بررسي تشكيل هسته مركزي ديسك از نوتوكورد در موش صحرايي

A Study on Nucleus Pulposus Formation from Notochord in Rats

In order to study the development of notochord in the ratʹs intervertebral discs, 40 mature male and female rats were selected. The female rats were separated after coupling. At least two animals were used at each of the following ages: embryonic days 14,15,16,18 and 20, neonate rats aged 1,3,5 days and postnatal rats aged 2,3,4 and 6 weeks and also mature rats were selected. The intervertebral tissues were fixed in 10% formaldehyde, decalcified if necessary, and dehydrated in graded alcohol followed by embedding in paraffin. Serial 7 micrometer sections were cut and stained with H and E reticuline,toluidine blue trichrome maleory and were then examined by light microscopy. At E14, the notochord was uniform in diameter through both disc and vertebral body. By E15 notochordal cells were increased at the center of disc and by E16 expanded to form the nucleus pulposus. By E20 notochordal cells disappeared between adjacent discs. In 4-week rats, the extracellular matrix increased at the peripheral area of the nucleus pulposus. Intervertebral disc was fibrosed from the periphery to the center.