Effects of TNF-α on changes of inducible nitric oxide synthase-nitric oxide system activity induced by arginine vasopressin in rat cardiac fibroblasts

AIM: To explore the effects of tumor necrosis factor-α (TNF-α) on inducible nitric oxide synthase (iNOS)-nitric oxide (NO) system activity in arginine vasopressin (AVP)-induced rat cardiac fibroblasts (CFs). METHODS: CFs were isolated by trypsin digestion method. Nitrate reductase method, spectrophotometry and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect NO contents, NOS activity and iNOS mRNA expression, respectively. RESULTS: AVP significantly increased iNOS mRNA expression, NOS activity and NO contents in CFs. Combined with AVP, TNF-α enhanced the effects of AVP on iNOS-NO system activity in a concentration-dependent manner. However, if the concentration of TNF-α was too high, the iNOS-NO system activity did not increase accordingly, but slightly decreased instead. CONCLUSION: TNF-α stimulates iNOS-NO system activity in coordination with AVP in CFs. The enhancement of NO contents inhibits ventricular remodeling induced by AVP and TNF-α. [