Changes In Mechanoreceptors Research Articles

Proprioception and Mechanoreceptors in Osteoarthritis: A Systematic Literature Review.

Osteoarthritis (OA) is one of the most common chronic diseases in the world. It is frequently accompanied by high levels of persistent pain, as well as substantial impairments in function and functional capacity. This review aims to systematically analyze the changes in proprioception and related mechanoreceptors in OA patients. Studies from September 2013 to September 2023 were identified by conducting searches on the PubMed, Web of Science, and Scopus electronic databases following the PRISMA statement. One reviewer independently assessed and screened the literature, extracted the data, and graded the studies. The body of evidence underwent an evaluation and grading process using the ROBINS-I tool, which was specifically designed to assess the risk of bias in non-randomized studies of interventions. Results were summarized using descriptive methods. A search through 37 studies yielded 14 clinical studies that were ultimately included. The primary focus of the studies was on the knee joint, particularly the posterior cruciate ligament (PCL). The studies found that PCL in OA patients had impaired proprioceptive accuracy, possibly due to changes in mechanoreceptors (Ruffini, Pacini, and Golgi Mazzoni corpuscles). This suggests that dysfunctional articular mechanoreceptors, especially in severe cases of OA, may contribute to reduced proprioception. Dynamic stabilometry also identified significant proprioceptive deficits in patients with knee articular cartilage lesions, underscoring the impact of such lesions on knee proprioception. Literature data have shown that proprioceptive accuracy may play an important role in OA, particularly in the knee PCL and cartilage. However, the role of proprioception and related mechanoreceptors needs to be further clarified. Future studies focusing on the relationship between proprioception, OA disease, and symptoms, considering age and gender differences, and exploring OA joints other than the knee should be conducted to improve clinical and surgical outcomes in cases where proprioception and mechanoreceptors are impaired in OA patients.

Changes in mechanoreceptors in rabbits' anterior cruciate ligaments with age.

At present, a few studies have been done on the changes in the distribution, morphology and quantity of mechanoreceptors in anterior cruciate ligament (ACL) with age. In this study, we observed the changes in mechanoreceptors of healthy rabbits' ACL with age. We found that rabbits' ACLs contained 5 kinds of mechanoreceptors including Ruffini corpuscles, Pacinian corpuscles, Golgitendon bodies, free nerve endings and atypical mechanoreceptors. In each ACL, free nerve endings were the most followed by Ruffini corpuscles, Pacinian corpuscles, Golgitendon bodies and atypical mechanoreceptors in the younger than one-old rabbits. Most of the mechanoreceptors were distributed in the synovium near the attachment points of ACL with the femur and tibia. The total quantity of mechanoreceptors were the most in the 3- and 6-month groups, but did not show a significant difference between the two group (P > 0.05). However, there were significant differences in the total quantity of mechanoreceptors between other groups (all P < 0.05). RT-PCR indicated that NEFM and S100B levels increased with age, and reached a peak in the 1-year group with significant differences as compared to other groups. NEFM and S100B levels were the second in 6-month and 2-year groups and the lowest in the 1-week group. We can conclude that in rabbits' ACLs, free nerve endings are the most common, followed by Ruffini corpuscles, Pacinian corpuscles and Golgitendon bodies. The total quantity of mechanoreceptors reaches a peak in 3 months, while NEFM and S100B reach a peak in 1year.

Changes of mechanoreceptors in different-state remnants of ruptured anterior cruciate ligament.

To observe the changes in the quantity and morphology of mechanoreceptors in different-state remnant stumps of ruptured anterior cruciate ligaments (ACLs). Specimens of completely ruptured ACL remnants were collected from 57 patients. The injury time from injury to surgery was recorded. According to the degree of pre-operative anterior displacement of knee joint, these patients were divided into two groups: group 1 (≤ 6mm) and group 2 (> 6mm). The morphology type of ligament remnant in each patient was identified. The correlations of mechanoreceptor number in the remnant stumps with the morphology of ligament stump, injured knee stability, and injury time were analyzed. Subsequently, based on ACL lesion type, patients were divided into four groups including groups A, B, C, and D, and then, the items above were compared among the four groups. Group 1 contained 20 specimens including threewith type B and 17 with type C. Group 2 contained 37 specimens including 20 with type A, 1 with type B, 2 with type C, and 14 with type D. The distributions of four-type remnant morphologies (X2 = 49.406, P = 0.000) and mechanoreceptors (X2 = 13.84, P = 0.002) were all significantly different between the two groups. The number of mechanoreceptors was positively correlated with the injured knee stability (r = 0.63,P = 0.018). The number of the mechanoreceptors was not obviously correlated with the injury time in group 1 (r = - 0.37,P = 0.136), while it was negatively correlated with the injury time in group 2 (r = - 0.51,P = 0.022). There was a significant difference in pre-operative anterior displacement of knee joint among groups A, B, C, and D (F= 85.59, P= 0.000), and the pre-operative anterior displacement of knee joint was less in groups B and C than in groups A and D. There was a significant difference in the distribution of typical and atypical mechanoreceptors among groups A, B, C, and D (X2= 68.16, P =0.032). The ruptured ACL remnants connecting the femur to tibia can still play a role in maintaining knee stability; thus, the mechanoreceptors can persist in these remnants for a long time.

Stratification of knee osteoarthritis: two major patient subgroups identified by genome wide expression analysis of articular cartilage

Introduction Osteoarthritis (OA) is a heterogeneous and complex disease. We have used a network biology approach based on genome-wide analysis of gene expression in OA knee cartilage to seek evidence for pathogenic mechanisms that may distinguish different patient subgroups. Methods Results from RNA-Sequencing (RNA-Seq) were collected from intact knee cartilage at total knee replacement from 44 patients with OA, from 16 additional patients with OA and 10 control patients with non-OA. Results were analysed to identify patient subsets and compare major active pathways. Results The RNA-Seq results showed 2692 differentially expressed genes between OA and non-OA. Analysis by unsupervised clustering identified two distinct OA groups: Group A with 24 patients (55%) and Group B with 18 patients (41%). A 10 gene subgroup classifier was validated by RT-qPCR in 16 further patients with OA. Pathway analysis showed increased protein expression in both groups. PhenomeExpress analysis revealed group differences in complement activation, innate immune responses and altered Wnt and TGFβ signalling, but no activation of inflammatory cytokine expression. Both groups showed suppressed circadian regulators and whereas matrix changes in Group A were chondrogenic, in Group B they were non-chondrogenic with changes in mechanoreceptors, calcium signalling, ion channels and in cytoskeletal organisers. The gene expression changes predicted 478 potential biomarkers for detection in synovial fluid to distinguish patients from the two groups. Conclusions Two subgroups of knee OA were identified by network analysis of RNA-Seq data with evidence for the presence of two major pathogenic pathways. This has potential importance as a new basis for the stratification of patients with OA for drug trials and for the development of new targeted treatments.

Changes of the mechanoreceptors in the different state remnant stump after ACL rupture

Objective To investigate the changes of mechanoreceptors in the different state remnant stumps after anterior cruciate ligament (ACL) rupture. Methods From March 2013 to December 2015, fifty-seven cases of complete ACL rupture were collected to record the time interval from injury to surgery.The patients were divided into two groups according to preoperative kneelax joint measurement results: ≤6 mm group (group 1) and>6 mm group (group 2). The morphology of each ligament stump in the two groups was recorded.After H&E staining and immunohistochemical labeling, the morphology, type, and quantity of the mechanoreceptors in the ligament stump were observed under an optical microscope.The relationship among the changes of the mechanoreceptors in the remnant stumps and the morphology of the ligament stump, the affected knee stability and the time from injury to surgery were analyzed. Results Twenty specimens were included in group 1.While 37 specimens were included in group 2.There was significant difference between the two groups in the distributions of the 4 types of the remnant stumps (P=0.000). There was significant difference between the two groups in the distributions of the 4 types of mechanoreceptors (P=0.002). The number of the mechanoreceptors was positively correlated with the affected knee stability (r=0.63, P=0.018). There was no significant correlation between the number of the mechanoreceptors and the time from injury to surgery in group1(r=-0.37, P=0.136), while the number of the mechanoreceptors was negatively correlated with the time from injury to surgery in group 2 (r=-0.51, P=0.022). Conclusion After ACL rupture, the ligament stump in some patients still connect the femur and the tibia in the joint cavity, and exert mechanical stability function, which can retain the mechanoreceptors in the tissue for a long time. Key words: Knee joint; Anterior cruciate ligament; Remnant; Mechanoreceptor

Stratification of knee osteoarthritis: two major patient subgroups identified by genome-wide expression analysis of articular cartilage

IntroductionOsteoarthritis (OA) is a heterogeneous and complex disease. We have used a network biology approach based on genome-wide analysis of gene expression in OA knee cartilage to seek evidence for...

Changes in the Mechanoreceptors of the Anterior Cruciate Ligament of Patients with Degenerative Arthritis

Purpose: To clarify the morphologic and quantitative changes of mechanoreceptors of the human ACL with degenerative arthritis. Materials and Methods: Eleven fresh specimens of anterior cruciate ligament (ACL) were obtained from patients with degenerative arthritis during TKA. As a control, two fresh specimens were taken from healthy men at the time of a traumatic above knee amputation. The whole ligaments were serially frozen and sectioned at a thickness of 40 . After immunohistochemical staining, the mechanoreceptors were observed under a light microscope. The ratios of sections showing mechanoreceptors were calculated. Statistical analyses were performed using the chi-square test. Results: In the two control specimens, nineteen mechanoreceptors were found, evenly distributed at the femoral and tibial ends. However, the average number of mechanoreceptors was 1.4 (total 15) in the arthritic ligaments (p

Aging and the perception of a racket's sweet spot

Young adults are able to perceive an implement's center of percussion (CP) or “sweet spot,” and to distinguish it from the implement's length, simply on the basis of wielding. Given the known changes in mechanoreceptors with aging, two experiments assessed these perceptual abilities in older adults (ranging in age from 62 to 89 years with an average of 69.2). They, too, distinguished length from the sweet spot simply on the basis of wielding, both for tennis rackets (Experiment 1) and for bats contrived from wooden rods with attached masses (Experiment 2). Results conformed to previous research on dynamic touch in showing that perceiving the extents of wielded objects is constrained by the moments of the objects' mass distributions. Moreover, so-called young–old plots were linear – older peoples' perceptions were predicted by younger peoples' perceptions – implicating a common underlying mechanism for the two age groups. Nonetheless, the perceived-to-actual functions were generally flatter for elderly participants. How aging might compromise the functioning of dynamic touch was discussed in terms of fractal organization and functional limitations.

Noise-induced tuning curve changes in mechanoreceptors.

Fibers from the tibial nerve of rat were isolated and spike activity recorded using monopolar hook electrodes. The receptive field (RF) of each recorded unit on the glabrous skin of the foot was mechanically stimulated with waveforms comprised of various frequency sine waves in addition to increasing levels of white noise. Single-unit responses were recorded for both rapidly adapting (RA) and slowly adapting (SA) units. Signal-to-noise ratio (SNR) of the output was quantified by the correlation coefficient (C1) between the input sine wave and the nerve responses. The addition of noise enhanced signal transmission in both RA and SA fibers. With increasing noise, the initially inverted "V"-shaped, zero-noise tuning curves for RA fibers broadened and eventually inverted. There was a large expansion of the frequencies that the RA receptor responded to with increasing noise input. On the other hand, the typical shape of the SA fiber tuning curves remained invariant, at all noise levels tested. C1 values continued to increase with larger noise input for higher frequencies, but did not do so at the lowest frequencies. For both RA and SA fibers the responses with added noise tended to be rate modulated at the low-frequency end, and followed nonlinear stochastic resonance (SR) properties at the higher frequencies. The changes in the tuning properties due to noise found here, as well as preliminary psychophysics data, imply that external noise is relevant for sensing small periodic signals in the environment. All current models of sensory perception assume that the tuning properties of receptors determined in the absence of noise are preserved during everyday tasks. Our results indicate that this is not true in a noisy environment.