Effect of Fucoidan on Anterior Cruciate Ligament Transection and Medial Meniscectomy Induced Osteoarthritis in High-Fat Diet-Induced Obese Rats

A comparative study of the hypolipidemic effects and mechanisms of action of Laminaria japonica- and Ascophyllum nodosum-derived fucoidans in apolipoprotein E-deficient mice

The structural characteristics of fucoidans exhibit species and regional diversity. Previous studies have demonstrated that Laminaria japonica- and Ascophyllum nodosum-derived fucoidans have type I and type II fucosyl chains, respectively. These chemical differences may contribute to distinct hypolipidemic effects and mechanisms of action. Chemical analysis demonstrated that the percentage contents of sulfate, glucuronic acid, and galactose were higher in L. japonica-derived fucoidans than those of A. nodosum-derived fucoidans. In hyperlipidemic apolipoprotein E-deficient mice, both A. nodosum- and L. japonica-derived fucoidans significantly decreased the plasma and hepatic levels of total cholesterol and triglyceride, leading to the reduction of atherosclerotic plaques. Western blotting experiments demonstrated that these fucoidans significantly enhanced the expression and levels of scavenger receptor B type 1, cholesterol 7 alpha-hydroxylase A1, and peroxisome proliferator-activated receptor (PPAR)-α, contributing to circulating lipoprotein clearance and fatty acid degradation, respectively. Differentially, L. japonica-derived fucoidan significantly increased the LXR/ATP-binding cassette G8 signaling pathway in the small intestine, as revealed by real-time quantitative PCR, which may lead to further cholesterol and other lipid excretion. Collectively, these data are useful for understanding the hypolipidemic mechanisms of action of seaweed-derived fucoidans, and their potential application for the prevention and/or treatment of atherosclerotic cardiovascular diseases.

Laminaria japonica Aresch-Derived Fucoidan Ameliorates Hyperlipidemia by Upregulating LXRs and Suppressing SREBPs

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, and hyperlipidemia is one major inducing factor of CVD. It is worthy to note that fucoidans are reported to have hypolipidemic activity with species specificity; however, the underlying mechanisms of action are far from clarification. This study is aimed at investigating the plasma lipid-lowering mechanisms of the fucoidan from L. japonica Aresch by detecting the levels of hepatic genes that are involved in lipid metabolism. Our results demonstrated that the fucoidan F3 significantly lowered total cholesterol and triglyceride in C57BL/6J mice fed a high-fat diet. In the mouse liver, fucoidan F3 intervention significantly increased the gene expression of peroxisome proliferator-activated receptor (PPAR) α, liver X receptor (LXR) α and β, and ATP-binding cassette transporter (ABC) G1 and G8 and decreased the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), low-density lipoprotein receptor, cholesterol 7 alpha-hydroxylase A1, and sterol regulatory element-binding protein (SREBP) 1c and SREBP-2. These results demonstrated that the antihyperlipidemic effects of fucoidan F3 are related to its activation of PPARα and LXR/ABC signaling pathways and inactivation of SREBPs. In conclusion, fucoidan F3 may be explored as a potential compound for prevention or treatment of lipid disorders.

Fucoidan from Cladosiphon okamuranus enhances antioxidant activity and prevents reproductive dysfunction in polystyrene microplastic-induced male rats

Plastic pollution, including microplastic, has emerged as a severe environmental and public health problem. The health risks, especially in the case of reproductive damage caused by polystyrene microplastic (PS-MP) exposure, are emerging problems that need to be solved. This study aimed to investigate the effects of fucoidan extracted from Cladosiphon okamuranus on the polystyrene microplastic-induced oxidative stress of the Leydig (LC540) cells and reproductive damage in male rats. The oxidative stress of the LC540 cells and reproductive damage in the rats were induced by PS-MP. The fucoidan treatment reduces nitric oxide (NO) and reactive oxygen species generation in the LC540 cells. In the animal study, fucoidan treatment enhanced enzymatic antioxidant activities (glutathione peroxidase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione reductase) and reduced malondialdehyde and nitric oxide production. Fucoidan supplementation also downregulates tumor necrosis factor-alpha, interleukin-6, and caspase-3 expression. Additionally, fucoidan upregulates testosterone levels, prevents the reduction of epithelium thickness, and reduces the area of the seminiferous tubule lumen. According to these conditions, fucoidan from Cladosiphon okamuranus prevents reproductive damage by downregulating oxidative stress and pro-inflammatory cytokines. Therefore, fucoidan can be used as a source of food supplements or functional food ingredients for reproductive or testicular damage management.

The GM-CSF/CCL17 pathway in obesity-associated osteoarthritic pain and disease in mice

OBJECTIVES

We have previously identified a granulocyte macrophage-colony stimulating factor (GM-CSF)/C-C motif ligand 17 (CCL17) pathway in monocytes/macrophages, in which GM-CSF regulates the formation of CCL17, and it is important for an experimental osteoarthritis (OA) model. We explore here additional OA models, including in the presence of obesity, such as a requirement for this pathway.

DESIGN

The roles of GM-CSF, CCL17, CCR4, and CCL22 in various experimental OA models, including those incorporating obesity (eight-week high-fat diet), were investigated using gene-deficient male mice. Pain-like behavior and arthritis were assessed by relative static weight distribution and histology, respectively. Cell populations (flow cytometry) and cytokine messenger RNA (mRNA) expression (qPCR) in knee infrapatellar fat pad were analyzed. Human OA sera were collected for circulating CCL17 levels (ELISA) and OA knee synovial tissue for gene expression (qPCR).

RESULTS

We present evidence that: i) GM-CSF, CCL17, and CCR4, but not CCL22, are required for the development of pain-like behavior and optimal disease in three experimental OA models, as well as for exacerbated OA development due to obesity, ii) obesity alone leads to spontaneous knee joint damage in a GM-CSF- and CCL17-dependent manner, and iii) in knee OA patients, early indications are that BMI correlates with a lower Oxford Knee Score (r = -0.458 and p = 0.0096), with elevated circulating CCL17 levels (r = 0.2108 and p = 0.0153) and with elevated GM-CSF and CCL17 gene expression in OA synovial tissue.

CONCLUSIONS

The above findings indicate that GM-CSF, CCL17, and CCR4 are involved in obesity-associated OA development, broadening their potential as targets for possible treatments for OA.

BASP1 knockdown suppresses chondrocyte apoptosis and extracellular matrix degradation in vivo and in vitro: A possible therapeutic approach for osteoarthritis

Osteoarthritis(OA) is an age-related degenerative disease involving chondrocyte apoptosis and extracellular matrix(ECM) degradation.Brain acid soluble protein 1(BASP1) has been reported to induce apoptosis.Thus, we speculated that BASP1 might regulate OA progression by inducing apoptosis, which is also the purpose of this study.The cartilage of the knee joint was collected from OA patients who received the joint replacement.In OA cartilage tissue,we found BASP1 expression was highly expressed, which inferred that BASP1 might be involved in OA.To validate our hypothesis, destabilization of the medial meniscus (DMM) surgery-induced male C57BL/6mice and interleukin-1β (IL-1β)-treated human chondrocytes were used to mimic the OA environment.BASP1 knockdown in mice and chondrocytes was achieved by adenovirus carried with BASP1-specific shRNA.High expression of BASP1 was observed in OA mice, which was also verified in IL-1β-treated chondrocytes.The potential mechanism of BASP1 in OA was further explored in vitro.BASP1 knockdown alleviated IL-1β-induced apoptosis and ECM degradation, as reflected by the decreased number of apoptotic cells and matrix metalloproteases 13 expression,and the increased collagen II expression.Our findings indicated that BASP1 knockdown alleviated OA progression by inhibiting apoptosis and ECM degradation, suggesting that inhibiting BASP1 may be a potentially applicable method for preventing OA.

A review focusing on the benefits of plant-derived polysaccharides for osteoarthritis

Osteoarthritis (OA) is a chronic joint disease characterized by progressive cartilage degeneration, which imposes a heavy physical and financial burden on the middle-aged and elderly population. As the pathogenesis of OA has not been fully elucidated, it is of great importance to develop targeted therapeutic or preventive medications. Traditional therapeutic drugs, such as non-steroidal anti-inflammatory drugs, steroids and opioids, have significant side effects, making the exploration for safe and effective alternative therapeutic drugs urgent. In recent years, many studies have reported the role of plant-derived polysaccharides in anti-inflammation, anti-oxidation, regulation of chondrocyte metabolism and proliferation, and cartilage protection, and have demonstrated their great potential in the treatment of OA. Therefore, by focusing on studies related to the intervention of plant-derived polysaccharides in OA, including in vivo and in vitro experiments, this review aimed to classify and summarize the existing research findings according to different mechanisms of action. In addition, reports on plant-derived polysaccharides as nanoparticles were also explored. Then, candidate monomers and theoretical bases were provided for the further development and application of novel drugs in the treatment of OA.

Protective effect of ethanolic extract of Echinacea purpurea contained nanoparticles on meniscal/ligamentous injury induced osteoarthritis in obese male rats

Osteoarthritis (OA) is a chronic degenerative joint disease associated with age, mechanical stress, and obesity. Echinacea purpurea is a medicinal plant that shows good anti-inflammatory, antioxidant, and immunomodulatory activities. In this study, Echinacea purpurea ethanol extract nanoparticles (Nano-EE) were prepared by encapsulating Echinacea purpurea ethanol extract (EE) in chitosan-silica nanoparticles. Obesity (OB) in Sprague-Dawley (SD) rats was induced by fed 40% high-fat diet and then anterior cruciate ligament and meniscus injury were performed to induce OA. The rats got different doses of samples by oral gavage. The encapsulation efficiency and loading capacity of Nano-EE were 69.1% and 36.1%, respectively. The average size, polydispersity index (PDI), and zeta potential (ZP) of the Nano-EE were 145 ± 11 nm, 0.24 ± 0.01, − 4.57 ± 0.44 mV, respectively. Furthermore, electron microscopic images showed that the particles were spherical and were slightly agglomerated. Moreover, it showed that the leptin content, expression of MMPs, cytokines level, NF-κB level, and iNOS production were decreased whereas collagen II expression was increased after treatment. Besides, Nano-EE ameliorated the pain caused by OA and reduced the proteoglycan loss in cartilage. These results indicated that encapsulated EE (Nano-EE) can ameliorate OA with a low dosage and are more effective than unencapsulated EE.

Algal polysaccharides and derivatives as potential therapeutics for obesity and related metabolic diseases

The potential and challenges of algal polysaccharides and their derivatives as potential therapeutic agents for obesity and its related metabolic diseases.

Dietary fucoidan extracted from macroalgae Saccharina japonica alleviate the hepatic lipid accumulation of black seabream (Acanthopagrus schlegelii)

The use of an artificial diet often leads to the increase of risk factors for the development of liver diseases, such as hepatic lipid accumulation (HLA) in commercially cultured fish species. Our previous study showed that dietary Saccharina japonica could effectively alleviate HLA in black seabream (Acanthopagrus schlegelii), which may be linked predominantly to S. japonica fucoidan. Thus, a 56d nutritional trial was designed to investigate the effects of dietary fucoidan (CTRL, 0 g kg^-1; ASJ1, 0.75 g kg^-1; ASJ2, 3.00 g kg^-1) on growth performance, fillets nutritional values, and HLA of black seabream. Results showed that dietary fucoidan significantly improved the growth and the contents of n-3 polyunsaturated fatty acids (n-3PUFA) in fillets of black seabream. Moreover, dietary fucoidan improved HLA-related parameters, including reducing serum and liver lipid contents and the activity of aminotransferase. Meanwhile, histological analysis showed that dietary fucoidan reduced the area of hepatic lipid droplets in black seabream (P < 0.05). In addition, the transcriptomic analysis of differentially expressed gene (DEG) showed that all DEG in fatty acid metabolism, primary bile acid biosynthesis, and fatty acid biosynthesis were down-regulated, and all DEG in the regulation of autophagy were up-regulated in the ASJ1 group compared with CTRL group. Moreover, the metabolomic analysis of differentially expressed metabolite (DEM) found that lipid metabolism was the main type of KEGG pathway altered by fucoidan supplementation. Furthermore, the combined transcriptomic and metabolomic analysis found that dietary fucoidan mainly modified the lipid metabolic pathway of primary bile acid biosynthesis, glycerophospholipid metabolism, and arachidonic acid metabolism in the liver. In general, dietary fucoidan effectively alleviated HLA of black seabream, and the underlying mechanism may be ascribed to promoting the autophagy and inhibiting the synthesis of lipids and bile acids.

Cholesterol metabolism related genes in osteoarthritis

Cholesterol homeostasis plays a significant role in skeletal development and the dysregulation of cholesterol-related mechanism has been shown to be involved in the development of cartilage diseases including osteoarthritis (OA). Epidemiological studies have shown an association between elevated serum cholesterol levels and OA. Furthermore, abnormal lipid accumulation in chondrocytes as a result of abnormal regulation of cholesterol homeostasis has been demonstrated to be involved in the development of OA. Although, many in vivo and in vitro studies support the connection between cholesterol and cartilage degradation, the mechanisms underlying the complex interactions between lipid metabolism, especially HDL cholesterol metabolism, and OA remain unclear. The current review aims to address this problem and focuses on key molecular players of the HDL metabolism pathway and their role in ΟΑ pathogenesis. Understanding the complexity of biological processes implicated in OA pathogenesis, such as cholesterol metabolism, may lead to new targets for drug therapy of OA patients.

Hippocampus kuda protein hydrolysate improves male reproductive dysfunction in diabetic rats

The global prevalence of diabetes mellitus is rapidly increasing. This disease is associated with many complications including male reproductive dysfunctions and infertility. Seahorse ( Hippocampus kuda) is a marine teleost fish well known for its beneficial effects on the reproductive system in traditional Chinese medicine books. Recently, several studies have been shown that the enzymatic hydrolysate of seahorse has multiple pharmacological activities. This study aimed to investigate the seahorse peptide hydrolysate (SH) ameliorative effects on the diabetic-induced male reproductive dysfunction in rat models. The in vivo studies were carried out with three different doses of SH (4, 8, and 20 mg/kg) and the diabetes condition was induced by administrating with streptozotocin (35 mg/kg) and fed a 40% high-fat diet. Seahorse hydrolysate (20 mg/kg) inhibited lipid peroxidation, increased antioxidant enzyme activity, and restored seminiferous tubules morphology in testis. Moreover, it improved reproductive dysfunction by increasing the level of testosterone, follicle-stimulating hormone, luteinizing hormone, sperm count, and motility. According to these results, we suggested that SH exhibited amelioration effects on the reproductive dysfunction.

Study of fucoidans as natural biomolecules for therapeutical applications in osteoarthritis

Osteoarthritis (OA) is the most prevalent articular chronic disease. Although, to date there is no cure for OA. Fucoidans, one of the main therapeutic components of brown algae, have emerged as promising molecules in OA treatment. However, the variability between fucoidans makes difficult the pursuit of the most suitable candidate to target specific pathological processes. By an in vitro experimental approach in chondrocytes and fibroblast-like synoviocytes, we observed that chemical composition of fucoidan, and specifically the phlorotannin content and the ratio sulfate:fucose, seems critically relevant for its biological activity. Nonetheless, other factors like concentration and molecular weight of the fucoidan may influence on its beneficial effects. Additionally, a cell-type dependent response was also detected. Thus, our results shed light on the potential use of fucoidans as natural molecules in the treatment of key pathological processes in the joint that favor the development of rheumatic disorders as OA.

Caulerpa lentillifera Polysaccharides-Rich Extract Reduces Oxidative Stress and Proinflammatory Cytokines Levels Associated with Male Reproductive Functions in Diabetic Mice

Diabetes mellitus is a chronic metabolic disease that is positively correlated with reproductive dysfunction. Caulerpa lentillifera is an edible green alga with antioxidant and anti-diabetic properties. This study aims to evaluate the ameliorative effects of a polysaccharides-rich extract from C. lentillifera on the reproductive dysfunctions of diabetic male BALB/c mice induced by a high-fat diet (HFD) supplemented with intraperitoneal injections of streptozotocin (STZ). C. lentillifera was obtained from hot water and converted into a powder form (C. lentillifera extract (CLE)) by freeze drying. Mice were fed an HFD for 4 weeks before supplementing with STZ (30 mg/kg). The diabetic mice were divided into five groups, including a control group, a diabetic (DM) group, a DM with administration of a low-dose CLE treatment (DM+CLE1, 600 mg/kg), a DM with administration of a high-dose of CLE (DM+CLE2, 1000 mg/kg) and a DM with metformin treatment as a positive control (DM+Met, 200 mg/kg) for 6 weeks. The results showed that the CLE administration improved hyperglycemia and insulin resistance. Proinflammatory cytokines such as interleukin-1β and tumor necrosis factor-α were found to decrease in the CLE-treated groups. Additionally, CLE was shown to improve sperm motility and testis morphology. Based on the results, it was confirmed that the polysaccharides-rich extract from C. lentillifera extract was able to prevent diabetes-induced male reproductive dysfunction.

Fucoidan Inhibits NLRP3 Inflammasome Activation by Enhancing p62/SQSTM1-Dependent Selective Autophagy to Alleviate Atherosclerosis

NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation contributes to the progression of atherosclerosis, and autophagy inhibits inflammasome activation by targeting macrophages. We investigated whether fucoidan, a marine sulfated polysaccharide derived from brown seaweeds, could reduce NLRP3 inflammasome activation by enhancing sequestosome 1 (p62/SQSTM1)-dependent selective autophagy to alleviate atherosclerosis in high-fat-fed ApoE-/- mice with partial carotid ligation and differentiated THP-1 cells incubated with oxidized low-density lipoprotein (oxLDL). Fucoidan significantly ameliorated lipid accumulation, attenuated progression of carotid atherosclerotic plaques, deregulated the expression of NLRP3 inflammasome, autophagy receptor p62, and upregulated microtubule-associated protein light chain 3 (LC3)-II/I levels. Transmission electron microscopy and GFP-RFP-LC3 lentivirus transfection further demonstrated that fucoidan could activate autophagy. Mechanistically, fucoidan remarkably inhibited NLRP3 inflammasome activation, which was mostly dependent on autophagy. The inhibitory effects of fucoidan on NLRP3 inflammasome were enhanced by autophagy activator rapamycin (Rapa) and alleviated by autophagy inhibitor 3-methyladenine (3-MA). Fucoidan promoted the colocalization of NLRP3 and p62. Knockdown of p62 and ATG5 by small interfering RNA significantly reduced the inhibitory effects of fucoidan treatment on NLRP3 inflammasome. The data suggest that fucoidan can inhibit NLRP3 inflammasome activation by enhancing p62/SQSTM1-dependent selective autophagy to alleviate atherosclerosis.

Blue Mussel (Mytilus edulis) Water Extract Ameliorates Inflammatory Responses and Oxidative Stress on Osteoarthritis in Obese Rats

Purpose

To investigate the effects of Mytilus edulis water extract (MWE) on an anterior cruciate ligament transection and a partial medial meniscectomy surgery to induced osteoarthritis (OA) with the high-fat diet (HFD)-induced obese rats.

Methods

The male Sprague-Dawley rats were fed with HFD for 4 weeks before surgery. The OA rats were orally administered with MWE (108.5, 217.0, and 542.5 mg/kg) for 6 weeks.

Results

The administration of MWE affected weight loss, triglycerides content, and total cholesterol level. MWE also enhanced the activity of superoxide dismutase and decreased lipid peroxidation degree. Moreover, MWE reduced proinflammatory cytokines level, alleviated inflammation and swelling of the osteoarthritic knee, and reduced loss of proteoglycan in articular cartilage tissue.

Conclusion

MWE suppressed proinflammatory mediators and attenuated the cartilage degradation and pain in osteoarthritis rats under obesity condition. Therefore, MWE has the potential to act as an alternative for osteoarthritis treatment.

Sea cucumber Cucumaria frondosa fucoidan inhibits osteosarcoma adhesion and migration by regulating cytoskeleton remodeling

Osteosarcoma (OS) has been demonstrated to be difficult to cure due to its potently malignant metastasis. Therefore, new therapeutic approaches blocking the metastatic potential of OS are urgently required to improve the outcomes for OS patients. In the present study, the anti-metastatic capacity of sea cucumber (Cucumaria frondosa) fucoidan (Cf-Fuc) was evaluated on osteosarcoma cells by cell adhesion assay, Transwell assay and U2OS cell migration assay. The underlying mechanism on the dynamic remodeling of the cytoskeleton was also explored. The present data indicated that Cf-Fuc could block the U2OS osteosarcoma cell adhesion to fibronectin and significantly inhibit U2OS cell migration. Cf-Fuc greatly impaired the migration capacity of U2OS cells, and the migrated distance and velocity of Cf-Fuc-treated cells were markedly reduced. Also, Cf-Fuc could impair the dynamic remodeling of the cytoskeleton possibly by suppressing the phosphorylation of focal adhesion kinase and paxillin, as well as the activation of the Rac1/PAK1/LIMK1/cofilin signaling axis. Collectively, the present findings provide a novel therapeutic potential of C. frondosa fucoidan for osteosarcoma metastasis.

Dietary Saturated Fatty Acids Modulate Pain Behaviour in Trauma-Induced Osteoarthritis in Rats

Osteoarthritis (OA) is a degenerative condition of joints, causing pain and swelling, and can be caused or worsened by trauma and obesity. The objectives of this study were to determine whether pain behaviour and progression of OA were increased in rats with trauma-induced OA fed dietary saturated fatty acids (SFA). Male Wistar rats were fed either a corn starch diet (C) or high-carbohydrate high-fat diet (H) with either 20% beef tallow or SFA (lauric (HLA), myristic (HMA), palmitic (HPA) or stearic (HSA) acids) for 16 weeks prior to and 8 weeks after excision of the medial meniscus of right knee joint to initiate OA when pain behaviour, glial activity, progression of knee OA, inflammatory mediators and signs of metabolic syndrome were assessed. Rats fed beef tallow, palmitic or stearic acids showed increased pain symptoms characterised by decreased hind paw/limb withdrawal thresholds and grip strengths and increased spinal astrogliosis and microgliosis compared to rats fed lauric or myristic acids. However, the severity of OA joint damage was unchanged by these dietary manipulations. We conclude that pain symptoms of trauma-induced OA in rats worsen with increased dietary beef tallow or palmitic or stearic acids, but improve with lauric or myristic acids, despite unchanged OA cartilage damage.

A dietary polysaccharide from Eucheuma cottonii downregulates proinflammatory cytokines and ameliorates osteoarthritis-associated cartilage degradation in obese rats

Osteoarthritis (OA) is a common form of arthritis, which is characterized by the degeneration of articular cartilage, leading to joint dysfunction. Oral drug therapy seems to ameliorate some signs and symptoms of OA, but may be accompanied by side effects and does not appear to be effective long-term. Seaweed has received much attention for pharmacological application due to its various biomedical properties, including the anti-inflammation, antitumor, and antioxidant effects. This study investigated the ameliorative effects of a dietary polysaccharide from Eucheuma cottonii extract (ECE) on an anterior cruciate ligament transection with partial medial meniscectomy surgery (ACLT+MMx) to induce OA in high-fat diet (HFD)-induced obese rats. Male Sprague-Dawley rats were fed an HFD for 12 weeks before ACLT+MMx surgery, after which they were administered a daily oral gavage of saline (Sham, OB Sham, and OBOA) and either low-dose ECE (100 mg per kg body weight), high-dose ECE (400 mg per kg body weight), or glucosamine sulfate as a positive control (OBOAGS; 200 mg per kg body weight) for 5 weeks. Treatment with ECE decreased the body weight, triglyceride and total cholesterol (TC) levels, and the TC/high-density lipoprotein (HDL)-C ratio in the obese rats. Additionally, ECE downregulated the expression of proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, and leptin, and suppressed nuclear factor-kappa B and extracellular-signal-regulated kinase-1/2 expression, resulting in a decrease in the levels of matrix metalloproteinase (MMP)-1 and MMP-13 and prostaglandin-E₂ and attenuated cartilage degradation. These results demonstrate that the dietary polysaccharide from ECE can suppress OA development in obese rats, suggesting its potential efficacy as a promising candidate for OA treatment.

Development of Injectable Fucoidan and Biological Macromolecules Hybrid Hydrogels for Intra-Articular Delivery of Platelet-Rich Plasma

Platelet-rich plasma (PRP) is rich in growth factors and has commonly been utilized in the repair and regeneration of damaged articular cartilage. However, the major drawbacks of direct PRP injection are unstable biological fixation and fast or burst release of growth factors. Fucoidan is a heparinoid compound that can bind growth factors to control their release rate. Furthermore, fucoidan can reduce arthritis through suppressing inflammatory responses and thus it has been reported to prevent the progression of osteoarthritis, promote bone regeneration and accelerate healing of cartilage injury. Injectable hydrogels can be used to deliver cells and growth factors for an alternative, less invasive treatment of cartilage defects. In this study, hyaluronic acid (HA) and fucoidan (FD) was blended with gelatin (GLT) and the GLT/HA/FD hybrid was further cross-linked with genipin (GP) to prepare injectable GP-GLT/HA/FD hydrogels. The gelation rate was affected by the GP, GLT, HA and FD concentrations, as well as the pH values. The addition of HA and FD to GLT networks improved the mechanical strength of the hydrogels and facilitated the sustained release of PRP growth factors. The GP-GLT/HA/FD hydrogel showed adequate injectability, shape-persistent property and strong adhesive ability, and was more resistant to enzymatic degradation. The PRP-loaded GP-GLT/HA/FD hydrogel promoted cartilage regeneration in rabbits, which may lead to an advanced PRP therapy for enhancing cartilage repair.