Lumbo-pelvic proprioception in sitting is impaired in subgroups of low back pain-But the clinical utility of the differences is unclear. A systematic review and meta-analysis

Influence of short bouts of stair climbing on young adults during prolonged sitting on posture, discomfort, and musculoskeletal performance outcomes: a counterbalanced pilot randomised crossover trial

Prolonged sitting is postulated to influence musculoskeletal performance (cervical flexor endurance, balance, and agility), discomfort and alter cervical spine angles during work-based computer use. Stair climbing breaks may be a great addition at typical and home offices however remain unexplored for its impact on musculoskeletal performance. In our counterbalanced pilot crossover trial, 24 adults were randomised to three interventions: (1) prolonged sitting, (2) interrupted by 2 min of self-paced, and (3) externally paced stair climbing for 2 h. Cervical spine angles were measured every 30 min while balance, agility, endurance, and discomfort were assessed before and after 120 min. Stair climbing interruptions have favourable effects on agility (F = 8.12, p = 0.009, ηp2 = 0.26) and musculoskeletal discomfort, but failed to improve other musculoskeletal outcomes associated with prolonged sitting. Brief stair climbing interruptions are effective in improving discomfort and agility while pragmatic trials are warranted for translated effects.

Potential of a New, Flexible Electrode sEMG System in Detecting Electromyographic Activation in Low Back Muscles during Clinical Tests: A Pilot Study on Wearables for Pain Management

BACKGROUND

While low back pain (LBP) is the leading cause of disability worldwide, its clinical objective assessment is currently limited. Part of this syndrome arises from the abnormal sensorimotor control of back muscles, involving increased muscle fatigability (i.e., assessed with the Biering-Sorensen test) and abnormal muscle activation patterns (i.e., the flexion-extension test). Surface electromyography (sEMG) provides objective measures of muscle fatigue development (median frequency drop, MDF) and activation patterns (RMS amplitude change). This study therefore assessed the sensitivity and validity of a novel and flexible sEMG system (NSS) based on PEVA electrodes and potentially embeddable in textiles, as a tool for objective clinical LBP assessment.

METHODS

Twelve participants wearing NSS and a commercial laboratory sEMG system (CSS) performed two clinical tests used in LBP assessment (Biering-Sorensen and flexion-extension). Erector spinae muscle activity was recorded at T12-L1 and L4-L5.

RESULTS

NSS showed sensitivity to sEMG changes associated with fatigue development and muscle activations during flexion-extension movements (p < 0.05) that were similar to CSS (p > 0.05). Raw signals showed moderate cross-correlations (MDF: 0.60-0.68; RMS: 0.53-0.62). Adding conductive gel to the PEVA electrodes did not influence sEMG signal interpretation (p > 0.05).

CONCLUSIONS

This novel sEMG system is promising for assessing electrophysiological indicators of LBP during clinical tests.

Tactile acuity and active joint repositioning sense in individuals with and without chronic low back pain: a cross-sectional study

BACKGROUND

Sensorimotor dysfunction, as measured by tactile acuity and active joint repositioning, has been identified as a contributing factor of chronic low back pain (CLBP). Existing research suggests that further research is necessary to improve the characterization of sensorimotor perception in patients with CLBP.

OBJECTIVES

The main aim is to investigate whether tactile acuity and repositioning errors differ between individuals with CLBP and controls without CLBP. A secondary aim was to investigate the association between age, body mass index (BMI) and physical activity, and tactile acuity and repositioning sense.

METHODS

Cross-sectional study. Sixty-eight participants (36 with, 32 without CLBP) were examined. Two-Point Discrimination (TPD) test (four measures: horizontal and vertical run, left and right side) and Active Joint Reposition Sense (AJRS) test (2 directions: to flexion and to extension) were used.

RESULTS

No differences were found for TPD (right horizontal run: p = .069; left horizontal run: p = .066; right vertical run: p = .933; left vertical run: p = .285) or AJRS (flexion: p = .792; extension: p = .956) between participants with and without CLBP. Older subjects had significantly worse tactile acuity (3 sites, p = .018, p = .004, p = .041) and worse repositioning sense (2 directions, p = .026, p = .040,) than younger subjects. Individuals with BMI ≥ 25 had significantly worse TPD compared to individuals with normal weight (2 sites, p = .028, p = .020).

CONCLUSIONS

Individuals with CLBP did not have impaired tactile and repositioning accuracy when compared to controls without CLBP. Future studies comparing sensorimotor performance should consider age and BMI as potential confounding factors.

Clinically assessed lumbopelvic sensorimotor control tests in low back pain: are they actually valid? A systematic review according to COSMIN guidelines

BACKGROUND

Impairments in lumbopelvic sensorimotor control (SMC) are thought to be one of the underlying mechanisms for the recurrence and persistence of low back pain (LBP). As such, lumbopelvic SMC tests are frequently included in the clinical examination of patients with LBP.

OBJECTIVE

To evaluate convergent and known-groups validity of clinically assessed lumbopelvic SMC tests in patients with LBP according to COSMIN guidelines.

DESIGN

Systematic review METHODS: Five electronic databases were searched until December 2023. Studies examining convergent or known-groups validity of lumbopelvic SMC tests assessed via inspection or palpation in patients with LBP were included. Known-groups validity had to be assessed between patients with LBP and pain-free persons. Two independent researchers appraised risk of bias and quality of evidence (QoE) using the COSMIN Risk of Bias checklist and modified GRADE approach, respectively. Results for known-groups validity were reported separately for single tests and test-clusters.

RESULTS

Twelve studies (946 participants) were included. Three studies investigated convergent validity of three single tests. Regarding known-groups validity, six studies evaluated six single tests and four studies investigated two test-clusters. For only one test, both convergent and known-groups were assessed. The QoE for tests showing sufficient convergent or known-groups validity was (very) low, whereas QoE was moderate for single tests or test-clusters with insufficient known-groups validity.

CONCLUSION

All clinically assessed lumbopelvic SMC tests with sufficient convergent or known-groups validity had (very) low QoE. Therefore, test outcomes should be interpreted cautiously and strong reliance on these outcomes for clinical decision-making can currently not be recommended.

Poor lumbar spine coordination in acute low back pain predicts persistent long-term pain and disability

PURPOSE

Sitting balance on an unstable surface requires coordinated out-of-phase lumbar spine and provides sufficient challenge to expose quality of spine control. We investigated whether the quality of spine coordination to maintain balance in acute low back pain (LBP) predicts recovery at 6 months.

METHODS

Participants in an acute LBP episode (n = 94) underwent assessment of sitting balance on an unstable surface. Seat, hip and spine (lower lumbar, lumbar, upper lumbar, thoracic) angular motion and force plate data were recorded. Coordination between the seat and hip/spine segments to maintain balance was quantified in the frequency domain to evaluate coordination (coherence) and relative timing (phase angle: in-phase [segments move together]; out-of-phase [segments move opposite]). Center of pressure (CoP) and upper thorax motion assessed overall balance performance. Hip and spine coordination with the seat were compared between those who did not recover (increased/unchanged pain/disability), partially recovered (reduced pain/disability) or recovered (no pain and disability) at 6 months.

RESULTS

In both planes, coherence between the seat and lower lumbar spine was lower (and in-phase-unhelpful for balance) at baseline in those who did not recover than those who recovered. Coherence between the seat and hip was higher in partially recovered in both planes, suggesting compensation by the hip. LBP groups had equal overall balance performance (CoP, upper thorax motion), but non-recovery groups used a less optimal strategy that might have consequences for long-term spine health.

CONCLUSION

These longitudinal data revealed that individuals with compromised contribution of the lumbar spine to the balance during unstable sitting during acute LBP are less likely to recover.

Lower Limb Proprioception in Low Back Pain and Its Relationship With Voluntary Postural Control

This study aimed to investigate whether patients with low back pain (LBP) had impaired lower limb proprioception and its association with somatosensory acuity. Thirty patients with LBP and 30 asymptomatic people volunteered, using Sway Discrimination Apparatus tests to assess somatosensory acuity during voluntary anteroposterior and mediolateral postural sway. Results showed significantly reduced somatosensory acuity in mediolateral sway in LBP patients (p = 0.005) with ankle, knee, and hip proprioception showing significantly impairment compared to asymptomatic controls (all p ≤ 0.012). Regression analysis showed that ankle and hip proprioception were significantly associated with somatosensory perception (0.001 ≤ p ≤ 0.026, 0.067 ≤ R2≤ 0.235). Overall, findings suggested a global deterioration of lower limb proprioception in LBP patients, with ankle and hip proprioception playing crucial role in somatosensory perception.

Coordination of hip and spine in individuals with acute low back pain during unstable sitting

BACKGROUND CONTEXT

Trunk postural control differs between individuals with and without chronic low back pain (LBP). Whether this corresponds to differences in hip/spine coordination during the early acute phase of LBP (ALBP) is unclear.

PURPOSE

To compare hip/spine coordination in relation to seat movements between individuals with and without ALBP when balancing on an unstable seat and to identify coordination strategies to maintain balance using cluster analysis.

STUDY DESIGN/SETTING

Cross-sectional observational study.

PATIENT SAMPLE

ALBP (n=130) and pain-free (n=72) individuals.

OUTCOME MEASURES

Frequency domain measures to evaluate hip/spine coordination (amplitude spectrum, phase angle, and coherence) and time-series measures to assess overall balance performance (center of pressure [CoP] reflecting the amount of seat movements, upper thorax motion as a surrogate for head motion).

METHODS

Participants maintained balance while sitting on a seat fixed to a hemisphere. Seat, hip, and spine (lower lumbar, lumbar, upper lumbar, and thoracic) angular motion and force plate data were recorded.

RESULTS

Overall, seat/CoP movements (amplitude spectrum and RMSdisplacement) were greater (in both planes) and sagittal coordination (coherence) between the hip or lower spine and seat movements was lower in ALBP than controls. Cluster analysis using coherence data revealed different coordination strategies to maintain balance. Separate clusters used a "lower lumbar strategy" and "hip strategy" in the sagittal plane, and a "lower and upper lumbar strategy" and "lower lumbar strategy" in the frontal plane. A cluster using a "low coherence strategy" in both planes was also identified.

CONCLUSIONS

Hip and lower spine coordination was less in individuals with ALBP in conjunction with a lower quality of overall balance performance. However, interpretation of the relationship between coherence and overall balance performance was not straightforward. Clusters in both the ALBP group and the control group adopted a low coherence strategy, and this was not consistently related to poor overall balance performance. This suggests overall balance performance cannot be inferred from coherence alone and requires consideration of interaction of other different features.

The associations between lumbar proprioception and postural control during and after calf vibration in people with and without chronic low back pain

The relationships of lumbar proprioception with postural control have not been clarified in people with chronic low back pain. This study aimed to compare the associations between lumbar proprioception and postural control in response to calf vibration in individuals with and without chronic low back pain. In this study, we recruited twenty patients with chronic low back pain (CLBP group) and twenty healthy control subjects (HC group) aged between 18 and 50 years. This study was a cross-sectional study and completed from May 2022 to October 2022. The passive joint repositioning sense (PJRS) test for two positions (15° and 35°) were used to assess lumbar proprioception and expressed as the mean of reposition error (RE). Postural control was tested by adding and removing calf vibration while standing on a stable force plate with eyes closed. The sway velocity in the anterior-posterior (AP) direction of center of pressure (COP) data with a window of 15s epoch at baseline, during and after calf vibration was used to evaluate postural control. Mann-Whitney U-tests were used to compare the difference of lumbar proprioception between two groups, and the independent t-tests were used to compare the difference of postural control at baseline and during vibration, and a mixed design ANOVA was used to compare the difference of postural control during post-perturbation. In addition, to explore the association between postural control and lumbar proprioception and pain intensity, Spearman's correlations were used for each group. The major results are: (1) significantly higher PJRS on RE of 15° (CLBP: 95% CI [2.03, 3.70]; HC: 95% CI [1.03, 1.93]) and PJRS on RE of 35° (CLBP: 95% CI [2.59, 4.88]; HC: 95% CI [1.07, 3.00]) were found in the CLBP group; (2) AP velocity was not different between the CLBP group and the HC group at baseline and during calf vibration. However, AP velocity was significantly larger in the CLBP group compared with the HC group at epoch 2-14 after calf vibration, and AP velocity for the CLBP group took a longer time (23 epochs) to return to the baseline after calf vibration compared with the HC group (9 epochs); (3) lumbar proprioception represented by PJRS on RE of 15°correlated negatively with AP velocity during and after vibration for the HC group. Within the CLBP group, no significant relationships between PJRS on RE for two positions (15° and 35°) and AP velocity in any postural phases were found. In conclusion, the CLBP group has poorer lumbar proprioception, slower proprioceptive reweighting and impaired postural control after calf vibration compared to the HC group. Lumbar proprioception offers different information on the control strategy of standing control for individuals with and without CLBP in the situations with proprioceptive disturbance. These results highlight the significance of assessing lumbar proprioception and postural control in CLBP patients.

Impact of lumbar delayed-onset muscle soreness on postural stability in standing postures

BACKGROUND

Similar impact on proprioception has been observed in participants with lumbar delayed-onset muscle soreness (DOMS) and chronic low back pain (LBP), raising questions about the relevance of lumbar DOMS as a suitable pain model for LBP when assessing back pain-related postural stability changes.

RESEARCH QUESTION

Does lumbar DOMS impact postural stability?

METHODS

Twenty healthy adults participated in this experimental study and underwent a posturographic examination before and 24 to 36 h after a protocol designed to induce lumbar DOMS. Posturographic examination was assessed during quiet standing on both feet with eyes opened (EO), with eyes closed (EC), and on one-leg (OL) standing with eyes opened. Postural stability was assessed through center of pressure (COP) parameters (COP area, velocity, root mean square, mean power frequency) which were compared using repeated measure ANOVA. Moreover, pain, soreness and pressure pain threshold (PPT) on specific muscles were assessed.

RESULTS

There was a significant main effect of the postural condition on all COP variables investigated. More specifically, each COP variable reached a significantly higher value in the OL stance condition than in both EO and EC bipedal conditions (all with p < 0.001). In addition, the COP velocity and the mean power frequency along the anteroposterior direction both reached a significantly higher value in EC than in EO (p < 0.001). In contrast, there was no significant main effect of the DOMS nor significant DOMS X postural condition interaction on any of the COP variables. There was a significant decrease in the PPT value for both the left and right erector spinae muscles, as well as the left biceps femoris.

SIGNIFICANCE

Lumbar DOMS had no impact on postural stability, which contrasts findings in participants with clinical LBP. Although DOMS induces similar trunk sensorimotor adaptations to clinical LBP, it does not appear to trigger similar postural stability adaptations.

Kinematic changes of the trunk and lower limbs during voluntary lateral sway postural control in adults with low back pain

Introduction: Voluntary lateral weight shifting is essential for gait initiation. However, kinematic changes during voluntary lateral weight shifting remain unknown in people with low back pain (LBP). This study aims to explore the differences in kinematics and muscle activation when performing a voluntary lateral weight shifting task between patients with LBP and asymptomatic controls without pain. Methods: Twenty-eight participants volunteered in this study (14 in both the LBP group and the control group). The Sway Discrimination Apparatus (SwayDA) was used to generate a postural sway control task, mimicking lateral weight shifting movements when initiating gait. Kinematic parameters, including range of motion (ROM) and standard deviation of ROM (Std-ROM) of the lumbar spine, pelvis, and lower limb joints, were recorded using a motion capture system during lateral weight shifting. The electroactivity of the trunk and lower limb muscles was measured through surface electromyography using root mean square (RMS). The significant level was 0.05. An independent t-test was employed to compare kinematic parameters, and muscle activation between the LBP group and the control group. A paired-sample t-test, adjusted with Bonferroni correction (significant level of 0.025), was utilized to examine differences between the ipsilateral weight shifting towards side (dominant side) and the contralateral side. Results: The results of kinematic parameters showed significantly decreased ROM and std-ROM of the ipsilateral hip in the transverse plane (tROM = -2.059, p = 0.050; tstd-ROM = -2.670, p = 0.013), as well as decreased ROM of the ipsilateral knee in the coronal plane (t = -2.148, p = 0.042), in the LBP group compared to the control group. For the asymptomatic controls, significantly larger ROM and ROM-std were observed in the hip and knee joints on the ipsilateral side in contrast to the contralateral side (3.287 ≤ t ≤ 4.500, 0.001 ≤ p≤ 0.006), but no significant differences were found between the two sides in the LBP group. In addition, the LBP group showed significantly lower RMS of the biceps femoris than the control group (tRMS = -2.186, p = 0.044). Discussion: Patients with LBP showed a conservative postural control pattern, characterized by reduced ROM of ipsilateral joints and diminished activation of the biceps femoris. These findings suggested the importance of voluntary postural control assessment and intervention to maximize recovery.

Trunk postural control during unstable sitting among individuals with and without low back pain: A systematic review with an individual participant data meta-analysis

INTRODUCTION

Sitting on an unstable surface is a common paradigm to investigate trunk postural control among individuals with low back pain (LBP), by minimizing the influence lower extremities on balance control. Outcomes of many small studies are inconsistent (e.g., some find differences between groups while others do not), potentially due to confounding factors such as age, sex, body mass index [BMI], or clinical presentations. We conducted a systematic review with an individual participant data (IPD) meta-analysis to investigate whether trunk postural control differs between those with and without LBP, and whether the difference between groups is impacted by vision and potential confounding factors.

METHODS

We completed this review according to PRISMA-IPD guidelines. The literature was screened (up to 7th September 2023) from five electronic databases: MEDLINE, CINAHL, Embase, Scopus, and Web of Science Core Collection. Outcome measures were extracted that describe unstable seat movements, specifically centre of pressure or seat angle. Our main analyses included: 1) a two-stage IPD meta-analysis to assess the difference between groups and their interaction with age, sex, BMI, and vision on trunk postural control; 2) and a two-stage IPD meta-regression to determine the effects of LBP clinical features (pain intensity, disability, pain catastrophizing, and fear-avoidance beliefs) on trunk postural control.

RESULTS

Forty studies (1,821 participants) were included for the descriptive analysis and 24 studies (1,050 participants) were included for the IPD analysis. IPD meta-analyses revealed three main findings: (a) trunk postural control was worse (higher root mean square displacement [RMSdispl], range, and long-term diffusion; lower mean power frequency) among individuals with than without LBP; (b) trunk postural control deteriorated more (higher RMSdispl, short- and long-term diffusion) among individuals with than without LBP when vision was removed; and (c) older age and higher BMI had greater adverse impacts on trunk postural control (higher short-term diffusion; longer time and distance coordinates of the critical point) among individuals with than without LBP. IPD meta-regressions indicated no associations between the limited LBP clinical features that could be considered and trunk postural control.

CONCLUSION

Trunk postural control appears to be inferior among individuals with LBP, which was indicated by increased seat movements and some evidence of trunk stiffening. These findings are likely explained by delayed or less accurate corrective responses.

SYSTEMATIC REVIEW REGISTRATION

This review has been registered in PROSPERO (registration number: CRD42021124658).

The Role of Back Muscle Dysfunctions in Chronic Low Back Pain: State-of-the-Art and Clinical Implications

Changes in back muscle function and structure are highly prevalent in patients with chronic low back pain (CLBP). Since large heterogeneity in clinical presentation and back muscle dysfunctions exists within this population, the potential role of back muscle dysfunctions in the persistence of low back pain differs between individuals. Consequently, interventions should be tailored to the individual patient and be based on a thorough clinical examination taking into account the multidimensional nature of CLBP. Considering the complexity of this process, we will provide a state-of-the-art update on back muscle dysfunctions in patients with CLBP and their implications for treatment. To this end, we will first give an overview of (1) dysfunctions in back muscle structure and function, (2) the potential of exercise therapy to address these dysfunctions, and (3) the relationship between changes in back muscle dysfunctions and clinical parameters. In a second part, we will describe a framework for an individualised approach for back muscle training in patients with CLBP.

The sensorimotor theory of pathological pain revisited

Harris (1999) proposed that pain can arise in the absence of tissue damage because changes in the cortical representation of the painful body part lead to incongruences between motor intention and sensory feedback. This idea, subsequently termed the sensorimotor theory of pain, has formed the basis for novel treatments for pathological pain. Here we review the evidence that people with pathological pain have changes to processes contributing to sensorimotor function: motor function, sensory feedback, cognitive representations of the body and its surrounding space, multisensory processing, and sensorimotor integration. Changes to sensorimotor processing are most evident in the form of motor deficits, sensory changes, and body representations distortions, and for Complex Regional Pain Syndrome (CRPS), fibromyalgia, and low back pain. Many sensorimotor changes are related to cortical processing, pain, and other clinical characteristics. However, there is very limited evidence that changes in sensorimotor processing actually lead to pain. We therefore propose that the theory is more appropriate for understanding why pain persists rather than how it arises.

Feedback on Trunk Movements From an Electronic Game to Improve Postural Balance in People With Nonspecific Low Back Pain: Pilot Randomized Controlled Trial

Background

Postural balance is compromised in people with low back pain, possibly by changes in motor control of the trunk. Augmenting exercising interventions with sensor-based feedback on trunk posture and movements might improve postural balance in people with low back pain.

Objective

We hypothesized that exercising with feedback on trunk movements reduces sway in anterior-posterior direction during quiet standing in people with low back pain. Secondary outcomes were lumbar spine and hip movement assessed during box lift and waiter bow tasks, as well as participant-reported outcomes. Adherence to the exercising intervention was also examined.

Methods

A randomized controlled trial was conducted with the intervention group receiving unsupervised home exercises with visual feedback using the Valedo Home, an exergame based on 2 inertial measurement units. The control group received no intervention. Outcomes were recorded by blinded staff during 4 visits (T1-T4) at University Hospital Zurich. The intervention group performed 9 sessions of 20 minutes in the 3 weeks between T2 and T3 and were instructed to exercise at their own convenience between T3 and T4. Postural balance was assessed on a force platform. Lumbar spine and hip angles were obtained from 3 inertial measurement units. The assessments included pain intensity, disability, quality of life, and fear of movement questionnaires.

Results

A total of 32 participants with nonspecific low back pain completed the first assessment T1, and 27 (84%) participants were randomized at T2 (n=14, 52% control and n=13, 48% intervention). Intention-to-treat analysis revealed no significant difference in change in anterior-posterior sway direction during the intervention period with a specified schedule (T2-T3) between the groups (W=99; P=.36; r=0.07). None of the outcomes showed significant change in accordance with our hypotheses. The intervention group completed a median of 61% (55/90; range 2%-99%) of the exercises in the predefined training program. Adherence was higher in the first intervention period with a specified schedule.

Conclusions

The intervention had no significant effect on postural balance or other outcomes, but the wide range of adherence and a limited sample size challenged the robustness of these conclusions. Future work should increase focus on improving adherence to digital interventions.

Trial Registration

ClinicalTrials.gov NCT04364243; https://clinicaltrials.gov/ct2/show/NCT04364243

International Registered Report Identifier (IRRID)

RR2-10.2196/26982

Muscle spindles of the multifidus muscle undergo structural change after intervertebral disc degeneration

Purpose

Proprioceptive deficits are common in low back pain. The multifidus muscle undergoes substantial structural change after back injury, but whether muscle spindles are affected is unclear. This study investigated whether muscle spindles of the multifidus muscle are changed by intervertebral disc (IVD) degeneration in a large animal model.

Methods

IVD degeneration was induced by partial thickness annulus fibrosus lesion to the L3-4 IVD in nine sheep. Multifidus muscle tissue at L4 was harvested at six months after lesion, and from six age-/sex-matched naïve control animals. Muscle spindles were identified in Van Gieson’s-stained sections by morphology. The number, location and cross-sectional area (CSA) of spindles, the number, type and CSA of intrafusal fibers, and thickness of the spindle capsule were measured. Immunofluorescence assays examined Collagen I and III expression.

Results

Multifidus muscle spindles were located centrally in the muscle and generally near connective tissue. There were no differences in the number or location of muscle spindles after IVD degeneration and only changes in the CSA of nuclear chain fibers. The thickness of connective tissue surrounding the muscle spindle was increased as was the expression of Collagen I and III.

Conclusion

Changes to the connective tissue and collagen expression of the muscle spindle capsule are likely to impact their mechanical properties. Changes in capsule stiffness may impact the transmission of length change to muscle spindles and thus transduction of sensory information. This change in muscle spindle structure may explain some of the proprioceptive deficits identified with low back pain.

Vitamin D inhibits TNF-α induced apoptosis of human nucleus pulposus cells through regulation of NF-kB signaling pathway

BACKGROUND

To observe the effects of vitamin D on the apoptotic human nucleus pulposus cells under tumor necrosis factor-α (TNF-α) treatment.

METHODS

The gene expression data was downloaded from the NCBI Gene Expression Omnibus (GEO) database ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE34095 ). Differentially expressed genes between degenerative disc and non-degenerative disc were performed by R software. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway enrichment analyses were performed using The Database for Annotation, Visualization and Integrated Discovery (DAVID). Then, the human nucleus pulposus tissue was harvested from 12 patients according to the modified Pfirrmann classification and human nucleus pulposus cells were obtained from digestion of herniated nucleus pulposus tissue. The collected nucleus pulposus cells were treated with different concentration of TNF-α, and cellular apoptosis was measured by flow cytometry. Then, human nucleus pulposus cells were divided into following groups: normal culture medium, TNF-α treated, TNF-α, and vitamin D-treated groups. Cellular apoptosis rate was quantified by flow cytometry. Protein expression of p-p65, p65, and IkBa was detected with western blot analysis.

RESULTS

A total of 536 differentially expressed genes were identified through bioinformatic analysis. KEGG pathway revealed that NF-kB signaling pathway was involved in the process of disc degeneration. In the NP cell cultures, vitamin D significantly increased cell proliferation potency. Furthermore, vitamin D inhibited TNF-α induced apoptosis of human nucleus pulposus cells. Vitamin D reduced the phospho-NF-κB/p65 expression in the TNF-α-treated NP cells.

CONCLUSION

Vitamin D can attenuate TNF-α-induced NP cells apoptosis through interfering with the NF-κB pathway.