The influence of porcine cathelicidins on neutrophils isolated from rabbits in the course of bone graft implantation

[EN] Antimicrobial peptides are important elements of host defence because of their direct antimicrobial activity and modulatory role in innate immune response. The purpose of the study was to determine whether porcine peptides PR-39, protegrins (PGs) and low molecular weight extract (LMWE) are able to influence the neutrophil response during bone graft implantation in rabbits. The study was conducted on 10 White New Zealand rabbits and neutrophil activity was assayed on the basis of elastase, myeloperoxidase, and alkaline phosphatase release as well as free radical generation. Our study showed that PR-39 and PGs inhibited enzyme release from neutrophils except for elastase, which is essential in the first phase of injury. Superoxide and nitric oxide generation under the influence of PR-39 and PGs were also decreased. Moreover, we found that unlike separated peptides PR-39 and PGs, LMWE acts proinflammatorily, intensifying the neutrophil secretory response and free radical generation. These results should be taken into account in treatment with natural antimicrobial peptides. The increased neutrophil responses in the first phase of inflammation during surgery may be useful in prevention of infection, but LMWE should not be used in conditions in which excessive neutrophil response is injurious.Wessely-szponder, J.; Szponder, T.; Bobowiec, R.; Smolira, A. (2013). The influence of porcine cathelicidins on neutrophils isolated from rabbits in the course of bone graft implantation. World Rabbit Science. 21(3):175-183. doi:10.4995/wrs.2013.1350.SWORD17518321

SIGNIFICANCE OF STEM CELLS IN HEPATOCARCINOGENESIS IN RATS

Hepatic oval cells (OC) are considered to be the stem cells of the liver and have been linked to the development of hepatocellular carcinoma HCC, one of the most lethal cancers. The objective of this study was to analyse the proliferative response of OC obtained from rats receiving diethylnisamine DEN. In addition, we investigated the effects of resveratrol (Res) on the proliferation and oxidative markers of OC in vitro. OC isolated by in situ collagenase liver perfusion methods were treated with different concentrations of Res for 24, 48 and 72 hours. At the end of these periods the proliferative activity of OC, the release of superoxide anion by OC and the medium concentration of malonylodialdehyd were analyzed . The proliferation of OC cultured without Res increased from IP=0.945±0.02 to IP=1.525±0.031 after 24 and 72 hours respectively. A marked (p≤0.05) inhibition of OC proliferation was observed in the presence of 1.0 µM, 25 µM and 100 µM of Res. A significant decrease in the release of O2-. by OC, observed throughout the experimental period, was attributed to the presence of 25 µM of Res. Exposition of OC to 100 µM of Res inhibited the release of O2-. only after 48 and 72 hours of incubation. The presence of 25 µM of Res resulted in the depletion of MDA level, which did not exceed 0.19±0.009 nM. Proliferative activity of OC isolated from carcinogenic rats intensified throughout the culture period. When subjected to the carcinogenic effect of DEN, Res exerts anti-proliferative influence on OC. Moreover, our results provide evidence that Res attenuates oxidative stress during hepatocarcinogenesis

The response of bile secretion and ubiquinone Q10 to hyperglycaemia in sheep

The aim of these investigations was to establish the secretion of ubiquinone Q10 (UQ10) in bile of sheep under glucose-induced cholestasis. Experiments were performed on 9 cannulated sheep divided into three groups: I-infused with sodium taurocholate, II-with Na-taurocholate plus glucose, III-with Na-taurocholate and glucose plus propranolol, phentolamine and atropine. Infusion of glucose increased plasma glucose concentration from 3.89 +/- 0.593 mM/l to 12.69 +/- 0.852 mM/l in 90 min and produced elevation of plasma insulin from 124.68 +/- 1.984 to 839.54 +/- 29.212 pM/l. Employment of blocking agents reduced insulin release to maximum 685.71 +/- 50.087 pM/l in 90 min. Under infusion of Na-taurocholate, bile flow averaged 14.016 +/- 0.706 microl/min/kg b wt. In the second group, bile flow decreased to 7.08 +/- 0.59 microl/min/kg b wt. in 90 min, and reached 11.25 +/- 0.25 microl/min/kg b wt in 240 min. Addition of the blocking agents in the third group, resulted in a significant (p < 0.05) decrease in bile flow to 3.733 +/- 0.680 microl/min/kg b wt in 105 min. This reduction of bile flow occurred with significant (p < 0.05) reduction of bile acids secretion that averaged 0.032 +/- 0.087 mM/min/kg in the first hour after glucose infusion and was maintained to the end of the experiment. Marked (p < 0.05) increase in UQ10 secretion was observed in both experimental groups. Maximum values of UQ10 secretion were obtained during the second hour of the experiment and averaged 0.449 +/- 0.196ng/min/kg b wt in the second, and 0.338 +/- 0.184ng/min/kg b wt in the third group of animals. Because at the end of the experiment UQ10 secretion gradually decreased we have concluded that free radicals generated during cholestasis lead to reduction of endogenous antioxidant capacity