engleski

The influence of calcitriol on expression of TGFb-isoformes in tissues of chickens

Calcitriol is an active metabolite of vitamin D, which has an inhibitory effect on the growth of cells, and the expression of different markers of cell differentiation. The part of those effects could be attributed to a regulation of transforming growth factor-beta (TGFb) expression. The aim of this study was to examine the influence of calcitriol on expression of different isoforms of TGFb in various tissues of chickens. The study was carried out on 20 cockerels (11 weeks old). Single high doses of 10 µg/kg body mass of calcitriol/vs. placebo were administered subcutaneously ; animals were euthanized after 24h and tissues were harvested. Total RNA was extracted and real-time reverse transcription PCR was performed using a TaqMan probes and primers specific for the TGFb2-, 3- and 4-isoformes. Beta actin was used as a reference gene and relative quantification of the PCR products was performed by using a comparative CT (ΔΔCT) method. Acute administration of calcitriol resulted in significantly decreased RNA expression for TGFb4 in liver and kidney and TGFb3 in liver (p<0.05). In opposite, the treatment with calcitriol resulted in significantly increased expression of TGFb4 RNA in red and white musculature (p<0.05 and p=0.06, respectively). In liver, TGFb3 had multiply higher expression than other two isoforms, while TGFb2 had the highest expression in red muscle that was highly variable. The results showed that different isoforms of TGFb have distinct pattern of expression in different tissues. Calcitriol has tissue specific influence on TGFb-4 expression ; it decreases TGFb3 expression only in liver and has no influence on expression of TGFb2 in muscles, liver or kidney.

Calcitriol; deficit; TGFb; qRT-PCR

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