Ultrasonographic findings of the mammary gland, liver, gallbladder, spleen, and kidneys in transgenic goats for hG-CSF during induced lactation

Abstract

In transgenic murine models, the study of certain organs or tissues can be performed after euthanasia of some specimens. However, this practice may not be economically feasible when applied to livestock such as transgenic goats. It is necessary to use minimally invasive methods to perform in vivo studies of organs that may be affected by disorders related to the activity of the transgene, particularly during milk production, when the recombinant protein is secreted. The aim of this study was to describe ultrasonographic findings of the liver, gallbladder, spleen, kidneys, and mammary glands in transgenic goats for evaluating the effect of human granulocyte-colony stimulating factor (hG-CSF) expression in milk during induced lactation. Six female Canindé goats-three transgenic (T) and three non-transgenic (NT)-were subjected to hormone therapy to induce lactation; ultrasonographic examinations of the liver, gallbladder, spleen, kidneys, and mammary gland were performed during both the hormonal therapy and the lactation period at different intervals depending on the organ being examined. On Day 16 (Day 1 = hormonal therapy initiation), all goats were lactating and presented healthy mammary glands, characterized by echogenic parenchyma showing a granular echotexture. Transgenic and non-transgenic goats were compared on the basis of measurements and ultrasound images obtained from each organ. No differences between T and NT animals were observed in the examined area for the liver, gallbladder, spleen, and kidneys. Liver and renal echogenicity and appearance of gallbladder and portal and hepatic veins were similar in all females. Ultrasonographic findings of the mammary gland, liver, gallbladder, spleen, and kidneys in transgenic goats did not show any difference from those in non-transgenic goats.Thus, these results suggest that the presence and expression of the transgene had no effect on the ultrasonographic findings of mammary gland and abdominal organs in the transgenic goats. Moreover, the findings shows that ultrasonography is a useful screening tool for clinical examination of transgenic goats; this allows the investigation of possible disorders and avoids the unnecessary use of invasive techniques.