[The effect of STAT1 antisense oligonucleotides on lung fibroblast proliferation and hydroxyproline secretion]

To investigate the effect of signal transducer and activator of transcription 1 (STAT1) antisense oligonucleotides on lung fibroblast proliferation and hydroxyproline secretion.

Ten adult female Wistar rats were randomly divided into two groups: one group was intratracheally instilled with bleomycin (BLM), while another group with 0.9% NaCl solution (NS). After 7 days, the rats were killed by right ventricle of heart exsanguinations under ketamine anaesthesia, and bronchoalveolar lavage (BAL) was performed to obtain alveolar macrophage (AM). AMs from the BLM group were divided into four groups, treated with STAT1 antisense oligonucleotides, STAT1 sense oligonucleotides, dexamethasone and medium alone (control), respectively. AMs and media were collected after culture for 36 h. The mRNA and protein expression of STAT1 and ICAM-1 in AMs were detected by RT-PCR and Cell-ELISA, respectively. The conditioned media were co-cultured with lung fibroblasts for 30 h, and then the cell proliferation and the concentration of hydroxyproline were examined.

(1) The STAT1 mRNA expression by AMs in the STAT1 antisense oligonucleotides group (31.8 +/- 3.5) was lower than those of AMs in the STAT1 sense oligonucleotides group (64.2 +/- 4.3), the dexamethasone group (44.1 +/- 4.6) and the control group (65.5 +/- 4.6) (P < 0.05). Moreover, the STAT1 mRNA expression by AMs in the dexamethasone group was also lower than those of AMs in the STAT1 sense oligonucleotides group and the control group (P < 0.05), but the STAT1 mRNA expression by AMs in the STAT1 sense oligonucleotides group was not different from that of the control group (P > 0.05). The STAT1 mRNA expression by AMs in the NS group (14.9 +/- 3.1) was lower than those of AMs in the STAT1 antisense oligonucleotides group, the STAT1 sense oligonucleotides group, the dexamethasone group and the control group (P < 0.05). (2) The mRNA expression of ICAM-1 showed similar changes to the STAT1 mRNA expression by AMs. (3) The STAT1 protein expression by AMs in the STAT1 antisense oligonucleotides group (4.4 +/- 0.6) or in the NS group (3.7 +/- 0.4) was lower than those of AMs in the STAT1 sense oligonucleotides group (7.7 +/- 0.7), the dexamethasone group (5.9 +/- 0.4) and the control group (7.6 +/- 0.6) (P < 0.05); and the STAT1 protein expression by AMs in the dexamethasone group was also lower than those of AMs in the STAT1 sense oligonucleotides group and the control group (P < 0.05), but the STAT1 protein expression by AMs in the STAT1 sense oligonucleotides group was not different from that of the control group (P > 0.05). (4) The changes of ICAM-1 protein expression, lung fibroblast proliferation and hydroxyproline concentration were consistent with the changes of STAT1 protein expression by AMs.

STAT1 antisense oligonucleotides could inhibit the mRNA and the protein expression of STAT1 and ICAM-1 in AMs. STAT1 antisense oligonucleotides also inhibited lung fibroblast proliferation and hydroxyproline secretion.