Expression of Genes Encoding Extracellular Matrix Macromolecules and Metalloproteinases in Avian Tibial Dyschondroplasia

miR-181b-1-3p affects the proliferation and differentiation of chondrocytes in TD broilers through the WIF1/Wnt/β-catenin pathway

Thiram is a plant fungicide, its excessive use has exceeded the required environmental standards. It causes tibial dyschondroplasia (TD) in broilers which is a common metabolic disease that affects the growth plate of tibia bone. It has been studied that many microRNAs (miRNAs) are involved in the differentiation of chondrocytes however, their specific roles and mechanisms have not been fully investigated. The selected features of tibial chondrocytes of broilers were studied in this experiment which included the expression of miR-181b-1-3p and the genes related to WIF1/Wnt/β-catenin pathway in chondrocytes through qRT-PCR, western blot and immunofluorescence. The correlation between miR-181b-1-3p and WIF1 was determined by dual luciferase reporter gene assay whereas, the role of miR-181b-1-3p and WIF1/Wnt/β-catenin in chondrocyte differentiation was determined by mimics and inhibitor transfection experiments. Results revealed that thiram exposure resulted in decreased expression of miR-181b-1-3p and increased expression of WIF1 in chondrocytes. A negative correlation was also observed between miR-181b-1-3p and WIF1. After overexpression of miR-181b-1-3p, the expression of ACAN, β-catenin and Col2a1 increased but the expression of GSK-3β decreased. It was observed that inhibition of WIF1 increased the expression of ALP, β-catenin, Col2a1 and ACAN but decreased the expression of GSK-3β. It is concluded that miR-181b-1-3p can reverse the inhibitory effect of thiram on cartilage proliferation and differentiation by inhibiting WIF1 expression and activating Wnt/β-catenin signaling pathway. This study provides a new molecular target for the early diagnosis and possible treatment of TD in broilers.

Transcriptome-based biomarker gene screening and evaluation of the extracellular fatty acid-binding protein (Ex-FABP) on immune and angiogenesis-related genes in chicken erythrocytes of tibial dyschondroplasia

BACKGROUND

Tibial dyschondroplasia (TD) is a bone disorder in which dead chondrocytes accumulate as a result of apoptosis and non-vascularization in the tibial bone of broiler chickens. The pathogenicity of TD is under extensive research but is yet not fully understood. Several studies have linked it to apoptosis and non-vascularization in the tibial growth plate (GP). We conceived the idea to find the differentially expressed genes (DEGs) in chicken erythrocytes which vary in expression over time using a likelihood-ratio test (LRT). Thiram was used to induce TD in chickens, and then injected Ex-FABP protein at 0, 20, and 50 μg^.kg^-1 to evaluate its therapeutic effect on 30 screened immunity and angiogenesis-related genes using quantitative PCR (qPCR). The histopathology was also performed in TD chickens to explore the shape, circularity, arrangements of chondrocytes and blood vessels.

RESULTS

Clinical lameness was observed in TD chickens, which decreased with the injection of Ex-FABP. Histopathological findings support Ex-FABP as a therapeutic agent for the morphology and vascularization of affected chondrocytes in TD chickens. qPCR results of 10 immunity (TLR2, TLR3, TLR4, TLR5, TLR7, TLR15, IL-7, MyD88, MHCII, and TRAF6) and 20 angiogenesis-related genes (ITGAV, ITGA2, ITGB2, ITGB3, ITGA5, IL1R1, TBXA2R, RPL17, F13A1, CLU, RAC2, RAP1B, GIT1, FYN, IQGAP2, PTCH1, NCOR2, VAV-like, PTPN11, MAML3) regulated when Ex-FABP is injected to TD chickens.

CONCLUSION

Immunity and angiogenesis-related genes can be responsible for apoptosis of chondrocytes and vascularization in tibial GP. Injection of Ex-FABP protein to thiram induced TD chickens decrease the chondrocytes damage and improves vascularization.

Taurine is an effective therapy against thiram induced tibial dyschondroplasia via HIF-1α/VEGFA and β-catenin/ GSK-3β pathways in broilers

Thiram causes tibial dyschondroplasia in broilers, leading to a significant economic loss in the poultry industry. Our study explored the effects of taurine in thiram induced tibial dyschondroplasia (TD) through in vivo and in vitro approches. In in vivo study, thiram resulted in lameness disorder, low production parameters ALP, ACP, and a high level of NOS. While, the taurine exhibited promising effect by reducing lameness, increasing ALP, ACP levels, and significantly lowering NOS level with the restoration of the growth plate. In in vitro study, thiram caused distortion and disintegration of chondrocytes. The CCK-8 technique revealed the lower cell activity in TD as compared with the treatment group. Even, the treatment and taurine groups had higher cell activity than control group. Also, the chondrocyte morphology progressively reverted to normal after taurine treatment. It might effectively decreased the symptoms of TD in broilers and their production performance. Further research found that the taurine effectively improved chondrocytes' cell viability and recovered lameness disorder by regulation of HIF-1α, VEGFA, and Wnt/β-catenin signaling pathways. In summary, these results indicate that taurine has a protective effect on thiram-induced broilers and it can enhance the growth activity by directly affecting the development of chondrocytes and blood vessels.

Recombinant glutathione-S-transferase A3 protein regulates the angiogenesis-related genes of erythrocytes in thiram induced tibial lesions

Tibial dyschondroplasia (TD) is a skeletal deformity disease in broilers that occurs when vascularization in the growth plate (GP) is below normal. Although, blood vessels have been reported to contribute significantly in bone formation. Therefore, in the current study, we have examined the mRNA expression of angiogenesis-related genes in erythrocytes of thiram induced TD chickens by qRT-PCR and performed histopathological analysis to determine regulatory effect of recombinant Glutathione-S-Transferase A3 (rGSTA3) protein in response to the destructive effect of thiram following the injection of rGSTA3 protein. Histopathology results suggested that, blood vessels of GPs were damaged in thiram induced TD chicken group (D), it also affected the area and density of blood vessels. In the 20 and 50 μg·kg^-1 of rGSTA3 protein-administered groups, E and F vessels appeared to be normal and improved on day 6 and 15. Furthermore, qRT-PCR results showed that rGSTA3 protein significantly (P < .05) up-regulated the expression of the most important angiogenesis-related integrin family genes ITGA2, ITGA5, ITGB2, ITGB3, ITGAV. The expression level of other genes including TBXA2R, FYN, IQGAP2, IL1R1, GIT1, RAP1B, RPL17, RAC2, MAML3, PTPN11, VAV1, PTCH1, NCOR2, CLU and ITGB3 up-regulated on dosage of rGSTA3 protein. In conclusion, angiogenesis is destroyed in thiram induced TD broilers, and rGSTA3 protein injection improved the vascularization of GPs by upregulating the angiogenesis related genes most importantly integrin family genes ITGAV, ITGA2, ITGB2, ITGB3, ITGA5.

Interactive effects of dietary vitamin K3 and Bacillus subtilis PB6 on the growth performance and tibia quality of broiler chickens with sex separate rearing

Both vitamin K and probiotics can promote the bone health of poultry and mammals. The present study was conducted to investigate the interactive effects between vitamin K3 (VK3) and Bacillus subtilis PB6 on the growth performance and tibia quality of broiler chickens with sex separate rearing. In a 3 × 2 × 2 factorial arrangement, 720 one-day-old broiler chicks (Arbor Acres) were assigned to 12 groups with three levels of dietary VK3 (0, 0.5 and 4.0 mg/kg), with or without probiotic supplementation (500 g/t) and with sex separation (male and female). Each group included 3 replicates with 20 birds per replicate. During day 1 to 21, 0.5 and 4.0 mg/kg of VK3 increased average daily gain (ADG) of all birds and average daily feed intake of male birds (P < 0.05). During day 22 to 42, probiotic supplementation increased the ADG of birds (P < 0.05). Probiotic addition increased the weight, length, diameter and strength of tibia in all birds, and 0.5 and 4.0 mg/kg of VK3 increased the tibial breaking strength of male birds at day 21 (P < 0.05). Vitamin K3 and probiotic synergistically increased tibial breaking strength at day 42 and ash content at day 21 (P < 0.05). Three factors exhibited interactive effects on the chemical composition of tibia at day 42, and female birds fed 4 mg/kg of VK3 and probiotic had the highest contents of ash, calcium and phosphorus (P < 0.05). Bacillus subtilis PB6 increased the serum phosphorus level of male birds at day 21 and serum calcium level of female ones at day 42 (P < 0.05). At day 21, in the probiotic-supplemented birds, serum osteocalcin (OCN) and bone-specific alkaline phosphatase (BALP) were increased by 0 and 4.0 mg/kg of VK3, respectively (P < 0.05). Probiotic increased serum OCN and cooperated with VK3 to increase the serum BALP at day 42 (P < 0.05). Vitamin K3 and probiotic synergistically down-regulated the mRNA expression of Runt-related transcription factor 2 and OCN at day 21 (P < 0.05). Vitamin K3 down-regulated the alkaline phosphatase (liver/bone/kidney) expression in male birds at day 21 and 42, but probiotic up-regulated the expression of these genes at day 42 (P < 0.05). In conclusion, VK3 and B. subtilis PB6 promoted the growth performance of broilers during starter and grower phases, respectively. They synergistically improved the physical and chemical traits of tibias, especially in grower phase, by modulating calcium and phosphorus metabolism as well as osteogenic gene expression.

Transcriptome-based screening of intracellular pathways and angiogenesis related genes at different stages of thiram induced tibial lesions in broiler chickens

Background

The Tibial dyschondroplasia (TD) in fast-growing chickens is mainly caused by improper blood circulation. The exact mechanism underlying angiogenesis and vascularization in tibial growth plate of broiler chickens remains unclear. Therefore, this research attempts to study genes involved in the regulation of angiogenesis in chicken red blood cells. Twenty-four broiler chickens were allotted into a control and thiram (Tetramethyl thiuram disulfide) group. Blood samples were collected on day 2, 6 (8- and 14-days old chickens) and 15 (23 days old chickens).

Results

Histopathology and hematoxylin and eosin (H&E) results showed that angiogenesis decreased on the 6th day of the experiment but started to recover on the 15th day of the experiment. Immunohistochemistry (IHC) results confirmed the expressions of integrin alpha-v precursor (ITGAV) and clusterin precursor (CLU). Transcriptome sequencing analysis evaluated 293 differentially expressed genes (DEGs), of which 103 up-regulated genes and 190 down-regulated genes were enriched in the pathways of neuroactive ligand receptor interaction, mitogen-activated protein kinase (MAPK), ribosome, regulation of actin cytoskeleton, focal adhesion, natural killer cell mediated cytotoxicity and the notch signalling pathways. DEGs (n = 20) related to angiogenesis of chicken erythrocytes in the enriched pathways were thromboxane A2 receptor (TBXA2R), interleukin-1 receptor type 1 precursor (IL1R1), ribosomal protein L17 (RPL17), integrin beta-3 precursor (ITGB3), ITGAV, integrin beta-2 precursor (ITGB2), ras-related C3 botulinum toxin substrate 2 (RAC2), integrin alpha-2 (ITGA2), IQ motif containing GTPase activating protein 2 (IQGAP2), ARF GTPase-activating protein (GIT1), proto-oncogene vav (VAV1), integrin alpha-IIb-like (ITGA5), ras-related protein Rap-1b precursor (RAP1B), tyrosine protein kinase Fyn-like (FYN), tyrosine-protein phosphatase non-receptor type 11 (PTPN11), protein patched homolog 1 (PTCH1), nuclear receptor corepressor 2 (NCOR2) and mastermind like protein 3 (MAML3) selected for further confirmation with qPCR. However, commonly DEGs were sarcoplasmic/endoplasmic reticulum calcium ATPase 3 (ATP2A3), ubiquitin-conjugating enzyme E2 R2 (UBE2R2), centriole cilia and spindle-associated protein (CCSAP), coagulation factor XIII A chain protein (F13A1), shroom 2 isoform X6 (SHROOM2), ras GTPase-activating protein 3 (RASA3) and CLU.

Conclusion

We have found potential therapeutic genes concerned to erythrocytes and blood regulation, which regulated the angiogenesis in thiram induced TD chickens. This study also revealed the potential functions of erythrocytes.

Graphical abstract

1. Tibial dyschondroplasia (TD) in chickens were more on day 6, which started recovering on day 15. 2. The enriched pathway observed in TD chickens on day 6 was ribosome pathway, on day 15 were regulation of actin cytoskeleton and focal adhesion pathway. 3. The genes involved in the ribosome pathways was ribosomal protein L17 (RPL17). regulation of actin cytoskeleton pathway were Ras-related C3 botulinum toxin substrate 2 (RAC2), Ras-related protein Rap-1b precursor (RAP1B), ARF GTPase-activating protein (GIT1), IQ motif containing GTPase activating protein 2 (IQGAP2), Integrin alpha-v precursor (ITGAV), Integrin alpha-2 (ITGA2), Integrin beta-2 precursor (ITGB2), Integrin beta-3 precursor (ITGB3), Integrin alpha-IIb-like (ITGA5). Focal adhesion Proto-oncogene vav (Vav-like), Tyrosine-protein kinase Fyn-like (FYN).

Plastrum Testudinis Extract Mitigates Thiram Toxicity in Broilers via Regulating PI3K/AKT Signaling

Tibial dyschondroplasia (TD) negatively affects broilers all over the world, in which the accretion of the growth plate (GP) develops into tibial proximal metaphysis. Plastrum testudinis extract (PTE) is renowned as a powerful antioxidant, anti-inflammatory, and bone healing agent. The current study was conducted to evaluate the efficacy of PTE for the treatment of thiram-induced TD chickens. Broilers (day old; n = 300) were raised for 3 days with normal feed. On the 4th day, three groups (n = 100 each) were sorted, namely, the control (normal diet), TD, and PTE groups (normal diet+ thiram 50 mg/kg). On the 7th day, thiram was stopped in the TD and PTE group, and the PTE group received a normal diet and PTE (30 mg/kg/day). Plastrum testudinis extract significantly restored (p < 0.05) the liver antioxidant enzymes, inflammatory cytokines, serum biochemicals, GP width, and tibia weight as compared to the TD group. The PTE administration significantly increased (p < 0.05) growth performance, vascularization, AKT (serine/threonine-protein kinase), and PI3K expressions and the number of hepatocytes and chondrocytes with intact nuclei were enhanced. In conclusion, PTE has the potential to heal TD lesions and act as an antioxidant and anti-inflammatory drug in chickens exposed to thiram via the upregulation of AKT and PI3K expressions.

Transcriptome analysis of MAPK signaling pathway and associated genes to angiogenesis in chicken erythrocytes on response to thiram-induced tibial lesions

This study was planned to investigate TD (Tibial dyschondroplasia) on the potential MAPK signaling pathway and angiogenesis related genes. Forty-eight broilers were allotted into control (C) and treatment (T) groups of 2, 6 and 15 days as C1, C2, C3, T1, T2 and T3. The histopathology results revealed that tibiotarsus bone of chickens had more lesions on day 6 (T2 group). The chondrocytes were disordered, and the size, shape and proliferation were affected. Transcriptome results revealed that differentially expressed genes (DEGs) identified were 63, 1026, 623, 130, 141 and 146 in C1 (2 days control vs 6 days control); C2 (2 days control vs 15 days control); C3 (6 days control vs 15 days control); T1 (2 days treatment vs 6 days treatment); T2 (2 days treatment vs 15 days treatment) and T3 (6 days treatment vs 15 days treatment) groups respectively. Whereas, 10 angiogenesis related-genes RHOC, MEIS2, BAIAP2, TGFBI, KLF2, CYR61, PTPN11, PLXNC1, HSPH1 and NRP2 were downregulated on day 6 in the treatment group. The pathway which was found enriched in the control and treatment groups was MAPK signaling pathway. Therefore selected 10 MAPK signaling pathway-related genes RAC2, MAP3K1, PRKCB, FLNB, IL1R1, PTPN7, RPS6KA, MAP3K6, GNA12 and HSPA8 which were found significantly downregulated in the treatment group on day 6. It is concluded that angiogenesis and MAPK signaling pathway related genes has an essential role in TD, as those top screened genes found downregulated in the thiram fed chickens when TD observed severed on day 6.

Identification of differentially expressed MiRNAs profile in a thiram-induced tibial dyschondroplasia

Tetramethyl thiuram disulfide (thiram) is a dithiocarbamate, which is widely used on seeds and storing food grains. The incorporation of thiram into the food chain could be a risk for both human beings and animals. Thiram-contaminated feed has been considered a common cause of tibial dyschondrolplasia (TD) in many avian species. The molecular mechanism of action of thiram on TD involving microRNA (miRNA) is not fully understood. For this purpose, the morbidity and pathologic changes were evaluated to understand the TD, and high-throughput RNA sequencing (RNA-Seq) was performed to explore the differentially expressed miRNAs (DEGs). RT-qPCR was used to confirm the validity as compared with sequencing data. The results showed that the marked alterations in the growth plate of the TD chickens were noticeable, with shrinking cells and irregular chondrocyte columns as compared with control group. In this study, we identified total 375 (p < 0.1), 340 (p < 0.05) and 266 (p < 0.01) significant DEGs between the TD and control groups. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of DEGs showed that the target miRNAs were significantly enriched in different treatment groups, such as apoptosis, mRNA surveillance pathway, mitophagy-animal, etc. This study provides theoretical basis for in-depth understanding the pathogenesis of thiram-induced TD and explore the new insights towards the proposed molecular mechanism of specific miRNA as biomarkers for effective gene diagnosis and treatment of TD in broilers.

Zinc source modulates intestinal inflammation and intestinal integrity of broiler chickens challenged with coccidia and Clostridium perfringens

Two dietary sources of zinc (ZnSO4 or organic Zn) were tested in chickens challenged with coccidiosis (Co) or coccidiosis plus Clostridium perfringens (CoCPF). On day 14, the chickens were orally gavaged with ∼5,000 Eimeria maxima sporulated oocysts. On day 19, 20, and 21 chickens challenged with C. perfringens were given a broth culture containing 108 cfu of this bacterium. Productive performance parameters were determined at d 14, 21, and 28. On day 21, necrotic enteritis (NE) lesions were scored, and intestinal permeability was evaluated. Jejunum and cecal tonsils were collected for morphology and gene expression analysis. On day 21, organic Zn improved BW gain by 18.6% (P = 0.07), and FCR by 12% (P = 0.09) in CoCPF challenged chickens vs. birds fed ZnSO4. From 1 to 28, organic Zn increased BW gain (P = 0.02), and improved FCR (P = 0.03) vs. birds fed ZnSO4. At 21 d, NE lesions were only observed in CoCPF birds (P < 0.001), and mortality due to NE was only observed when CoCPF birds were fed ZnSO4 (P = 0.001). Organic Zn fed birds had increased villus height in the jejunum (P = 0.005) and decreased intestinal permeability (P = 0.01) vs. ZnSO4. In the jejunum, organic Zn fed birds showed a downregulation of expression of IL-8 (P = 0.02), and upregulation of IL-10 (P = 0.05) in CoCPF birds vs. ZnSO4- CoCPF birds. As main effect, birds supplemented with organic Zn had higher mRNA expression of TLR-2 (P = 0.02) and IgA (P = 0.01). In the cecal tonsils, organic Zn fed birds showed upregulation of iNOS (P = 0.008) in CoCPF birds vs. ZnSO4-CoCPF birds. Organic Zn supplementation reduced intestinal permeability and attenuated intestinal inflammation of broilers co-challenged with coccidia and C. perfringens.

Ligustrazine recovers thiram-induced tibial dyschondroplasia in chickens: Involvement of new molecules modulating integrin beta 3

Tetramethyl thiuram disulfide (thiram) is a dithiocarbamate, which is extensively used in agriculture as pesticide and fungicide for treating grains intended for seed purposes and also for storing food grains. One of the most evident and detrimental effect produced by thiram is tibial dyschondroplasia (TD) in many avian species, by feeding diets containing thiram, a growth plate cartilage disease. TD is characterized by the lack of blood vessels and impaired vascular invasion of the hypertrophic chondrocyte resulting in the massive cell death. This study investigated the effects of ligustrazine on the treatment and control of thiram induced-TD. A total of 210 chicks were divided into three equal groups (n = 70): control group (received standard diet), TD group (feed on thiram containing diet from day 3-7), and ligustrazine group (feed on thiram containing diet from day 3-7 and after that ligustrazine @ 30 mg/kg from day 8 to day 18). During the experiment, the lameness, production parameters, tibia bone indicators, pathological index changes and integrin beta 3 (ITGB3) expressions were examined. The results reveal that ligustrazine plays an important role in improving angiogenesis and decreasing chondrocytes damage in TD chicks via a new molecule modulating ITGB3. So, the administration of ligustrazine can be an important way to cope with the losses and costs associated with TD in commercial poultry farming and animal welfare issue due to environmental contamination of thiram.

Clinical efficiency and safety of Hsp90 inhibitor Novobiocin in avian tibial dyschondroplasia

Tibial dyschondroplasia (TD) is a bone defect of broilers and other poultry birds that disturbs growth plate and it causes lameness. Previously we evaluated differential expression of multiple genes involved in growth plate angiogenesis and reported the safety and efficacious of medicinal plant root extracted for controlling TD. In this study, clinical and protective effect of an antibiotic Novobiocin (Hsp90 inhibitor) and expression of Hsp90 and proteoglycan aggrecan was examined. The chicks were divided into three groups; Control, thiram-induced TD, and Novobiocin injected TD. After the induction of TD, the Novobiocin was administered through intraperitoneal route to TD-affected birds until the end of the experiment. The expressions and localization of Hsp90 were evaluated by qRT-PCR, immunohistochemistry (IHC) and western blot, respectively. Morphological, histological examinations, and serum biomarker levels were evaluated to assess specificity and protective effects of Novobiocin. The results showed that TD causing retarded growth, enlarged growth plate, distended chondrocytes, irregular columns of cells, decreased antioxidant capacity, reduced protein levels of proteoglycan aggrecan, and upregulated in Hsp90 expression (p < 0.05) in dyschondroplastic birds as compared with control. Novobiocin treatment restored growth plate morphology, reducing width, stimulated chondrocyte differentiation, sprouting blood vessels, corrected oxidative imbalance, decreased Hsp90 expressions and increased aggrecan level. Novobiocin treatment controlled lameness and improved growth in broiler chicken induced by thiram. In conclusion, the accumulation of the cartilage and up-regulated Hsp90 are associated with TD pathogenesis and irregular chondrocyte morphology in TD is along with reduced aggrecan levels in the growth plate. Our results indicate that Novobiocin treatment has potential to reduce TD by controlling the expression of Hsp90 in addition to improve growth and hepatic toxicity in broiler chicken.

Effect of tetramethyl thiuram disulfide (thiram) in relation to tibial dyschondroplasia in chickens

Tetramethyl thiuram disulfide (thiram) is one of the important pesticides, which is extensively used in agriculture, but if it is combined with the cell membrane, then it causes membrane damage, bone morphogenic inactivation, and inhibited angiogenesis. Thiram has been considered a common cause of tibial dyschondrolplasia (TD) in various avian species, because it becomes the part of feed due to environmental contamination and its overuse in agriculture as pesticides or fungicide. However, there is no systematic study on the changes of the correlation indexes with toxic effect of the thiram in chickens. Therefore, we evaluated the toxic effects of thiram on growth performance of chickens, viscera organ index, pathological changes in tissue, and gene expression associated with osteoblast differentiation, vascularization, and tibial bone development. For this study, 1-day chickens (n = 300) were randomly distributed into two equal groups, control group (normal basal diet) and thiram group (adding thiram 40 mg/kg in basal diet). The result presented that thiram group chickens were looking unhealthy, lazy, and showing clinical symptoms like lameness. Thiram treatment significantly reduced the performance of chickens, liver index, and tibial length compared with control group. The toxic effect of thiram increased the visceral organ index (spleen and cardiac), tibia index, and TD severity considerably. It also increased serum Ca²⁺ and P³⁺ concentration and decreased tibial density compared to control chickens but the difference was not significant. Histopathology of tibia and liver showed that there were severe lesions due to toxic effect of thiram. Furthermore, HIF-1α and VEGF antibody localizations were increased and WNT4 localization was reduced significantly in immunohistochemical analysis. This systemic study of toxic effects of thiram in chicken concluded that thiram reduced the growth performance of chickens through decreasing liver index, whereas increasing kidney, cardiac, and spleen index, and induced TD by changing the expressions of VEGF, HIF-1α, and WNT4.

Icariin Ameliorate Thiram-Induced Tibial Dyschondroplasia via Regulation of WNT4 and VEGF Expression in Broiler Chickens

Tibial dyschondroplasia (TD) is main bone problem in fast growing poultry birds that effect proximal growth plate (GP) of tibia bone. TD is broadly defined as non-vascularized and non-mineralized, and enlarged GP with tibia bone deformation and lameness. Icariin (Epimedium sagittatum) is a traditional Chinese medicine, which is commonly practiced in the treatment of various bone diseases. Recently, many researcher reports about the beneficial effects of icariin in relation to various types of bone conditions but no report is available about promoting effect of icariin against TD. Therefore, current study was conducted to explore the ameliorating effect of icariin in thiram-induced TD chickens. A total of 180 broiler chicks were equally distributed in three groups; control, TD induced by thiram (50 mg/kg), and icariin group (treated with icariin @10 mg/kg). All groups were administered with normal standard diet ad libitum regularly until the end of experiment. The wingless-type member 4 (WNT4) and vascular endothelial growth factor (VEGF) genes and proteins expression were analyzed by quantitative real-time polymerase chain reaction and western blot analysis respectively. Tibial bone parameters, physiological changes in serum, antioxidant enzymes, and chicken growth performance were determined to assess advantage and protective effect of the medicine in broiler chicken. The expression of WNT4 was decreased while VEGF increased significantly (P < 0.05) in TD affected chicks. TD enhanced the GP, lameness, and irregular chondrocytes, while reduced the liver function, antioxidant enzymes in liver, and performance of chickens. Icariin treatment up-regulated WNT4 and down-regulated VEGF gene and protein expressions significantly (P < 0.05), restored the GP width, increased growth performance, corrected liver functions and antioxidant enzymes levels in liver, and mitigated the lameness in broiler chickens. In conclusion, icariin administration recovered GP size, normalized performance and prevented lameness significantly. Therefore, icariin treatments are encouraged to reduce the incidence of TD in broiler chickens.

Differential expression of extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) in avian tibial dyschondroplasia

Tibial dyschondroplasia (TD) is an avian bone disorder of different aetiologies that may be associated with lameness. The disorder is characterized by focal disruption of endochondral bone formation, with a lack of matrix proteolysis and an accumulation of non-mineralized avascular cartilage. The aim of this study was to determine the expression of extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) in normal, thiram-induced TD lesions and in the process of recovery from TD in broiler chickens. An extracellular matrix (ECM) degrading enzyme, matrix metalloproteinase-9 (MMP-9), was selected to investigate the effects of CD147 in the degradation of ECM. Gene expression was analysed by quantitative real-time polymerase chain reaction and protein levels by immunohistochemistry and western blotting. The birds were divided into three groups: thiram fed; recovery; and controls. Genes encoding CD147 and MMP-9 were down-regulated during the development of the disease, and were up-regulated during recovery. Western blotting also showed lower protein levels of CD147 in TD, which increased during the recovery phase associated with ECM degradation and growth plate repair. The findings of this study suggest that ECM has a crucial role in the occurrence of TD and that CD147 appears to play a pivotal role in matrix proteolysis in the chicken, similar to that in other species.

Screening of differentially expressed genes in the growth plate of broiler chickens with tibial dyschondroplasia by microarray analysis

Background

Tibial dyschondroplasia (TD) is a common skeletal disorder in broiler chickens. It is characterized by the presence of a non-vascularized and unmineralized cartilage in the growth plate. Previous studies have investigated differential expression of genes related to cartilage development during latter stages of TD. The aim of our study was to identify differentially expressed genes (DEGs) in the growth plate of broiler chickens, which were associated with early stage TD. We induced TD using tetramethylthiuram disulfide (thiram) for 1, 2, and 6 days and determined DEGs with chicken Affymetrix GeneChip assays. The identified DEGs were verified by quantitative polymerase chain reaction (qPCR) assays.

Results

We identified 1630 DEGs, with 82, 1385, and 429 exhibiting at least 2.0-fold changes (P < 0.05) at days 1, 2, and 6, respectively. These DEGs participate in a variety of biological processes, including cytokine production, oxidation reduction, and cell surface receptor linked signal transduction on day 1; lipid biosynthesis, regulation of growth, cell cycle, positive and negative gene regulation, transcription and transcription regulation, and anti-apoptosis on day 2; and regulation of cell proliferation, transcription, dephosphorylation, catabolism, proteolysis, and immune responses on day 6. The identified DEGs were associated with the following pathways: neuroactive ligand-receptor interaction on day 1; synthesis and degradation of ketone bodies, terpenoid backbone biosynthesis, ether lipid metabolism, JAK-STAT, GnRH signaling pathway, ubiquitin mediated proteolysis, TGF-β signaling, focal adhesion, and Wnt signaling on day 2; and arachidonic acid metabolism, mitogen-activated protein kinase (MAPK) signaling, JAK-STAT, insulin signaling, and glycolysis on day 6. We validated seven DEGs by qPCR.

Conclusions

Our findings demonstrate previously unrecognized changes in gene transcription associated with early stage TD. The DEGs we identified by microarray analysis will be used in future studies to clarify the molecular pathogenic mechanisms of TD. From these findings, potential pathways involved in early stage TD warrant further investigation.

Zymography methods for visualizing hydrolytic enzymes

Zymography is a technique for studying hydrolytic enzymes on the basis of substrate degradation. It is a powerful, but often misinterpreted, tool yielding information on potential hydrolytic activities, enzyme forms and the locations of active enzymes. In this Review, zymography techniques are compared in terms of advantages, limitations and interpretations. With in gel zymography, enzyme forms are visualized according to their molecular weights. Proteolytic activities are localized in tissue sections with in situ zymography. In vivo zymography can pinpoint proteolytic activity to sites in an intact organism. Future development of novel substrate probes and improvement in detection and imaging methods will increase the applicability of zymography for (reverse) degradomics studies.

Inflammation dampened by gelatinase A cleavage of monocyte chemoattractant protein-3

Tissue degradation by the matrix metalloproteinase gelatinase A is pivotal to inflammation and metastases. Recognizing the catalytic importance of substrate-binding exosites outside the catalytic domain, we screened for extracellular substrates using the gelatinase A hemopexin domain as bait in the yeast two-hybrid system. Monocyte chemoattractant protein-3 (MCP-3) was identified as a physiological substrate of gelatinase A. Cleaved MCP-3 binds to CC-chemokine receptors-1, -2, and -3, but no longer induces calcium fluxes or promotes chemotaxis, and instead acts as a general chemokine antagonist that dampens inflammation. This suggests that matrix metalloproteinases are both effectors and regulators of the inflammatory response.