Abstract: Objective To investigate the mechanism of endoplasmic reticulum stress (ERS) - related apoptosis pathway in renal interstitial fibrosis in rats with unilateral ureteral obstruction (UUO). Methods 60 male Wistar rats aged 8 weeks were randomly divided into sham operation group and model group (n = 30). According to the time of day and night, under the condition of room temperature and stable humidity. The rats in the model group were treated with left ureteral ligation. The sham operation group was only treated with no ligation of the ureter, and the rats were sacrificed on the 3 day, the 7 day and the 14 day after operation. Observe the two groups of rats HE and Masson staining of renal pathological changes; fundus venous blood samples were collected and separated serum blood urea nitrogen and creatinine determination; detection of glucose regulated protein 78 (Western blot GRP78), endoplasmic reticulum derived transcription factor (CHOP) and apoptosis related protein cysteine aspartic proteinase 3 (caspase-3 the expression of caspase-12 and protein). Results compared with sham operation group, UUO model group, renal histopathology showed renal tubular dilatation and renal interstitial fibrosis with ureteral obstruction prolonged and progressive aggravation; the expression of UUO GRP78 in the model group, CHOP, Caspase-3, caspase-12 protein in 3D after operation were raised, with the obstruction time prolonged, the expression is more significant (p<0.01). Conclusion endoplasmic reticulum stress related protein marker of early UUO in rat renal interstitial fibrosis with expression change in the long time, ERS may lead to the occurrence of apoptosis, Caspase-3, ERS apoptosis pathway 12 mediated promote renal fibrosis development.

Key words: endoplasmic reticulum stress, renal interstitial fibrosis, glucose regulated protein 78, endoplasmic reticulum derived transcription factor, cysteine aspartic proteinase