Effect of Melatonin on Casein Expression in Buffalo Mammary Epithelial Cells

The objectives of this study are to find out the effect of melatonin treatments (43 mu W & 430 mu M) on mRNA and protein expression of casein, and melatonin receptors in buffalo mammary epithelial cells (BuMEC) using reverse transcriptional polymerase chain reaction (qRT-PCR) and Western blotting. Furthermore, by using specific inhibitors against mTOR (Rapamycin) and Jak2-Stat5 pathway (AG490), effect of melatonin treatment on translational level of casein was measured. The results showed that melatonin treatment (430 mu M) significantly up-regulated casein level both at transcriptional (P<0.001) and translational (P<0.05) levels. Melatonin treatment significantly up-regulated mRNA expression of (P<0.05) melatonin receptor la (MT1) but melatonin receptor 1b (MT2) did not significantly varied. In the presence of mTOR inhibitor, rapamycin, melatonin failed to up regulate (P<0.05) protein expression of casein but no significant difference was found in the level of casein in the presence of Jak2-Stat5 inhibitor (AG490). These results indicate the significance of melatonin in altering milk casein expression in mammary epithelial cells in buffalo. Keeping in view the seasonality of buffalo in tropical and subtropical region, this study is important in the establishment of melatonin as the key modulator in changing concentration of casein in milk. (C) 2018 PVJ. All rights reserved