The coupling mechanism of connexin 43 and aquaporin 4 together inducing brain edema formation in glioma / 肿瘤

ABSTRACT

Objective: To search for the coupling mechanism of connexin 43 (CX43) and aquaporin 4 (AQP4) together inducing brain edema formation in glioma. Methods: Intracranial C6 glioma xenograft models were established in the rats, then magnetic resonance imaging detection was used to find the tumor and brain edema, and immunofluorescence and Western blotting method were used to detect CX43 and AQP4 expressions in both intratumoral and peritumoral tissues. C6 glioma cells and normal glial cells were cultured in hypotonic medium, then RT-PCR (reverse transcription-PCR) was used to detect and compare CX43 and AQP4 mRNA expression trends. AQP4 or CX43 expression was silenced in C6 glioma cells and normal glial cells by siRNA (small interference RNA) technology, then the other genetic change was detected by RT-PCR. Results: In C6 glioma xenograft models, CX43 expression was missed and AQP4 expression was slightly elevated in the intratumoral tissues. But in the peritumoral tissues, CX43 expression was slightly elevated and AQP4 expression was significantly increased. In vitro, the hypotonic environment induced elevation of AQP4 and CX43 mRNA levels with time-varying degrees in both normal glial cells and C6 glioma cells, but the change degree of normal glial cells was significantly lower than that of tumor cells, and the time window of CX43 changes was backward of AQP4. The elevated degree of CX43 was significantly decreased when AQP4 expression was silenced by siRNA in C6 cells (P 0.05). Conclusion: There are two different mechanisms of AQP4 and CX43 inducing brain edema formation intratumorally and in the edge of glioma. CX43 may be one of the potential downstream regulatory factors of AQP4. Copyright © 2013 by TUMOR.