Bradykinin protects against DDP-induced GP-H1 cell damage via activation of PI3K/Akt/NO signaling pathway.

OBJECTIVE: To investigate the effect of bradykinin (BK) on cisplatin (DDP)-induced cardiotoxicity at the cellular level and its cytological mechanism. METHODS: The toxic effects of DDP on GP-H1 cells, and the effects of BK on DDP cardiomyocyte survival rate, DDP-induced malondialdehyde (MDA), lactate dehydrogenase (LDH), superoxide dismutase (SOD), reactive oxygen species (ROS), mitochondria membrane potential (MMP) and apoptosis were explored. RESULTS: DDP at different concentrations inhibited GP-H1 cells at 12 h after administration, and the inhibitory effect was more prominent at 24 h after administration and continued until 72 h after administration. The severity of GP-H1 cell damage induced by DDP was reduced by 0.1 µM, 1 µM, and 10 µM BK. After GP-H1 cells were treated with DDP, ROS levels increased and MMP levels decreased, while BK intervention inhibited these effects. At 24 h after DDP treatment, Bax/bcl-2 increased in GP-H1 cells, and the expressions of Caspase-3, p-NF-κB, p-p38 and p-Smad2 decreased. After intervention with BK, it was shown that Bax/Bcl-2 was significantly reduced, and the expressions of Caspase-3, p-NF-κB, p-p38 and p-Smad2 decreased. Bax/Bcl-2 and the expressions of Caspase-3, p-NF-κB, p-p38 and p-Smad2 of GP-H1 cells were basically not affected by BK alone. CONCLUSION: The protective effect of BK on DDP-induced GP-H1 cell damage in guinea pig is related to the activation of PI3K/Akt/NO signaling pathway by BK, which reduces oxidative stress levels in cardiomyocytes and also acts as an anti-apoptotic agent.

Efficient regeneration of mature castanopsis hystrix from in vitro stem explants.

Castanopsis hystrix is one of the main timber trees grown in China. However, severe shortage of natural seeds and the difficulty of explant regeneration has limited seedling supply. As such, there is a need for research on asexual multiplication of C. hystrix. This study established a rapid propagation technology system for C. hystrix genotypes, including explant treatment, proliferation, and rooting. HZ (a modified MS medium) supplemented with 4.4 µM BA and 0.5 µM IBA was found to be the optimal medium for shoot sprouting. The maximum proliferation coefficient and the number of effective shoots was obtained on HZ medium supplemented with 2.6 µM BA and 1.0 µM IBA, were 3.00 and 5.63, respectively. A rooting rate of 83.33% was achieved using half-strength HZ medium supplemented with 3.2 µM NAA. Adding vitamin C (80 mg⋅l-1) for 7 days in a dark environment reduced the browning rate, while increasing the proliferation rate. Additionally, through cytological observation, we established how and where adventitious roots occur. The survival rate of transplanted plantlets was > 90%. This is the first report of an in vitro regeneration technique that uses stem segments of mature C. hystrix as explants.