Oral administration of undenatured native chicken type II collagen (UC-II) diminished deterioration of articular cartilage in a rat model of osteoarthritis (OA)

Temporal progression of subchondral bone alterations in OA models involving induction of compromised meniscus integrity in mice and rats: A scoping review

OBJECTIVE

To categorize the temporal progression of subchondral bone alterations induced by compromising meniscus integrity in mouse and rat models of knee osteoarthritis (OA).

METHOD

Scoping review of investigations reporting subchondral bone changes with appropriate negative controls in the different mouse and rat models of OA induced by compromising meniscus integrity.

RESULTS

The available literature provides appropriate temporal detail on subchondral changes in these models, covering the entire spectrum of OA with an emphasis on early and mid-term time points. Microstructural changes of the subarticular spongiosa are comprehensively described; those of the subchondral bone plate are not. In mouse models, global subchondral bone alterations are unidirectional, involving an advancing sclerosis of the trabecular structure over time. In rats, biphasic subchondral bone alterations begin with an osteopenic degeneration and loss of subchondral trabeculae, progressing to a late sclerosis of the entire subchondral bone. Rat models, independently from the applied technique, relatively faithfully mirror the early bone loss detected in larger animals, and the late subchondral bone sclerosis observed in human advanced OA.

CONCLUSION

Mice and rats allow us to study the microstructural consequences of compromising meniscus integrity at high temporal detail. Thickening of the subchondral bone plate, an early loss of thinner subarticular trabecular elements, followed by a subsequent sclerosis of the entire subchondral bone are all important and reliable hallmarks that occur in parallel with the advancing articular cartilage degeneration. Thoughtful decisions on the study design, laterality, selection of controls and volumes of interest are crucial to obtain meaningful data.

Food-derived bioactive peptides potentiating therapeutic intervention in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects the joints of the human body and is projected to have a prevalence age-standardized rate of 1.5 million new cases worldwide by 2030. Several conventional and non-conventional preventive and therapeutic interventions have been suggested but they have their side effects including nausea, abdominal pain, liver damage, ulcers, heightened blood pressure, coagulation, and bleeding. Interestingly, several food-derived peptides (FDPs) from both plant and animal sources are increasingly gaining a reputation for their potential in the management or therapy of RA with little or no side effects. In this review, the concept of inflammation, its major types (acute and chronic), and RA identified as a chronic type were discussed based on its pathogenesis and pathophysiology. The conventional treatment options for RA were briefly outlined as the backdrop of introducing the FDPs that potentiate therapeutic effects in the management of RA.

High gastrointestinal digestive stability endows chondroitin sulfate-soluble undenatured type II collagen complex with high activity: Improvement of osteoarthritis in rats

Previously, we prepared a chondroitin sulfate-soluble undenatured type II collagen complex (CS-SC II) with low salt content. This paper further explored the differences between CS-SC II and SC II in terms of gastrointestinal digestive characteristics and osteoarthritis (OA) improvement. In vitro and in vivo experiments showed that the gastric digestive stability of CS-SC II was high under both pH 2.0 and pH 3.0, the α1 chain and triple helix structure of type II collagen retained >60 %. However, SC II had high gastric digestive stability only under pH 3.0. Furthermore, intestinal digestion had little effect on α1 chains of CS-SC II and SC II, and distribution experiments showed that they might exert their biological activities in the intestine. CS-SC II had obvious improvement in OA rats at 1.0 mg/kg/d, that is, the joint swelling was significantly reduced and the weight-bearing ratio of the right hind limb was increased to 49 %, which was close to that of 4.0 mg/kg/d SC II. The wear of articular cartilage, Mankin and OARSI scores of rats in CS-SC II group were significantly reduced. The effects of low-dose CS-SC II on the proportion of regulatory T cells (Treg), mRNA expression of OA key biomarkers (Il6, Ccl7, MMP-3 and MMP13) and signaling pathway genes (NF-κB, AKT or AMPKα) were comparable to those of high-dose SC II. These results showed that CS-SC II might have greater potential to improve OA at a lower dose than SC II due to its high gastrointestinal digestive stability at a wide range of pH conditions.

Evaluation of the Effects of an Undenatured Collagen Type-2-Based Nutraceutical (ARTHROSHINE® HA²) on Recovery Time after TPLO in Dogs: A Prospective, Randomized Study with Objective Gait Analysis as the Primary Outcome Measure

This randomized, prospective clinical trial investigates the impact of a novel undenatured collagen type 2 (T2NDC)-based nutraceutical, ARTHROSHINE® HA² (AS), on postoperative rehabilitation following Tibial Plateau Leveling Osteotomy (TPLO) in 50 dogs with unilateral cranial cruciate ligament rupture (CCLR). The patients were randomly allocated to either group A, receiving AS once daily for 24 weeks post-TPLO surgery, or group B, without any supplementation. Frequency matching was applied to enhance group comparability. Assessment of outcomes included computerized gait analysis and a validated owner questionnaire. AS supplementation was well received, without any reported side effect. Consistently, patients in group A exhibited significantly higher peak vertical force values during all follow-up assessments. By the 12-week mark, gait analysis indicated a return to a physiological gait pattern in group A, while group B achieved this normalization only by the 24-week point. The administration of AS post-TPLO surgery demonstrates promise in enhancing limb function, leading to faster restoration of a physiological gait pattern. The inclusion of AS, a T2NDC-based nutraceutical, in the post-TPLO rehabilitation protocol may contribute to improved limb function and an expedited recovery, potentially facilitating a quicker return to normalcy. It is noteworthy that subjective owner perceptions did not differ between the two groups.

Current evidence for non-pharmaceutical, non-surgical treatments of canine osteoarthritis

Osteoarthritis is a progressive degenerative disease process that affects a significant proportion of the canine population, impacting these animals' quality of life. Currently, there is no cure and treatment consists of managing the clinical signs of pain and reduced mobility. There are many treatments for canine osteoarthritis and in this review we discuss the evidence base behind non-pharmaceutical, non-surgical treatments of this disease. These treatments include weight management, nutraceuticals, acupuncture, physiotherapies such as therapeutic exercise, hydrotherapy as well as other therapeutic modalities including photobiomodulation therapy, electromagnetic field therapy and others.

Differences between soluble and insoluble undenatured type II collagen in improving osteoarthritis in rats and their potential mechanisms

Our previous research showed that soluble (SC II) and insoluble (IC II) undenatured type II collagen had significant differences during gastrointestinal digestion in vitro, and SC II exposed more type II collagen with triple helix structure. However, the differences in their in vivo digestive characteristics, improvement on osteoarthritis (OA), and possible mechanisms have not been elucidated. The aim of this study was to explore these issues. After oral administration of SC II and IC II, the joint swelling of OA rats significantly reduced, and the weight bearing ratio of right hind limb significantly increased, especially in SC II group (raised to 48%). The Mankin and OARSI scores decreased by 35% and 48% in SC II group, respectively. SC II and IC II increased the mRNA expression of anti-inflammatory factors and the proportion of regulatory T cells (Treg). Importantly, type II collagen released by IC II during in vivo gastrointestinal digestion was far less than SC II, which explained the higher ability of SC II to induce immune tolerance in small intestine than IC II. Bioinformatics analysis showed that the differential genes between model and control were significantly enriched in PI3K/AKT, PPAR and AMPK signalling pathways, and 24 hub genes were analyzed. SC II significantly down-regulated the mRNA expression of Il6, Ccl7, NF-κB, AKT and up-regulated the mRNA expression of Scd1. These results showed that SC II was superior to IC II in improving OA by inducing immune tolerance and could regulate key biomarkers and signalling pathways in OA rats.

Undenatured type II collagen and its role in improving osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease, affecting 32.5 million US adults or 242 million people worldwide. There is no cure for OA. Many animal and clinical trials showed that oral administration of undenatured type II collagen could significantly reduce the incidence of OA or alleviate the symptoms of articular cartilage. Type II collagen is an important component of cartilage matrix. This article reviewed research progress of undenatured type II collagen including its methods of extraction and preparation, structure and characterization, solubility, thermal stability, gastrointestinal digestive stability, its role in improving OA, and the mechanism of its action in improving OA. Type II collagen has been extensively explored for its potential in improving arthritis. Methods of extraction of type II collagen are inefficient and tedious. The method of limited enzymatic hydrolysis is mainly used to prepare soluble undenatured type II collagen (SC II). The solubility, thermal and gastrointestinal digestive stability of SC II are affected by the sources of raw material, pH, salt ions, and temperature. Oral administration of undenatured type II collagen improves OA, whereas its activity is affected by the sources, degree of denaturalization, intervention methods and doses. However, the influence of the structure of undenatured type II collagen on its activity and the mechanism are unclear. The findings in this review support that undenatured type II collagen can be used in the intervention or auxiliary intervention of patients with OA.

Oral Administration of Protease-Soluble Chicken Type II Collagen Ameliorates Anterior Cruciate Ligament Transection-Induced Osteoarthritis in Rats

This study investigated whether oral supplementation with protease-soluble chicken type II collagen (PSCC-II) mitigates the progression of anterior cruciate ligament transection (ACLT)-induced osteoarthritis (OA) in rats. Eight-week-old male Wistar rats were randomly assigned to the following groups: control, sham, ACLT, group A (ACLT + pepsin-soluble collagen type II collagen (C-II) with type I collagen), group B (ACLT + Amano M-soluble C-II with type I collagen), group C (ACLT + high-dose Amano M-soluble C-II with type I collagen), and group D (ACLT + unproteolyzed C-II). Various methods were employed to analyze the knee joint: nociceptive tests, microcomputed tomography, histopathology, and immunohistochemistry. Rats treated with any form of C-II had significant reductions in pain sensitivity and cartilage degradation. Groups that received PSCC-II treatment effectively mitigated the ACLT-induced effects of OA concerning cancellous bone volume, trabecular number, and trabecular separation compared with the ACLT alone group. Furthermore, PSCC-II and unproteolyzed C-II suppressed ACLT-induced effects, such as the downregulation of C-II and upregulation of matrix metalloproteinase-13, tumor necrosis factor-α, and interleukin-1β. These results indicate that PSCC-II treatment retains the protective effects of traditional undenatured C-II and provide superior benefits for OA management. These benefits encompass pain relief, anti-inflammatory effects, and the protection of cartilage and cancellous bone.

The effect of oral administration of undenatured type II collagen on monosodium iodoacetate-induced osteoarthritis in young and old rats

We investigated whether different doses of undenatured type II collagen (undenatured collagen, UC-II) help improve monosodium iodoacetate (MIA)-induced (osteoarthritis) OA in young and old rats. A total of 70 rats were divided into five groups: (1) control; (2) MIA (a single intra-articular injection of MIA); (3)-(5) MIA+ Undenatured Collagen with various oral doses (0.66, 1.33, and 2 mg/kg). The results showed that all doses of undenatured collagen in both age groups reduced knee diameter, while the two higher doses (1.33 mg/kg and 2 mg/kg) reduced the Mankin score and increased most gait measurements as early as day 14 compared to the MIA rats. However, the 2 mg/kg dose showed the best efficacy in improving Mankin score and gait measurements by 28 days post-OA induction. In young but not old rats, all doses of undenatured collagen reduced the Kellgren-Lawrence score compared to the MIA group. Undenatured collagen reduced the levels of most inflammatory and cartilage breakdown markers in serum and knee joint cartilage in both age groups. In conclusion, this data suggests that while all doses of undenatured collagen supplementation may ameliorate MIA-induced OA symptoms, the higher doses showed faster improvement in gait measurements and were more efficacious for overall joint health in rats.

Earlier and More Severe Cartilage Degeneration Occurs After Meniscal Tears in Juvenile Rabbits Compared with Adults

OBJECTIVE

To compare the severity of cartilage degeneration after meniscal tears between juvenile and adult rabbits.

DESIGN

This study included 20 juvenile rabbits (2 weeks after birth) and 20 adult rabbits (6 months after birth). Meniscal tears were prepared in the anterior horn of medial menisci of right knees. Rabbits were sacrificed at 1, 3, 6, and 12 weeks postoperatively. Cartilage degenerations in the medial femoral condyle and medial tibial plateau were evaluated macroscopically and histologically. The semiquantitative assessment of cartilage degeneration was graded by macroscopic Outerbridge scoring system and histological Osteoarthritis Research Society International (OARSI) scoring system.

RESULTS

In juvenile rabbits, the morphologically intact cartilage and normal extracellular matrix architecture were observed at the first week postoperatively. Mild uneven cartilage surface and toluidine blue depletion in the medial femoral condyle were observed on histological assessment at 3 weeks postoperatively. The worsened cartilage deterioration demonstrating chondral fibrillation, prominent cell death, and glycosaminoglycan (GAG) release was observed at 6 and 12 weeks postoperatively. In adult rabbits, only mild cartilage degeneration was observed in the medial femoral condyle at 12 weeks postoperatively. The outcomes of Outerbridge and OARSI scores were consistent with the aforementioned findings in juvenile and adult rabbits.

CONCLUSIONS

Our study validated that earlier and more severe cartilage degenerations were observed in juvenile rabbits after meniscal tears compared with adult rabbits. Moreover, the post-tear cartilage degeneration demonstrated regional specificity corresponded to the tear position. However, caution is warranted when extrapolating results of animal models to humans.

1H-NMR metabolomic profile of healthy and osteoarthritic canine synovial fluid before and after UC-II supplementation

The aim of the study was to compare the metabolomic synovial fluid (SF) profile of dogs affected by spontaneous osteoarthritis (OA) and supplemented with undenatured type II collagen (UC-II), with that of healthy control dogs. Client-owned dogs were enrolled in the study and randomized in two different groups, based on the presence/absence of OA (OA group and OA-free group). All dogs were clinically evaluated and underwent SF sampling for ¹H-Nuclear Magnetic Resonance spectroscopy (¹H-NMR) analysis at time of presentation. All dogs included in OA group were supplemented with UC-II orally administered for 30 days. After this period, they were reassessed (OA-T30). The differences in the ¹H-NMR metabolic SFs profiles between groups (OA-free, OA-T0 and OA-T30) were studied. The multivariate statistical analysis performed on SFs under different conditions (OA-T0 vs OA-T30 SFs; OA-T0 vs OA-free SFs and OA-T30 vs OA-free SFs) gave models with excellent goodness of fit and predictive parameters, revealed by a marked separation between groups. β-Hydroxybutyrate was identified as a characteristic compound of osteoarthritic joints, showing the important role of fat metabolism during OA. The absence of β-hydroxybutyrate after UC-II supplementation suggests the supplement's effectiveness in rebalancing the metabolism inside the joint. The unexpectedly high level of lactate in the OA-free group suggests that lactate could not be considered a good marker for OA. These results prove that ¹H-NMR-based metabolomic analysis is a valid tool to study and monitor OA and that UC-II improves clinical symptoms and the SF metabolic profile in OA dogs.

Evaluation of clinical efficacy of undenatured type II collagen supplementation compared to cimicoxib and their association in dogs affected by natural occurring osteoarthritis

The aim of the study was to evaluate the clinical efficacy of 30 days treatment of undenatured type II collagen(UC-II®), compared to cimicoxib and to their combination, in osteoarthritic dogs. Client-owned dogs were enrolled in a clinical, randomized, controlled and prospective study. Posture, lameness, pain, range of motion and x-ray of affected joint(s) were evaluated and scored based on severity (CLINICAL score). The Liverpool Osteoarthritis in Dogs survey was used to score the owner evaluation of dog's mobility (LOAD score and MOBILITY score). Osteoarthritis (OA) stage was defined through the Canine Osteoarthritis Staging tool (COAST). After diagnosis (T0), all patients were randomly assigned to different treatment groups: C group = cimicoxib 2 mg/kg/day orally OS, F group = UC-II® 1 tablet per day OS; C + F group = cimicoxib-UC-II® at the same previous dosages; CTR group = dogs who didn't received any treatment. All treatments were administered for 30 days. Seventy-six dogs completed the study. LOAD score was recorded significant lower after treatment for each group, with a reduction in percentage of 29.5% for C, 31.4% for F, 21.1% for C + F. LOAD score was lower in C(P = 0.04), F(P = 0.001) and C + F(P = 0.009) group at T30 than CTR group. MOBILITY and CLINICAL scores were significantly lower in all groups at T30, when compared to T0. MOBILITY score was lower than CTR in C(P = 0.02) and F(P = 0.01); CLINICAL score was lower in C + F(P = 0.016). The present findings prove that the treatment with UC-II®, cimicoxib and their combination provide significant reduction in clinical signs associated with OA.

Comparison between exercise therapy and non-hydrolyzed collagen (UC-II) in functionality and quality of life in women with knee osteoarthritis : A randomized controlled clinical trial

BACKGROUND

Knee osteoarthritis (OA) is characterized by a progressive degeneration of cartilage and menisci, leading to pain and locomotor disability. Here, we aimed to assess the effect of an exercise protocol and the oral use of non-hydrolyzed collagen (UC-II) on the functionality and quality of life of women with knee OA.

MATERIAL AND METHODS

Individuals were divided into three groups (CG [control group]; MG [medication group]; EG [exercise group]). In the CG there was no intervention, while MG received an oral dose (1 capsule/day) of UC-II and the EG held 12 sessions of an exercise protocol.

RESULTS

In the functionality tests (6-min walk test, 6MWT and timed up and go test [TUG]) the EG (p < 0.001/p = 0.020) and MG (p = 0.010/p = 0.010) revealed a significant improvement when compared to the CG. In the analysis of quality of life by WOMAC, a significant improvement was found only in the EG (p = 0.030) when compared to the CG; the same happened in the stiffness domain (EG, p = 0.010), despite in the pain domain, both the EG (p < 0.001) and the MG (p = 0.060) were better than the CG.

CONCLUSION

Data obtained here reveal that an exercise protocol and UC-II have similar effects for functionality, despite exercise being superior in promoting the quality of life score.

Therapeutic Effect of Nile Tilapia Type II Collagen on Rigidity in CD8+ Cells by Alleviating Inflammation and Rheumatoid Arthritis in Rats by Oral Tolerance

Fibrillins are microfibril-associated macro glycoproteins found in connective tissues and structurally related to latent TGF-β-binding proteins (LTBPs). The special cellular immunity and blocking glycoprotein receptors IIb and IIIa of fibrillins are emerging topics in recent years. In this study, Nile Tilapia type IIcollagen (NTCII) was extracted and purified from the skull cartilages by a pepsin-soluble method. Amino acid analysis indicated that NTCII consisted of 315/1000 glycine residues, 72/1000 hydroxyproline residues and 108/1000 proline residues. SDS-PAGE analysis showed that NTCII was composed of three identical 130 kDa α-chains. The results of glycoprotein/carbohydrate assay indicated that the total polysaccharide content of NTCII was 5.6–19.0%. The IR spectrum of NTCII displayed five characteristic peaks of amide I, II, III, A, B. NTCII at 10–100 μg/mL concentration downregulated the content of cytokines in the presence or absence of LPS, especially the secretion of cytokines IL-6, IL-1β and TNF-α. Interestingly, NTCII promoted the secretion of Fas/Apo-1 compared to the control group and 25 μg/mL of NTCII resulted in a higher Fas/Apo-1 secretion level in CD8⁺ T cells. FITC-TCII fluorescence images confirmed that NTCII could bind to the membrane surface of CD8⁺ T cells, leading to the induction of rigidity. NTCII could bind to the membrane surface of CD8⁺ T cells that leads to the induction of rigidity, as evidenced by the FITC-NTCII fluorescence images. The qRT-PCR gene expression analysis of caspase-8 collected with Fas/Apo-1 was upregulated significantly in the 1 and 50 μg/mL NTCII-treated groups compared with the control group. Overall, the results conclude that the rigidity did not lead to an increase in inflammatory factors in CD8⁺ T cells treated with NTCII. The oral administration of NTCII 3 mg/kg dosage caused more prominent repair of damaged ankle cartilage than the 1 mg/kg dosage in Freund’s adjuvant-induced model of arthritis in rats. Therefore, this study disclosed the immunological and anti-arthritic effect of fibrillar collagen, which could be a potential biomaterial for practical applications with lower toxicity.

Effects of type II collagen hydrolysates on osteoarthritis through the NF-κB, Wnt/β-catenin and MAPK pathways

Osteoarthritis (OA), a degenerative disease, has attracted extensive attention all over the world. In this study, a rat model involving medial meniscus resection (MMx) and anterior to medial collateral ligament (ACL) operation was successfully established to study the effects of bovine cartilage hydrolysates rich in type II collagen peptides (BIIP) on cartilage protection. The results of histological analysis indicated that oral administration of BIIP at doses of 200 and 500 mg kg^-1 d^-1 ameliorated cartilage degeneration. Moreover, the potential targets of BIIP affecting OA in vivo were studied by proteomics, and the effects of BIIP on OA through signaling pathways, such as NF-κB, Wnt/β-catenin and MAPK, were further explored at mRNA and protein levels. BIIP downregulated the expression of IL-6, RUNX2, NF-κB p65, HIF-2α, β-catenin and p-JNK, which may be the main factor leading to the prevention of OA. These results suggest that BIIP can be used as a novel potential substance of functional foods to exert chondroprotective action.

[Longitudinal In Vivo Evaluation of Knee Osteoarthritis Model Using 7 T-MRI and Micro-CT]

PURPOSE

This study aims to investigate inflammatory changes and osteophyte formation in a rat osteoarthritis (OA) model longitudinally by using 7 T-magnetic resonance imaging (MRI) and micro-computed tomography (CT).

METHOD

This OA model is induced surgically by removing the medial collateral ligament and medial meniscus of the right knee joint. Using 7 T-MRI, we compared the relative signal value of the medial collateral site and the area (mm²) of the upper end of the tibia at the right knee joint to those of the left knee joint on T₂WI. In addition, we compared statistically the coefficient of variance (CV) of signal intensity on the subchondral bone, the area (mm²), the major axis (mm) and the minor axis (mm) of the upper end of the tibia by the use of micro-CT images.

RESULTS

In MRI experiment, the relative signal value was significantly higher at 2, 6, and 10 weeks postoperatively in the medial part of right knee joint than that in the left one. In micro-CT experiment, CV was significantly higher from 6 weeks postoperatively in the subchondral bone of surgical side. Rough and irregular surface at the medial tibia was also observed by 3D images.

CONCLUSION

Using 7 T-MRI and micro-CT, we're able to observe the knee osteoarthritis model rat longitudinally.

A White Paper on Collagen Hydrolyzates and Ultrahydrolyzates: Potential Supplements to Support Joint Health in Osteoarthritis?

PURPOSE OF REVIEW

Osteoarthritis (OA) is the most common forms of arthritis in the general population, accounting for more pain and functional disability than any other musculoskeletal disease. There are currently no approved disease modifying drugs for OA. In the absence of effective pharmacotherapy, many patients with OA turn to nutritional supplements and nutraceuticals, including collagen derivatives. Collagen hydrolyzates and ultrahydrolyzates are terms used to describe collagens that have been broken down into small peptides and amino acids in the presence of collagenases and high pressure.

RECENT FINDINGS

This article reviews the relevant literature and serves as a White Paper on collagen hydrolyzates and ultrahydrolyzates as emerging supplements often advertised to support joint health in OA. Collagen hydrolyzates have demonstrated some evidence of efficacy in a handful of small scale clinical trials, but their ability to treat and reverse advanced joint disease remains highly speculative, as is the case for other nutritional supplements. The aim of this White Paper is to stimulate research and development of collagen-based supplements for patients with OA and other musculoskeletal diseases at academic and industrial levels. This White Paper does not make any treatment recommendations for OA patients in the clinical context, but simply aims to highlight opportunities for scientific innovation and interdisciplinary collaboration, which are crucial for the development of novel products and nutritional interventions based on the best available and published evidence.

Interleukin‑Iβ promotes cartilage degeneration by regulating forkhead box protein O4 and type Ⅱ collagen

Osteoarthritis (OA) is one of the most prevalent pain-inducing and disabling diseases globally. Aging is a primary contributing factor to the progression of OA. Forkhead box protein O4 (FOXO4) is known to be involved in the cell cycle and apoptosis regulation. The aim of the present study was to investigate the association between FOXO4 expression and chondrocyte degeneration in rats. Chondrocytes were assigned to the control (4-week-old rats), natural degeneration (16-week-old rats) or induced degeneration (IL-1β-treated chondrocytes from 4-week-old rats) groups. Immunocytochemical analysis with β-galactosidase staining revealed a greater number of stained cells present in the natural and induced degeneration groups than in the control group. PCR analysis indicated lower mRNA expression levels of collagen type II α1 chain (Col2α) and higher levels of FOXO4, and western blotting revealed reduced Col2α protein expression levels and significantly elevated FOXO4 levels in the natural and induced degeneration groups, compared with those in the control group. The results of the present study revealed that FOXO4 expression was altered in the natural and induced degeneration groups, and further research and exploration are needed to clarify the underlying mechanism.

Curcumenol mitigates chondrocyte inflammation by inhibiting the NF‑κB and MAPK pathways, and ameliorates DMM‑induced OA in mice

At present, an increasing number of individuals are affected by osteoarthritis (OA), resulting in a heavy socioeconomic burden. OA in knee joints is caused by the release of inflammatory cytokines and subsequent biomechanical and structural deterioration. To determine its anti‑inflammatory function, the current study investigated the use of the plant‑derived medicine, curcumenol, in OA treatment. Curcumenol was not cytotoxic to ATDC5 chondrocytes and primary chondrocytes, as determined using a cell viability test. When these cells were treated with TNF‑α and IL‑1β to induce inflammation, curcumenol treatment inhibited the progression of inflammation by inactivating the NF‑κB and MAPK signaling pathways, as well as decreasing the expression levels of MMP3 (as indicated by reverse transcription‑quantitative PCR and western blotting). Moreover, to analyze metabolic and catabolic status in high‑density and pellet culture, catalytic changes and the degradation of the extracellular matrix induced by TNF‑α and IL‑1β, were evaluated by alcian blue staining. These catalytic deteriorations were ameliorated by curcumenol. Using curcumenol in disease management, the mechanical and metabolic disruption of cartilage caused in the destabilization of medial meniscus (DMM) model was prevented in vivo. Thus, curcumenol mitigated inflammation in ATDC5 chondrocytes and primary mice chondrocytes, and also ameliorated OA in a DMM‑induced mouse model.

Undenatured Type II Collagen Relieves Bone Impairment through Improving Inflammation and Oxidative Stress in Ageing db/db Mice

Ageing-related bone impairment due to exposure to hyperglycemic environment is scarcely researched. The aim was to confirm the improvement effects of undenatured type II collagen (UC II) on bone impairment in ageing db/db mice, and the ageing model was established by normal feeding for 48-week-old. Then, the ageing db/db mice were randomly assigned to UC II intervention, the ageing model, and the chondroitin sulfate + glucosamine hydrochloride control groups. After 12 weeks of treatment, femoral microarchitecture and biomechanical parameters were observed, biomarkers including bone metabolism, inflammatory cytokines, and oxidative stress were measured, and the gastrocnemius function and expressions of interleukin (IL) 1β, receptor activator of nuclear factor (NF)-κB ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) were analyzed. The results showed that the mice in the UC II intervention group showed significantly superior bone and gastrocnemius properties than those in the ageing model group, including bone mineral density (287.65 ± 72.77 vs. 186.97 ± 32.2 mg/cm³), gastrocnemius index (0.46 ± 0.07 vs. 0.18 ± 0.01%), muscle fiber diameter (0.0415 ± 0.005 vs. 0.0330 ± 0.002 mm), and cross-sectional area (0.0011 ± 0.00007 vs. 0.00038 ± 0.00004 mm²). The UC II intervention elevated bone mineralization and formation and decreased bone resorption, inflammatory cytokines, and the oxidative stress. In addition, lower protein expression of IL-1β, RANKL, and TRAP in the UC II intervention group was observed. These findings suggested that UC II improved bones impaired by T2DM during ageing, and the likely mechanism was partly due to inhibition of inflammation and oxidative stress.

Niacinamide and undenatured type II collagen modulates the inflammatory response in rats with monoiodoacetate-induced osteoarthritis

The current work aimed to examine the properties of oral supplementation of niacinamide and undenatured type II collagen (UCII) on the inflammation and joint pain behavior of rats with osteoarthritis (OA). Forty-nine Wistar rats were allocated into seven groups; control (no MIA), MIA as a non-supplemental group with monosodium iodoacetate (MIA)-induced knee osteoarthritis, MIA + undenatured type II collagen (UCII) at 4 mg/kg BW, MIA + Niacinamide at 40 mg/kg BW (NA40), MIA + Niacinamide at 200 mg/kg BW (NA200), MIA + UCII + NA40 and MIA + UCII + NA200. Serum IL-1β, IL-6, TNF-α, COMP, and CRP increased in rats with OA and decreased in UCII and NA groups (p < 0.05). Rats with osteoarthritis had greater serum MDA and knee joint MMP-3, NF-κB, and TGβ protein levels and decreased in treated groups with UCII and NA (p < 0.05). The rats with OA also bore elevated joint diameters with joint pain behavior measured as decreased the stride lengths, the paw areas, and the paw widths, and increased the Kellgren-Lawrence and the Mankin scores (p < 0.05) and decreased in UCII treated groups. These results suggest the combinations with the UCII + NA supplementation as being most effective and reduce the inflammation responses for most OA symptoms in rats.

Effects of Exercise Combined with Undenatured Type II Collagen on Endurance Capacity, Antioxidant Status, Muscle Lipogenic Genes and E3 Ubiquitin Ligases in Rats

The current study aimed to investigate the effect of exercise combined with undenatured type II collagen (UCII) administration on endurance capacity, lipid metabolism, inflammation, and antioxidant status in rats. Twenty-one male Wistar albino rats were divided into three groups as follows: (1) Sedentary control, (2) Exercise (E), (3) Exercise + UCII (4 mg/kg BW/day; E + UCII). The findings showed that the exhaustive running time in the UCII group was significantly prolonged compared to that of the non-supplemented group (p < 0.001). When compared to the control group, total serum cholesterol (TC, p < 0.05) and triglyceride (TG, p < 0.05) levels decreased, while creatinine kinase (CK) levels increased in the E group (p < 0.001). Serum creatinine kinase levels were reduced in the E + UCII group compared to the E group (p < 0.01). Serum lactate, myoglobin (p < 0.01), and osteocalcin levels (p < 0.01) increased significantly in exercised rats compared to sedentary control rats, while serum lactate (p < 0.01) and myoglobin (p < 0.0001) levels decreased in the E + UCII group compared to control. Additionally, UCII supplementation caused significant increases in antioxidant enzyme activities [SOD (p < 0.01) and GSH-Px (p < 0.05)] and decreases in malondialdehyde (MDA) and tumor necrosis factor (TNF-α) levels (p < 0.001). Muscle lipogenic protein (SREBP-1c, ACLY, LXR, and FAS) levels were lower in the E + UCII group than in other groups. In addition, UCII supplementation decreased muscle MAFbx, MuRF-1, myostatin and increased MyoD levels in exercised rats. Moreover, the E + UCII group had lower muscle inflammatory markers [TNF-α (p < 0.0001) and IL-1β (p < 0.01)] than the control group. These results suggest exercise combined with UCII (4 mg/kg BW/day) modulates lipid, muscle, and antioxidant status in rats.

Undenatured Type II Collagen Ameliorates Inflammatory Responses and Articular Cartilage Damage in the Rat Model of Osteoarthritis

Osteoarthritis (OA) is an age-related joint disease that includes gradual disruption of the articular cartilage and the resulting pain. The present study was designed to test the effects of undenatured type II collagen (UC-II®) on joint inflammation in the monoiodoacetate (MIA) OA model. We also investigated possible mechanisms underlying these effects. Female Wistar rats were divided into three groups: (i) Control; (ii) MIA-induced rats treated with vehicle; (iii) MIA-induced rats treated with UC-II (4 mg/kg BW). OA was induced in rats by intra-articular injection of MIA (1 mg) after seven days of UC-II treatment. UC-II reduced MIA-induced Kellgren-Lawrence scoring (53.3%, P < 0.05). The serum levels of inflammatory cytokines [IL-1β (7.8%), IL-6 (18.0%), TNF-α (25.9%), COMP (16.4%), CRP (32.4%)] were reduced in UC-II supplemented group (P < 0.0001). In the articular cartilage, UC-II inhibited the production of PGE2 (19.6%) and the expression of IL-1β, IL-6, TNF-a, COX-2, MCP-1, NF-κB, MMP-3, RANKL (P < 0.001). The COL-1 and OPG levels were increased, and MDA decreased in UC-II supplemented rats (P < 0.001). UC-II could be useful to alleviate joint inflammation and pain in OA joints by reducing the expression of inflammatory mediators.

The gut microbiome-joint connection: implications in osteoarthritis

Supplemental Digital Content is available in the text

Osteoarthritis is a debilitating disease leading to joint degeneration, inflammation, pain, and disability. Despite efforts to develop a disease modifying treatment, the only accepted and available clinical approaches involve palliation. Although many factors contribute to the development of osteoarthritis, the gut microbiome has recently emerged as an important pathogenic factor in osteoarthritis initiation and progression. This review examines the literature to date regarding the link between the gut microbiome and osteoarthritis.

Protein solubility, secondary structure and microstructure changes in two types of undenatured type II collagen under different gastrointestinal digestion conditions

Sodium dodecyl sulfonate polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism spectroscopy (CD), transmission electron microscope (TEM) and atomic force microscope (AFM) were used to analyze the structural properties and gastrointestinal digestive characteristics of natural insoluble undenatured type II collagen (IC II) and pepsin soluble undenatured type II collagen (SC II). Results showed that, after gastric digestion, especially under low pH conditions, some thick and short collagen fibers were dissolved from IC II, which was accompanied by the release of soluble protein with triple helix structure. As to SC II, when gastric digestion was performed under higher pH conditions, collagen fibers were mildly thinned and curved, and the triple helix structure was slightly destroyed. However, those changes hardly occurred during the intestinal digestion. Moreover, the undenatured type II collagen existing in SC II digestive supernatant was 1.2-12.4 times higher than that of IC II depending on the pH conditions. These results suggested that, it is more likely for SC II to exert its activity of relieving arthritis, and it should be taken when the pH of gastric environment is high.

Role of Collagen Derivatives in Osteoarthritis and Cartilage Repair: A Systematic Scoping Review With Evidence Mapping

Introduction

There is currently no disease-modifying drug for osteoarthritis (OA), and some safety concerns have been identified about the leading traditional drugs. Therefore, research efforts have focused on alternatives such as supplementation with collagen derivatives. The objective of this scoping review is to examine the extent, range, and nature of research, and to summarize and disseminate research findings on the effects of collagen derivatives in OA and cartilage repair. The purpose is to identify gaps in the current body of evidence in order to further help progress research in this setting.

Methods

The databases Medline, Scopus, CENTRAL, TOXLINE, and CDSR were comprehensively searched from inception to search date. After studies selection against eligibility criteria, following recommended methods, data were charted from the retrieved articles and these were subsequently synthesized. Numerical and graphical descriptive statistical methods were used to show trends in publications and geographical distribution of studies.

Results

The systematic literature search identified a total of 10,834 records. Forty-one published studies were ultimately included in the review, 16 of which were preclinical studies and 25 were clinical studies (including four systematic reviews/meta-analyses). Collagen hydrolysate (CH) and undenatured collagen (UC) were the two types of collagen derivatives studied, with a total of 28 individual studies on CH and nine on UC. More than a third of studies originated from Asia, and most of them have been published after 2008. Oral forms of collagen derivatives were mainly studied; three in vivo preclinical studies and three clinical trials investigated intra-articularly injected CH. In most of the clinical trials, treatment durations varied between 3 and 6 months, with the shortest being 1.4 months and the longest 11 months. All in vivo preclinical studies and clinical trials, regardless of their quality, concluded on beneficial effects of collagen derivatives in OA and cartilage repair, whether used as nutritional supplement or delivered intra-articularly, and whatever the manufacturers of the products, the doses and the outcomes considered in each study.

Conclusions

Although current evidence shows some potential for the use of CH and UC as an option for management of patients with OA, there is still room for progress in terms of laboratory and clinical research before any definitive conclusion can be made. Harmonization of outcomes in preclinical studies and longer randomized placebo-controlled trials in larger populations with the use of recommended and validated endpoints are warranted before collagen derivatives can be recommended by large scientific societies.

Electronic Supplementary Material

The online version of this article (10.1007/s40744-020-00240-5) contains supplementary material, which is available to authorized users.

Structural characterization and in vitro immunogenicity evaluation of amphibian-derived collagen type II from the cartilage of Chinese Giant Salamander (Andrias davidianus)

Collagen type II (CT-II) has unique biological activities and functions, yet the knowledge on amphibian-derived CT-II is rare. Herein, acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were successfully isolated and characterized from the cartilage of Chinese Giant Salamander (CGS). The in vitro immunogenicity of collagen was then evaluated and compared with that of the standard bovine CT-II (SCT-II) by T-lymphocyte cell proliferation activity. Results demonstrated that ASC and PSC were predominantly CT-II along with minor collagen type I and maintained intact triple-helical structure of nature collagen. Compared with SCT-II, higher glycine content (337.80 and 339.93 residues/1000 residues) and lower degree of proline hydroxylation (51.81% and 52.52%) were observed in ASC and PSC. Additionally, PSC showed comparable T _d (63 °C) and higher T _m (109 °C) than SCT-II (64 °C and 103 °C, respectively), indicating its high thermal and structural stability. SEM revealed that the lyophilized ASC and PSC had interconnected porous network structures of collagen-based materials. Moreover, different from SCT-II, both ASC and PSC presented no immunogenicity because they did not cause obvious proliferation of murine T-lymphocyte regardless of the induced concentration of collagen increased from 8 to 417 μg/mL. These data suggested that the amphibian-derived CGS cartilage collagens avoid the immunogenic risk of terrestrial animal collagen, and show high thermal stability and potential advantage in biomedical application.

The study of targeted blocking SDF-1/CXCR4 signaling pathway with three antagonists on MMPs, type II collagen, and aggrecan levels in articular cartilage of guinea pigs

Objective

To explore the possibility and mechanism of targeted blocking SDF-1/CXCR4 signaling pathway using three antagonists TN14003, T140, and AMD3100 in vivo, and to investigate the function of three antagonists in delay degeneration process of articular cartilage.

Methods

Ninety-six male Duncan-Hartley guinea pigs (6 months old) were divided into groups A, B, C, and D randomly. Alzet trace pump was implanted in the back subcutaneous tissue of pigs in group A, and TN14003 with concentration of 180 μg/ml was pumped every day. Alzet trace pump was implanted in the back subcutaneous tissue of pigs in group B, and T140 with concentration of 180 μg/ml was pumped every day. Alzet trace pump was implanted in the back subcutaneous tissue of pigs in group C, and AMD3100 with concentration of 180 μg/ml was pumped every day. Hartley guinea pigs in group D remained untreated as the blank control group. At 2, 4, 6, 8, 10, and 12 weeks of treatment, 5 to 8 animals in each group were randomly chosen for blood collection via cardiac puncture. SDF-1 content using enzyme-linked immunosorbent assay (ELISA). At 12 weeks, all guinea pigs were sacrificed by injecting pentobarbital sodium (30 mg/kg) into the peritoneal cavity. Cartilages from the tibial plateau in each group were harvested for PCR testing and western blot analysis. SPSS19.0 was used for data analysis.

Results

Result of ELISA: the serum levels of SDF-1 of groups A, B, and C decreased gradually with time. Significant drop of SDF-1 level was seen in group A while increased SDF-1 was shown in group D. At the same time, the serum levels of SDF-1 of the group A were significantly lower than that of group B; those of group B were significantly lower than that of group C, which was significantly lower than that of group D, and their difference is statistically significant (P < 0.05). Real time quantitative PCR result: The mRNA levels of MMPs in group A were significantly lower than group B, and those of group B were significantly lower than group C, which was significantly lower than group D, and there was statistically significant (P < 0.05). The mRNA levels of type II collagen, aggrecan in group A were significantly more than group B; those of group B were significantly more than group C, which was significantly more than group D, and the difference was statistically significant (P < 0.05). H&E staining result: cartilage of group C was more significantly degenerative than other groups.

Conclusions

The three antagonists can target SDF-1/CXCR4 signaling pathway in vivo, reduce the expression and secretion of MMP-3, MMP-9, and MMP-13 in cartilage tissue, and reduce the degradation of collagen II and aggregating proteoglycan, thus delaying the degeneration of articular cartilage, of which TN14003 has the strongest regulatory effect. Targeted blockade of SDF-1/CXCR4 signaling pathway by TN14003 in vivo delays articular cartilage degeneration more effectively than T140 and AMD3100.

Maintenance of Nucleolar Homeostasis by CBX4 Alleviates Senescence and Osteoarthritis

CBX4, a component of polycomb repressive complex 1 (PRC1), plays important roles in the maintenance of cell identity and organ development through gene silencing. However, whether CBX4 regulates human stem cell homeostasis remains unclear. Here, we demonstrate that CBX4 counteracts human mesenchymal stem cell (hMSC) aging via the maintenance of nucleolar homeostasis. CBX4 protein is downregulated in aged hMSCs, whereas CBX4 knockout in hMSCs results in destabilized nucleolar heterochromatin, enhanced ribosome biogenesis, increased protein translation, and accelerated cellular senescence. CBX4 maintains nucleolar homeostasis by recruiting nucleolar protein fibrillarin (FBL) and heterochromatin protein KRAB-associated protein 1 (KAP1) at nucleolar rDNA, limiting the excessive expression of rRNAs. Overexpression of CBX4 alleviates physiological hMSC aging and attenuates the development of osteoarthritis in mice. Altogether, our findings reveal a critical role of CBX4 in counteracting cellular senescence by maintaining nucleolar homeostasis, providing a potential therapeutic target for aging-associated disorders.

Undenatured Type II Collagen (UC-II) in Joint Health and Disease: A Review on the Current Knowledge of Companion Animals

OA is quite common in companion animals, especially in large breed dogs and horses. Collagen, the most abundant protein of mammals, has specific connective tissue types for skin, bones, reticulate, basal lamina, bones, cell surfaces, while type II collagen (UC-II) forms the main structure of cartilage tissue. Even at the smaller dosages, UC-II has also been reported to be more effective than the glucosamine and chondroitin sulfate supplements, which are the supplements most frequently used in the market. In this review, we summarize the effects of UC-II on joint health and function in health and disease conditions in companion animals.

Protective Effect of Alendronate on Lumbar Facet Degeneration in Ovariectomized Rats

Background

Facet joint degeneration (FJD) is a potential source of lower back pain, and estrogen deficiency can accelerate FJD. The present study aimed to investigate the effects of alendronate (ALN) on FJD induced by ovariectomy (OVX) in rats.

Material/Methods

Thirty female Sprague-Dawley rats underwent either bilateral OVX (n=20) or sham surgery (n=10). The OVX rats subsequently received either subcutaneous ALN (70 μg/kg/week) or vehicle for 12 weeks. Subchondral bone mass and microarchitecture were evaluated by micro-computed tomography. Cartilage degradation was evaluated by toluidine blue staining and histological scoring.

Results

Compared with the Sham group, the OVX group had significantly decreased bone mineral density, bone volume/trabecular volume, and trabecular thickness, significantly increased trabecular separation in subchondral bone, and significantly higher histological score for cartilage degeneration, particularly loss of cartilage thickness. ALN treatment significantly reversed the changes in subchondral bone, preserved cartilage thickness, and reduced the histological score. Immunohistochemical analyses showed significantly decreased expression of ADAMTS-4, MMP-13, and caspase-3 in the OVX+ALN group compared with the OVX group.

Conclusions

Treatment with ALN suppressed bone loss, subchondral bone architecture deterioration, and cartilage degeneration in OVX rats, which can be explained by roles of ALN in preservation of subchondral bone mass and microarchitecture, and counteraction of catabolism and chondrocyte apoptosis in cartilage.

Four Antioxidant Peptides from Protein Hydrolysate of Red Stingray (Dasyatis akajei) Cartilages: Isolation, Identification, and In Vitro Activity Evaluation

In the work, water-soluble proteins of red stingray (Dasyatis akajei) cartilages were extracted by guanidine hydrochloride and hydrolyzed using trypsin. Subsequently, four antioxidant peptides (RSHP-A, RSHP-B, RSHP-C, and RSHP-D) were isolated from the water-soluble protein hydrolysate while using ultrafiltration and chromatographic techniques, and the amino acid sequences of RSHP-A, RSHP-B, RSHP-C, and RSHP-D were identified as Val-Pro-Arg (VPR), Ile-Glu-Pro-His (IEPH), Leu-Glu-Glu--Glu-Glu (LEEEE), and Ile-Glu-Glu-Glu-Gln (IEEEQ), with molecular weights of 370.46 Da, 494.55 Da, 647.64 Da, and 646.66 Da, respectively. VPR, IEPH, LEEEE, and IEEEQ exhibited good scavenging activities on the DPPH radical (EC50 values of 4.61, 1.90, 3.69, and 4.01 mg/mL, respectively), hydroxyl radical (EC50 values of 0.77, 0.46, 0.70, and 1.30 mg/mL, respectively), superoxide anion radical (EC50 values of 0.08, 0.17, 0.15, and 0.16 mg/mL, respectively), and ABTS cation radical (EC50 values of 0.15, 0.11, 0.19, and 0.18 mg/mL, respectively). Among the four isolated antioxidant peptides, IEPH showed the strongest reducing power and lipid peroxidation inhibition activity, but LEEEE showed the highest Fe2+-chelating ability. The present results suggested that VPR, IEPH, LEEEE, and IEEEQ might have the possibility of being an antioxidant additive that is used in functional food and pharmaceuticals.

Up-regulation of FOXD1 by YAP alleviates senescence and osteoarthritis

Cellular senescence is a driver of various aging-associated disorders, including osteoarthritis. Here, we identified a critical role for Yes-associated protein (YAP), a major effector of Hippo signaling, in maintaining a younger state of human mesenchymal stem cells (hMSCs) and ameliorating osteoarthritis in mice. Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated protein 9 nuclease (Cas9)-mediated knockout (KO) of YAP in hMSCs resulted in premature cellular senescence. Mechanistically, YAP cooperated with TEA domain transcriptional factor (TEAD) to activate the expression of forkhead box D1 (FOXD1), a geroprotective protein. YAP deficiency led to the down-regulation of FOXD1. In turn, overexpression of YAP or FOXD1 rejuvenated aged hMSCs. Moreover, intra-articular administration of lentiviral vector encoding YAP or FOXD1 attenuated the development of osteoarthritis in mice. Collectively, our findings reveal YAP–FOXD1, a novel aging-associated regulatory axis, as a potential target for gene therapy to alleviate osteoarthritis.

The Hippo signalling effector YAP and the transcription factor FOXD1 play a role in alleviating cellular senescence and osteoarthritis, identifying the YAP-FOXD1 axis as a potential therapeutic target for aging-associated disorders.

Stem cell aging contributes to aging-associated degenerative diseases. Studies aiming to characterize the mechanisms of stem cell aging are critical for obtaining a comprehensive understanding of the aging process and developing novel strategies to treat aging-related diseases. As a prevalent aging-associated chronic joint disorder, osteoarthritis is a leading cause of disability. Senescent mesenchymal stem cells (MSCs) residing in the joint may be a critical target for the prevention of osteoarthritis; however, the key regulators of MSC senescence are little known, and targeting aging regulatory genes for the treatment of osteoarthritis has not yet been reported. Here, we show that Yes-associated protein (YAP), a major effector of Hippo signaling, represses human mesenchymal stem cell (hMSC) senescence through transcriptional up-regulation of forkhead box D1 (FOXD1). Lentiviral gene transfer of YAP or FOXD1 can rejuvenate aged hMSCs and ameliorate osteoarthritis symptoms in mouse models. We propose that the YAP–FOXD1 axis is a novel target for combating aging-associated diseases.

Physicochemical properties of acid- and pepsin-soluble collagens from the cartilage of Siberian sturgeon

To look for the collagen alternatives of mammalian cartilages from aquatics and their by-products, acid-soluble collagen (ASC-SC) and pepsin-soluble collagen (PSC-SC) were extracted from cartilages of Siberian sturgeon (Acipenser baerii) with yields of 27.13 ± 1.15 and 14.69 ± 0.85% on dry weight basis. ASC-SC and PSC-SC had glycine as the major amino acid with the contents of 326.8 and 327.5 residues 1000 residues^-1, and their contents of proline and hydroxyproline were 205.9 and 208.0 residues 1000 residues^-1. ASC-SC and PSC-SC comprised type I collagen ([α1(I)]₂α2(I)) and type II collagen ([α1(II)]₃) on the literatures and results of amino acid composition, SDS-PAGE pattern, UV, and FTIR spectra. Meanwhile, FTIR spectra data indicated that there were more hydrogen bonds in ASC-SC and more intermolecular crosslinks in PSC-SC. The maximum transition temperature (T_max) of the ASC (28.3 °C) and PSC (30.5 °C) was lower than those of collagens from mammalian cartilages (> 37 °C). ASC-SC and PSC-SC showed high solubility in the acidic pH ranges and the solubility decreased in the presence of NaCl at concentrations above 3%. Zeta potential studies indicated that both ASC-SC and PSC-SC exhibited a net zero charge at pH 6.30 and 6.32. SEM results indicated that ASC-SC and PSC-SC presented irregular dense sheet-like film linked by random-coiled filaments. Therefore, collagens from Siberian sturgeon cartilages might be the suitable alternatives of the collagens of mammal cartilages as functional ingredient to treat some diseases.