Objective: To observe the effect of acetazolamide (AZ) on the expressions of aquaporin 1 (AQP1) and AQP3 in fibroblast-like synoviocytes of rheumatoid arthritis (RAFLSs) and explore the roles of AQP1 and AQP3 in the development of rheumatoid arthritis (RA).
Methods: The study included 12 RA with knee hydrarthrosis and 10 osteoarthritis (OA) with knee hydrarthrosis and collected their synovia. From the synovia, FLSs were separated and cultured in vitro. RAFLSs were treated with different concentrations of acetazolamide (10(-4), 10(-6), 10(-8) mol/L) for different time (24, 48, 72 hours). The expressions of AQP1 mRNA and AQP3 mRNA in RAFLSs and OAFLSs were measured by RT-PCR; the expression of AQP1 protein was detected by immunofluorescence in RAFLSs and OAFLSs treated with the same concentration of acetazolamide (10(-4) mol/L) for different time (24, 48, 72 hours).
Results: AQP1 mRNA and AQP3 mRNA were both expressed in RAFLSs. The level of AQP1 mRNA in RAFLSs was significantly higher than that in OAFLSs (P<0.05). Different concentrations of acetazolamide (10(-4), 10(-6), 10(-8) mol/L) were able to significantly decrease the expression level of AQP1 mRNA in RAFLSs (P<0.05) in a time- and dose-dependent manner. There was no significant difference in transcription level of AQP3 mRNA between RAFLSs and OAFLSs (P>0.05); Immunofluorescence showed that AQP1 protein was significantly distributed on cell membrane. AQP1 protein expression was very apparent without acetazolamide treatment, whereas the expression was significantly attenuated by acetazolamide in a time-dependent manner.
Conclusion: Up-regulation of AQP1 expression in RA synovial membrane may be the one of mechanisms of arthroedema. Acetazolamide can reduce the expression of AQP1 rather than AQP3 in RAFLSs.