TGF-β1 related inflammation in the posterior longitudinal ligament of cervical spondylotic myelopathy patients.

AIM

This study aimed to elucidate the pathogenesis of posterior longitudinal ligament (PLL) hypertrophy.

METHODS

Cervical PLL specimens were collected from CSM patients during surgery (n = 30) and during routine autopsy (n = 14), and processed for histological examination (HE staining and Masson's Trichrome staining) and IHC (CD3, CD68, CD31, TGF-β1 and collagen II). In addition, the mRNA expression of collagen I was detected in cervical PLL specimens from 16 CSM patients (n = 16) and from routine autopsy (n = 16) by RT-PCR.

RESULTS

Obvious fibrosis, cartilage metaplasia and calcification were found in the cervical PLL of CSM patients. In the degenerated PLL, CD68(+) macrophages were frequently identified, CD3(+) T lymphocytes were occasionally found, and many newly generated small vessels were also present. In the degenerated PLL, of the number of TGF-β1 positive cells increased markedly when compared with control group. IHC indicated TGF-β1 was secreted by macrophages. RT-PCR showed a significantly lower mRNA expression of collagen I in the PLL of CSM patients as compared to control group.

CONCLUSIONS

Macrophages are the major type of inflammatory cells involved in the cervical PLL degeneration, and TGF-β1 is related to the cervical PLL degeneration. TGF-β1 is mainly secreted by macrophages. Anti-inflammation may serve as an alternative non-surgical treatment and prophylactic strategy for PLL degeneration.