Screening of Proliferation-Related Genes and Pathological Changes in Thiram-Induced Tibial Dyschondroplasia

Abstract

Aim and Background. Tibial dyschondroplasia (TD) is a tibiotarsal bone disorder of rapid growing poultry species. The complete pathogenicity of TD remains unknown; therefore, a study was conducted to screen possible role of proliferation-related gene expression in thiram-induced tibial TD chickens. Materials and Methods. Three hundred sixty ( $n=360$ ) broiler chickens were equally divided into control (C) and thiram (T) groups. Furthermore, the C and T groups were dividedinto 8-, 9-, 11-, and 13-day-old chickens. Results. Clinically, it was observed that broiler chickens of group T had abnormal posture, gait, and lameness, and histopathological results revealed dead and abnormal chondrocytes of T group on day 6. Real-time qPCR results showed that HDAC1, MTA1, H4, and PCNA genes were significantly expressed ( $P<0.05$ ). HDAC1 was upregulated on days 1, 2, 4, and 6 ( $P<0.01$ ); MTA1 was upregulated on days 1 and 2 ( $P<0.01$ ); H4 was upregulated on days 2 and 4 ( $P<0.01$ ), and PCNA was downregulated on days 1, 2, and 4 ( $P<0.01$ ). Furthermore, IHC results of HDAC1 protein were significantly ( $P<0.01$ ) expressed in proliferative zone of day 1 and hypertrophic zone of day 6. MTA1 protein was significantly ( $P<0.01$ ) expressed on days 1, 2, and 6 in all zones, except prehypertrophic zone of day 2. Conclusion. In conclusion, the mRNA expressions of HDAC1, MTA1, H4, and PCNA were differentially expressed in the chondrocytes of thiram-induced TD chickens. HDAC1 and MTA1 protein expression found involved and responsible in the abnormal chondrocytes’ proliferation of broiler chicken.