The Expression Of PEPT2 MRNA In The Lung Of Rats With Bleomycin-induced Pulmonary Fibrosis

Objective To investigate the expression of PEPT2 mRNA in the lung of rats with bleomycin-induced pulmonary fibrosis. Methods Fifty healthy adult Spragne -Dawley rats were divided into five groups , Rats of BLM 7 d,14 d,28 d groups were treated with a single instillation of 5mg/kg of bleomycin, to induced pulmonary fibrosis models. On days 7, 14 and 28 , the animals were killed by exsanguination respectly. Rats of NS group were treated by nomal saline, on days 14, the animals were killed by exsanguinations. Rats of control group were untreated .The lung samples were processed for light microscopy and determined the hydroxyproline concentration using the method of sample alkali hydrolization . The expression of PEPT2 mRNA were measured by RT-PCR, GAPDH was used as interna standard .The relative expression of PEPT2 mRNA each group was calculated by the GelDos system. PEPT2 cDNA fragments were tested by dideoxy chain termination. Results â‘ The morphological study showed that collagenous fiber proliferated on day 14 and 28 of BLM groups, especially on day 28, formed pulmonary fibrosis. â‘¡Compared with control group and NS group, hydroxyproline levels increased on day 7 of BLM group, but there was no statistical significient difference(P > 0.05). Hydroxyproline levels markly increased on days 14 and 28 of BLM groups, there was statistical significient difference (P < 0.05). The change of lung tissue pathology was coincident with the hydroxyproline levels. â‘¢There were no significient changes of pulmonary PEPT2 mRNA expression at different groups (P > 0.05). The PCR products were confirmed by direct sequencing that revealed identity with the published sequences. Conclusions â‘ The pulmonary fibrosis models of SD rats can be induced successly by a single instillation of 5mg/kg of bleomycin on 28d. â‘¡There were no significient changes of PEPT2 mRNA expression in the lung of rats with bleomycin-induced pulmonary fibrosis.