Primary cell culture of LHRH neurones from embryonic olfactory placode in the sheep (Ovis aries)

The aim of this study was to establish an in vitro model of ovine luteinizing hormone-releasing hormone (LHRH) neurones. Olfactory placodes from 26 day-old sheep embryos (E26) were used for explant culture, Cultures were maintained successfully up to 35 days, but were usually used at 17 days for immunocytochemistry, LHRH and neuronal markers such as neurofilament (NF) were detected by immunocytochemistry within and/or outside the explant. Three main types of LHRH positive cells are described: (1) neuroblastic LHRH and NF immunoreactive cells with round cell body and very short neurites found mainly within the explant, (2) migrating LHRH bipolar neurones with an fusiform cell body, found outside the explant, (3) network LHRH neuron, bipolar or multipolar with long neurites connecting other LHRH neurons, Cell morphology was very similar to that which has been described in the adult sheep brain. These results strongly suggest that LHRH neurones in the sheep originate from the olfactory placode. This model may represent a useful tool to study LHRH neurones directly in the sheep.