Effects Of Fluoride On Cultrued Human Ligamentum Flavum Cells And Related Research

Osisfication of the ligamentum flavum (OLF) of the thoracic spine is a special kind of ectopic ossification, and can be found frequently in spinal diseases. It may cause compression myelopathy, even paraplysis. The etiology of OLF still remains unclear, MRI and CT are effective examination in OLF, but too expensive. The un-operative treatments for OLF are often uneffetive, and laminectomy still is the main procedure hi treatment. The previous studies show that the main reasons for poor post-operation results of OLF patients are the delation in diagnosis and the needs of continued operation in OLF in spine. So how to find the high risk group of OLF all in good time and its' preventive treatment is the key to the study of the etiology of OLF.As we know, Bone growth factors play important roles in ectopic ossification. We immunochemically detected the expressions of BMP-2, TGF-pl and type I , II collagen in tissue samples of ligamentum flavum from OLF patients. The results showed that BMP-2 and TGF-pl were present in the uncalcified chondrocytes, and BMP-2 was also present in the fibroblast-like cells near cartilaginous area and in mesenchymal cells around new-born small vessels, which implied that BMP-2 play an important role in early process of OLF and TGF-pl in late process. In themeantime, the cytoplasm and extracellular matrix in the uncalcified chondrocytes were stained intensively for type I, II collagen, also implying that BMP-2 play an important role in OLF .Many reports shows there is a close relationship between fluorosis and ossification of the spinal ligaments, and also between degeneration and ossification of the spinal ligaments. Because of the limitations in study of fluoride effect on ossification of the spinal ligaments in vivo, the study in vitro is desperately needed and important. Such kinds of study has never been reported. Therefore we succesefully estibalished twenty-four cell lines obtained from ligamentum flavum from patients with OLF, lumbar stenosis and control. The characterization of these cultrued cells were analysised. Then we study the effects of fluoride on these cells. The results showed that the cultrued human ligamentum flavum cells could proliferate and be passed in vitro. Cells from OLF patients showed typical phenotype of osteoblast, while cells from patients with lumbar stenosis showed phonetypic characteristics for osteoblast in earlier process, and cells from control subjects with normal ligamentum flavum showed typical fibroblast phonetype. We also found that fluoride at high concentration could lead to cytotoxicity of the cultrued human ligamentum flavum cells in vitro, however, lower concentration resulted in significant increase of ALP activity and elevation of osteocalcin of most of cell lines from patients with lumbar stenosis, while made no effect on most of cell lines from patients with OLF and control subjects. The result suggested fluoride may cause OLF in vivo through stimulations of cells with earlier osteoblast-like phonetype into typical osteoblasts.During the study we also reproduced the model of fluorosis in rats by feeding with water of high concentration fluoride.The effects of fluoride on leading to degeneration and ossification of the ligamentum flavum in rat's lumbar spine were observeredIn conclusion, for the first time we conducted the experimental study of the effects of fluoride on cultrued human ligamentum flavum cells in vitro, and also degeneration and ossification of the ligamentum flavum in rat's lumbar spine caused by fluoride in vivo. The present study demonstrated the definite effect of fluoride on the ossification of ligamentum flavum in vivo and vitro, and indicated that continued research in clinics and experiments may be needed, in order to find a simple and effective method in early diagnosis, treatment and prevention of the OLF.