Development and distribution of connective tissue fibres in the thymus of prenatal Surti goats (Capra hircus)

The present study was conducted to elucidate the developmental changes in the thymic connective tissue framework of 42 healthy Surti goat foetuses at different stages of their development ranging from 38 to 140 days. The thymic tissue at the age of 38 days was surrounded by a thin layer of immature collagen fibres. As development progressed between 44 to 45 days, the mesenchymal tissue radiates from capsule and divided the thymic parenchyma into irregular shaped lobules. The thymus at the age of 59 days showed strands of connective tissue fibres arises from interlobular septa that penetrated the parenchyma of thymus and divided periphery of the lobules into small chambers which forms cortex part of thymus. These connective tissue strands reached up to corticomedullary junction, therefore medulla of lobules were not divided. The thymus shows an increased concentration of collagen fibres in capsule and septa from 64 to 140 days of gestation. The thymus also showed reticular fibres in capsule, septa and endothelium of developing blood vessels. The number and thickness of reticular fibres were increased both in cortex and medulla as age advancement; however, there number was more in medulla as compared to cortex. The association of reticular fibres with Hassall’s corpuscles was observed only from the age of 135 days onwards. The elastic fibres were not observed at any stage of development.