Heme oxygenase-1 alleviates ischemia/reperfusion injury in aged liver

AIM: To investigate if ischemia/reperfusion (I/R) injury in aged liver could be alleviated by heme oxygenase-1 (HO-1).METHODS: Three groups of SD rats (16 mo old) were studied. Group 1: control donors received physiological saline 24 h before their livers were harvested; group 2: donors were pretreated with hemih 24 h before their livers were harvested; and group 3: donors received hemin 24 h before their livers were harvested and zinc protoporphyrin (ZnPP,HO-1 inhibitor) was given to recipients at reperfusion. The harvested livers were stored in University of Wisconsin solution (4 ℃) for 6 h, and then transplanted to syngeneic rats. Serum glutamic oxaloacetic transaminase (SGOT),apoptotic cells, and apoptotic gene were measured 3, 6,12, 24, 48 h after reperfusion. We measured the apoptotic index by TUNEL, determined the expression of antiapoptotic Bcl-2 and proapoptotic (caspase-3) gene products by Western blot.RESULTS: After 3, 6, 12, 24, and 48 h of reperfusion, the SGOT levels (584.4±85.8 u/L, 999.2±125.2 u/L, 423.4±161.3u/L, 257.8±95.8 u/L, and 122.4±26.4 u/L) in hemin group were significantly (all P＜0.05) lower than those in saline group (1082.2±101.2 u/L, 1775.2±328.3 u/L, 840.4±137.8 u/L,448.6±74.3 u/L, and 306.2±49.3 u/L). Liver HO-1 enzymatic activity correlated with beneficial effects of hemin and deleterious effects of adjunctive ZnPP treatment. Markedly less apoptotic (TUNEL+) liver cells 3, 6, 12, 24, and 48 h after reperfusion (5.16±0.73, 10.2±0.67, 9.28±0.78, 7.14±1.12,and 4.78±0.65) (P＜0.05) could be detected in hemin liver grafts, as compared to controls (7.82±1.05, 15.94±1.82,11.67±1.59, 8.28±1.09, and 6.36±0.67). We detected the increased levels of Bcl-2 (1.5-fold) expression and compared with saline controls. These differences were most pronounced at 12 h after transplantation. In contrast, an active form of proapoptotic caspase-3 (p20) protein was found to be 2.9-fold lower at 24 h in hemin-pretreated group, as compared to saline liver transplant controls.CONCLUSION: HO-1 overexpression can provide potent protection against cold I/R injury. This effect depends, at least in part, on HO-1-mediated inhibition of antiapoptotic mechanism.

Study on genetic diversity and resource conservation of amphioxus (Branchiostoma balcheri Gray) population

Amphioxus is the ancestor of vertebrates 5×108 a ago, it is a typical transitional sample of evolution from invertebrates to vertebrates. Inter simple sequence repeats (ISSRs) and random amplified polymorphic DNAs (RAPDs) technologies were applied to detect the genetic variation of 3 bulking samples and individually sampled populations in nowadays Xiamen sea areas (Xiekou, Nanxian and Huangcuo) where the amphioxuses are alive. For the bulking sampled populations, 5 ISSR and 10 RAPD primers generated 357 bands, of which 181 (50.7%) were polymorphic. Nei index and UPGMA statistical analysis indicated that amphioxuses in these 3 areas could be divided into 2 groups. The genetic distance between animals in Nanxian and Huangcuo areas was 0.07 and classified into 1 group, while the population in Xiekou belonged to another group because its genetic distances in Nanxian and Huangcuo were 0.12 and 0.14, respectively. The result was in accordance with the morphological comparison among animals from those areas. For individually sampled population, Shannon's index of genetic diversity was used to partition the diversity of the animals among these 3 sea areas, and the results showed that the indices in populations of Xiekou, Nanxian and Huangcuo, were 0.583, 0.482 and 0.374, respectively. The linear regression equation analysis for amphioxus' genetic diversity versus the environment factors revealed that granularity/sorting coefficient and water depth were the most important factors that affect amphioxus genetic diversity. On the basis of the results, the suggestions for amphioxus resource conservation in Xiamen sea areas are put forward.