Signalizacija gena za receptor vitamina D, enzim 1 alfa-hidroksilazu i RANTES u mliječnih krava s hipokalcemijom

The aim of the current study focused on screening the signal of the vitamin D receptor (VDR), 1-alpha-hydroxylase (1α-OHase) enzyme, and chemokine regulated on activation, normal T-cell expressed and secreted (RANTES) genes in dairy cows with hypocalcaemia. A sample of 120 dairy cows (20 dairy cows per herd) in the transition period was studied. Blood samples were drawn from the selected dairy cows for both biochemical and molecular analysis. In cows with subclinical and clinical hypocalcemia, there was a significant (P<0.05) down-regulation of both VDR and RANTES genes, whereas there was a significant (P<0.05) up-regulation of the 1α-OHase enzyme. Moreover, there was a significant (P<0.05) increase in the levels of glucose, parathyroid hormone (PTH), sodium (Na), and chloride (Cl). Furthermore, there was a significant (P<0.05) decrease in the levels of phosphorous and potassium (K). On the animal level, there was a significant association between the expression pattern of the VDR gene and the cows’ breed, the cows’ age, parity number, body condition score, and history of previous transition period disorders. The increase in both the expression of 1α-OHase enzyme and the level of each of PTH, glucose, Na, and Cl in the serum were significant risk factors for the decreased expression of the VDR gene. Likewise, the decrease in both the expression of the RANTES gene and the level of calcium (Ca) and phosphorous in the serum were significant risk factors for decreased expression of the VDR gene. This study revealed that the expression of VDR, 1α-OHase enzyme, and RANTES genes in the blood was greatly affected in dairy cows with hypocalcemia, indicating the need for an extra dose of vitamin D to maintain the normal level of Ca in the blood, especially during periods of high need. Hence, this study provides an insight into the role of vitamin D and its related enzymes in promoting the productivity of dairy cows, especially during the critical production periods.Cilj ovog istraživanja bio je nadzor genskog signala za receptor vitamina D (VDR), enzim 1-alfa-hidroksilazu (1 α-OHase) i kemokin (Regulated on Activation Normal T-cell Expressed and Secreted – RANTES) u mliječnih krava s hipokalcemijom. Uzorci za biokemijske i molekularne analize prikupljeni su od 120 mliječnih krava (20 krava po stadu), tijekom prijelaznog razdoblja. U krava s subkliničkom i kliničkom hipokalcemijom utvrđena je znakovita (P < 0,05) podregulacija gena VDR i RANTES, te znakovita (P < 0,05) nadregulacija enzima 1-α-Ohaza. Nadalje, u tih životinja došlo je do znakovitog (P < 0,05) povećanja razina glukoze, paratireoidnog hormona (PTH), natrija (Na) i klorida (Cl), te znakovitog (P < 0,05) smanjenja razina fosfora (P) i kalija (K). Uvažavajući različite osobine životinja utvrđena je znakovita povezanost između izražajnosti VDR gena i pasmine krava, dobi krava, redoslijeda teljenja, ocjene tjelesne kondicije te prethodnih poremećaja u prijelaznom razdoblju. Povećanje, s jedne strane ekspresije za enzim 1 α-OHase i s druge strane razine PTH, glukoze, Na i Cl u serumu, dovelo je do znakovitog rizika za smanjenu ekspresiju VDR gena. Isto tako, smanjenje ekspresije gena RANTES i razine kalcija (Ca) i fosfora (P) u serumu bili su značajni čimbenici rizika za smanjenu ekspresiju gena VDR. Ovo je istraživanje pokazalo da je na ekspresiju gena VDR, 1 α-Ohaza i RANTES u krvi mliječnih krava uvelike utjecala hipokalcemija, što upućuje na potrebu dodatne doze vitamina D kako bi se održala normalna razina Ca u krvi, osobito u zahtjevnim razdobljima visoke proizvodnje. Stoga ova studija daje uvid u ulogu vitamina D i s njim povezanih enzima u poboljšanju produktivnosti mliječnih krava, posebno u kritičnim razdobljima proizvodnje