Therapeutic Effects And Molecular Mechanism Study Of Curcumin And Emodin On Thiram-induced Tibial Dyschondroplasia

Tibial dyschondroplasia(TD)is a disease of fast growing poultry birds.A typical lesion of TD is found at the proximal end of tibiotarsal bone,which is characterized by a plug of avascular and nonmineralized nature.TD affected chicken show poor body condition,deformed tibial bones and difficulty in moving.This disease not only causes huge economic losses worldwide but also raises animal welfare concerns.1.Effect of curcumin on VEGF and Dlx5 in thiram-induced tibial dyschondroplasia Curcumin is a spice of yellow bright color,a polyphenol derived from plant of Zingiberaceae family known as Curcuma longa.Curcumin has been known to inhibit bone resorption by inhibiting osteoclastogenesis.It modulates several molecular targets,which actively take part in the regulation of bone remodeling.However,therapeutic effectiveness of curcumin has not yet been studied against TD.Therefore,this study was planned to examine the effects of curcumin on TD lesion,performance of broilers and tibial bone parameters.Serum liver enzymes(ALT,ALP and AST)and SOD,MDA and GSH-Px contents in the liver were analyzed to evaluate the antioxidant activity of curcumin.Moreover,the expression of vascular endothelial growth factor(VEGF)and Dlx5 genes were examined before and after the treatment.For this purpose,four hundred broiler birds were equally divided into 4 groups: control,TD,TDR(self-recovery)and CUR(curcumin).Control group was fed standard feed from day 1 to 18.TD group was fed standard feed from day 1 to 3 and thiram containing(50 mg/kg)feed from day 4 to 18.TDR group was fed standard feed from day 1 to 3 and thiram containing feed from day 4 to 7 to induce the disease and then standard feed from day 8 to 18 to check the ability of diseased chicken to cope with the toxic effects of thiram.CUR group was fed standard feed from day 1 to 3 and thiram-containing feed from day 4 to 7 and then standard feed from day 8 to 18 along with the administration of curcumin(200 mg/kg).Chickens were randomly picked and slaughtered by cervical dislocation on day 7,10,14 and 18 from each group to evaluate above mentioned parameters.RT-qPCR,immunohistochemistry and Western blot results showed that,VEGF was significantly(P<0.05)up-regulated,while Dlx5 was significantly(P<0.05)downregulated in the GP of TD affected chicken.Curcumin administration significantly down-regulated(P<0.05)the VEGF and up-regulated Dlx5.H&E stained slides of tibia showed the disorganized cell columns with dissolved nucleus in the TD affected chickens,while curcumin administration restored the normal structure of cells.ALT,AST and MDA were found to be increased and ALP,SOD and GSH-Px were decreased in TD affected chickens.These enzymes levels and tibial bones parameters were also found to be near to control values after the administration of curcumin.Overall,the body condition of birds in TDR group was better than TD group however,the difference was not much significant in other results with an exception in few parameters.2.Effect of emodin on ALP,PPAR? and type I collagen genes in thiram-induced tibial dyschondroplasia Emodin is an anthraquinone derivative that is present in many extensively used natural medicinal herbs.It is being used for hundreds of years to treat various diseases including bone diseases and conditions.This experiment was planned to evaluate the therapeutic ability of emodin(80 mg/kg)against TD.The experimental design,parameters and techniques used in this study were similar to previous study as briefly described above.RT-qPCR,immunohistochemistry and Western blot results showed ALP was significantly(P<0.05)down-regulated in the chickens of TD group.Emodin administration significantly increased ALP level and up-regulated ALP in GP.PPAR? was found to be upregulated in TD.The activation of PPAR? increases bone resorption,however,it was found to be significantly down-regulated after the administration of emodin.Type I collagen levels are found to be almost similar in control and TD affected chickens,emodin up-regulated type I collagen.Mortality rate,tibial bone parameters like width,weight,length and width of GP in treatment group were found to be near to control group.Improved feed conversion ratio(FCR)and restored GP structures make emodin an effective drug against TD without posing a threat of ingestion of veterinary drug residues upon the consumption of treated birds.