Objective To investigate the protection effects of different pH N 2 hydroxyethyl piperazine N′ 2 ethanesulfonic acid (HEPES) Krebs Henseleit (KH) reperfusate solutions on immature myocardium and myocardial interstitium. Methods Isolated perfused Langendorff model from immature rabbit hearts were performed. Twenty four rabbits were divided into control group, ischemia reperfusion group and acidic reperfusate group. The left ventricular function recovery, myocardial water content(MWC), lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, malondialdehyde(MDA) and adenosine triphosphate (ATP) content, superoxide dismutase(SOD) activity , hydroxyproline(HP) and endothelin(ET) content were tested. Results The left ventricular functional recovery, ATP content, SOD activity and HP content in acidic reperfusate group were higher than those of ischemia reperfusion group( P lt;0.05).MWC, MDA content, CK and LDH leakage, and ET content in acidic reperfusate group were lower than those of ischemia reperfusion group( P lt;0.05). Conclusion These results suggest pH paradox might be one of important mechanisms for immature myocardium and myocardial interstitium ischemia reperfusion injury,and acidic perfusate, at the beginning of reperfusion ,might attenuate pH paradox and ameliorate functional recovery in isolated perfused immature rabbit hearts.
ObjectiveTo detect the development of retinal neovascularization (NV) induced by metabolic acidosis in neonatal rats and investigate the relationship between the occurrence of NV and vascular endothelial growth factor (VEGF). MethodsA total of 425 newborn Sprague-Dawley rats in experimental group underwent tubal feeding of NH4Cl (535 mg/kg) with the concentration of (50 mg/ml) (twice per day) from the 2nd day after the birth for 6 days and followed by a period of recovery. Additional 150 neonatal rats were in the control group without the tubal feeding. The rats were executed at the 3rd, 5th, 8th, 10th, 13th, 20th day after birth respectively. The retinal vessels were evaluated through retinal stretched preparation andadenosine diphosphatase (ADPase) staining; VEGF in retina was detected by enzymelinked immunosorbent assay(ELISA).ResultsIn the experimental group, the incidence of retinal NV at the 3rd, 5th, 8th, 10th, 13th, 20th day after birth was 0%，9%，26%，55%，19%, and 0% respectively. At the 3rd day, the expression of VEGF protein was lower in experimental group ［（101.1±14.2 ）pg/mg］ than that in the control group ［（133.2±15.9） pg/mg］（P＝0.004）, while at the 8th day it was higher in experimental group［(98.4±19.2) pg/mg］than that in the control group［（78.1±8.7） pg/mg］（P=0.028). There was no significant difference between the two groups at the 5th, 10th, 13th, and 20th day (Pgt;0.05). ConclusionsMetabolic acidosis may induce NV by injuring the developing retinal vessels. Retinal NV induced by acidosis relates to VEGF. (Chin J Ocul Fundus Dis, 2005,21:296-299)