[Effects of LPS-induced inflammation on differentiation of orbital pre-adipocytes in thyroid-associated ophthalmopathy].

OBJECTIVE

To investigate the effects of lipopolysaccharide (LPS)-induced inflammation on the differentiation of orbital pre-adipocytes in thyroid-associated ophthalmopathy (TAO) and to explore the mechanism of orbital adipose proliferation in TAO.

METHODS

Orbital adipose tissues were obtained from patients with TAO undergoing orbital decompression surgery. The orbital fibroblasts cultured from orbital adipose tissues were divided into group A and group B. In group A, orbital pre-adipocytes were incubated in culture medium containing 1 mg/L LPS for 8 hours before stimulated to differentiate into mature adipocytes with Differentiation Medium I and II. No LPS or other intervention was used in group B before induced to differentiate into mature adipocyte with Differentiation Medium I and II. Intracellular fat accumulation in differentiated adipocytes was determined by oil red O staining and the expression of cyclooxygenase2 (COX2) and peroxisome proliferators activated receptor γ (PPARγ) mRNA of both groups were detected by RT-PCR. Protein expression of COX2 and PPARγ in both groups was detected by Western-blot and the secretion of PGE(2) in the supernatant was detected by ELISA.

RESULTS

COX2 expression and secretion of PGE(2) in differentiated cells of both groups were significantly decreased compared with pre-differentiation (P < 0.05), while PPARγ mRNA and protein expression enhanced significantly (P < 0.05). COX2 mRNA and protein expression and secretion of PGE(2) of pre-differentiation cells in group A was significantly increased compared with group B (P < 0.05), while PPARγ mRNA and protein expression in group A was also stronger than those in the group B (P < 0.05). COX2 and PPARγ mRNA and protein expression and secretion of PGE(2) of differentiated cells in group A were greater than those in group B (P < 0.05).

CONCLUSION

LPS can induce inflammatory response of orbital preadipocytes in TAO and enhance the expression of COX2, PPARγ and PGE(2). The expression of PPARγ is enhanced significantly while the expression of COX2 and PGE(2) is attenuated markedly when the orbital pre-adipocytes differentiated into adipocytes.