS

Sixty patients undergoing sinusotomy were randomly assigned to TEAS or control group. TEAS consisted of 30 min of stimulation (6-9 mA, 2/10 Hz) on the Hegu (LI4), Neiguan (PC6), and Zusanli (ST36) before anaesthesia. The patients in the control group had the electrodes applied, but received no stimulation. Bispectral index was used to monitor the depth of anaesthesia. Perioperative haemodynamics were recorded, and peripheral blood samples were collected to measure the levels of mediators of surgical stress. The primary end point was intraoperative remifentanil consumption and the secondary endpoints were recovery quality and anaesthesia-related side-effects.

RESULTS

Patients in the TEAS group required 39% less remifentanil during surgery than controls [0.0907 (SD 0.026) μg kg(-1) min(-1) vs 0.051 (0.018) μg kg(-1) min(-1)]. There were no differences in intra-operative haemodynamics or surgical stress between groups. However, the time to extubation and recall in the control group was 16.8 (6.8) min and 23.0 (5.0) min, respectively, significantly longer than that in the TEAS group (P<0.01). TEAS also decreased the incidence of dizziness and pruritus within the first 24 h after surgery (P<0.01).

CONCLUSION

The use of TEAS significantly reduced intra-operative remifentanil consumption and alleviated postoperative side-effects in patients undergoing sinusotomy.

CLINICAL TRIAL REGISTRATION

The trial was registered at clinicaltrials.gov (NCT01700855).

Repeated forced swim stress enhances CFA-evoked thermal hyperalgesia and affects the expressions of pCREB and c-Fos in the insular cortex

Stress affects brain activity and promotes long-term changes in multiple neural systems. Exposure to stressors causes substantial effects on the perception and response to pain. In several animal models, chronic stress produces lasting hyperalgesia. The insular (IC) and anterior cingulate cortices (ACC) are the regions exhibiting most reliable pain-related activity. And the IC and ACC play an important role in pain modulation via the descending pain modulatory system. In the present study we examined the expression of phospho-cAMP response element-binding protein (pCREB) and c-Fos in the IC and ACC after forced swim stress (FS) and complete Freund's adjuvant (CFA) injection to clarify changes in the cerebral cortices that affect the activity of the descending pain modulatory system in the rats with stress-induced hyperalgesia. FS (day 1, 10min; days 2-3, 20min) induced an increase in the expression of pCREB and c-Fos in the anterior IC (AIC). CFA injection into the hindpaw after the FS shows significantly enhanced thermal hyperalgesia and induced a decrease in the expression of c-Fos in the AIC and the posterior IC (PIC). Quantitative image analysis showed that the numbers of c-Fos-immunoreactive neurons in the left AIC and PIC were significantly lower in the FS+CFA group (L AIC, 95.9±6.8; L PIC, 181.9±23.1) than those in the naive group (L AIC, 151.1±19.3, p<0.05; L PIC, 274.2±37.3, p<0.05). These findings suggest a neuroplastic change in the IC after FS, which may be involved in the enhancement of CFA-induced thermal hyperalgesia through dysfunction of the descending pain modulatory system.

Decreased intracellular GABA levels contribute to spinal cord stimulation-induced analgesia in rats suffering from painful peripheral neuropathy: the role of KCC2 and GABA(A) receptor-mediated inhibition

Elevated spinal extracellular γ-aminobutyric acid (GABA) levels have been described during spinal cord stimulation (SCS)-induced analgesia in experimental chronic peripheral neuropathy. Interestingly, these increased GABA levels strongly exceeded the time frame of SCS-induced analgesia. In line with the former, pharmacologically-enhanced extracellular GABA levels by GABA(B) receptor agonists in combination with SCS in non-responders to SCS solely could convert these non-responders into responders. However, similar treatment with GABA(A) receptor agonists and SCS is known to be less efficient. Since K⁺ Cl⁻ cotransporter 2 (KCC2) functionality strongly determines proper GABA(A) receptor-mediated inhibition, both decreased numbers of GABA(A) receptors as well as reduced KCC2 protein expression might play a pivotal role in this loss of GABA(A) receptor-mediated inhibition in non-responders. Here, we explored the mechanisms underlying both changes in extracellular GABA levels and impaired GABA(A) receptor-mediated inhibition after 30 min of SCS in rats suffering from partial sciatic nerve ligation (PSNL). Immediately after cessation of SCS, a decreased spinal intracellular dorsal horn GABA-immunoreactivity was observed in responders when compared to non-responders or sham SCS rats. One hour later however, GABA-immunoreactivity was already increased to similar levels as those observed in non-responder or sham SCS rats. These changes did not coincide with alterations in the number of GABA-immunoreactive cells. C-Fos/GABA double-fluorescence clearly confirmed a SCS-induced activation of GABA-immunoreactive cells in responders immediately after SCS. Differences in spinal dorsal horn GABA(A) receptor-immunoreactivity and KCC2 protein levels were absent between all SCS groups. However, KCC2 protein levels were significantly decreased compared to sham PSNL animals. In conclusion, reduced intracellular GABA levels are only present during the time frame of SCS in responders and strongly point to a SCS-mediated on/off GABAergic release mechanism. Furthermore, a KCC2-dependent impaired GABA(A) receptor-mediated inhibition seems to be present both in responders and non-responders to SCS due to similar KCC2 and GABA(A) receptor levels.