Objective To study the expression of hypoxia inducible factor-1alpha (HIF-1α) mRNA in re-nal tissue after renal ischemia-reperfusion injury (IRI), and to investigate the effect of hyperbaric oxygen (HBO) on renal IRI and its mechanism. Methods Forty-two Wistar rats were randomly divided into a normal control group(n =6), a renal IRI group (n=18) and an HBO treatment group (n=18). Renal IRI models were established in all the rats. The plasma levels of Cr in the experimental groups were then measured after 1, 3 and 5 hours. The expres-sion of HIF-1α mRNA was also detected using real-time PCR and immunohistochemistry. Kidney tissue sections were preserved for ultrastructure examination. Results (1) The average levels of plasma Cr in the renal IRI group were significantly higher than those in the control group. Compared with the renal IRI group, plasma Cr was significantly lower in the HBO treatment group. (2) The average expression of HIF-1α mRNA was significantly lower an hour after reperfusion, but significantly higher after 3 hours than in the control group. There was no significant difference by the 5th hour after reperfusion. In the HBO treatment group, HIF-1α mRNA was up-regulated significantly at the 1st and 3rd hour after reperfusion compared with the renal IRI group, but it was reduced significantly by the 5th hour after reperfusion. (3) The severity of the kidney injury increased gradually with time in the renal IRI group. After HBO treatment, however, the damage to the renal tissues decreased significantly. Conclusions HIF-1α mRNA plays an important role in the development of renal IRI. The damage to renal tissues and renal function improves significantly after reperfusion and HBO treatment through earlier priming and up-regulating of HIF-1α mRNA expression. HBO should be applied early to help prevent renal IRI.

Objective:To develop and validate gas chromatographic methods for the determination of residual benzene in carbomer copolymer,carbomer homopolymer and carbomer interpolymer,to address the issues of the current method in the Chinese Pharmacopoeia in the actual detection process,such as low sensitivity and poor repeatability of benzene detection in the mixed reference solution,and to optimize and improve the current stand-ards for series of carbomer pharmaceutical excipients.Methods:Samples were separated on a column DB-624(30 m ×0.530 mm,3.00 μm)with temperature programming,the inlet temperature of 140 ℃,the detector tem-perature of 250 ℃,and the split ratio of 5∶1.The external standard method was adopted for the quantitative deter-mination of residual benzene.Results:The linearity was great across the range of 0.04-1.00 μg·mL-1(r=0.996 8),the injection precision of benzene was 6.8％(n=6),and the average recovery rate was 96.89％(RSD=8.1％,n=9).Conclusion:The gas chromatographic method established in this research is more specif-ic,with higher accuracy and precision compared to the current method in the Chinese Pharmacopoeia.This optimized method is more suitable for the determination of residual benzene content in carbomer copolymer,car-bomer homopolymer and carbomer interpolymer,providing reference and guidance for the quality management and the control of carbomer.