Effect of L-arginine on pulmonary surfactant and alveolar macrophages in rats with pulmonary injury induced by lipopolysaccharide / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effect of L-Arginine (L-Arg) on pulmonary surfactant (PS) expression and alveolar macrophage (AM) in rats with pulmonary injury induced by lipopolysaccharide (LPS).</p><p><b>METHODS</b>Model of acute lung injury (ALI) was made by injection (iv) with LPS 5 mg/kg in rats. Fourty-eight male SD rats were randomly divided into 3 groups(n = 16): control, model (LPS) and L-Arg groups. L-Arg (500 mg/kg ip ,L-Arg group) or saline (control and LPS group) was administrated at 3 h or 6 h after LPS injection respectively for 3 h. The expression of surfactant protein A (SP-A) mRNA in the lung tissue was detected by ISH. The total protein (TP) in the bronchoalveolar lavage fluid (BALF) was detected. Rat AM were isolated from the bronchial alveolar lavage fluid of SD rats and harvested by selective plating technique. LPS and L-Arg were added to the culture medium. The concentration of nitric oxide (NO),the activity of lactate dehydrogenase (LDH), the contents of tumor necrosis factor alpha (TNF-alpha) and interleukin- 6 (IL-6) in the culture supernatants were respectively measured.</p><p><b>RESULTS</b>Compared with the control group, the expression of SP-A mRNA was significantly decreased, the TP concentration was significantly increased in LPS group. Compared with LPS group at the same time points, treatment with L-Arg at 3 h after LPS, the expression of SP-A mRNA in lung tissue was increased markedly, whereas TP concentration was decreased significantly. In cultured rat AM, LDH activity, NO, TNF-alpha and IL-6 contents in culture medium were significantly increased in LPS group to compared with those of control group. LDH activity, TNF-alpha and IL-6 contents were decreased in L-Arg group compared with those of LPS group.</p><p><b>CONCLUSION</b>L-Arg can protect the lung against LPS-induced pulmonary injury by up-regulating the expression of PS and inhibiting inflammatory transmitters from AM.</p>

Effects of hydrogen sulfide on myocardial mitochondrial injury during acute myocardial ischemia in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effect of hydrogen sulfide (H2S) on mitochondrial function in acute myocardial ischemia in rats.</p><p><b>METHODS</b>Acute myocardial ischemia models were established by ligating the left anterior descending coronary artery (LADC) of rats. Fourty-eight male SD rats were randomly divided into 6 groups (n = 8): sham operation group, ischemia group, ischemia + sodium hydrosulfide (NaHS) low, middle and high dose groups and ischemia + DL-proparglycine(PPG) group. The ultrastructures of myocardial mitochondria were observed with electron microscope. The content of H2S in plasma and the activity of cystathionine-gamma-lyase (CSE) in myocardial tissue of rats were respectively detected. The swelling and activity of myocardial mitochondria were determined. The activities of ATPase, GSH-Px, SOD and the content of malondial-dehyde (MDA) in myocardial mitochondria of rats were also measured.</p><p><b>RESULTS</b>Compared with those of the sham operation group, the content of H2S in plasma, the activity of CSE in myocardial tissue and the activity of myocardium mitochondria were significantly decreased. The activities of ATPase, SOD, GSH-Px in myocardial mitochondria were significantly decreased, The content of malondial dehyde(MDA) in myocardial mitochondria and the swelling of mitochondria were distinctly increased in the ischemia group (P < 0.01). Compared with those of the ischemia group, the content of H2S in plasma and the activity of CSE in myocardial tissue were increased, and the activities of mitochondria, ATPase, SOD, and GSH-Px in myocardial mitochondria were significantly increased in ischemia + NaHS low, middle and high-dose groups; the swelling of mitochondria and the content of MDA in myocardial mitochondria were significantly decreased in ischemia + NaHS middle and high-dose groups (P < 0.05 or P < 0.01). The administration of PPG could partially reduce the myocardial protection of hydrogen sulfide (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>It could be concluded that the administration of hydrogen sulfide could enhance the activities of mitochondrial ATPase, SOD, GSH-Px, decrease the level of mitochondrial lipid peroxidation, and play a protective effect against acute myocardial ischemia.</p>