Relationship between plasma AVP concentration changes and myocardial collagen content in aging rats with pneumonia

    LI Yanª²Chuan1£¬ ZHAO Lianª²You1, WANG Shiª²Wen2, ZHENG Qiangª²Sun1, XUE Yuª²Sheng1, LI Aiª²Guo1, CHEN Yongª²Qing1

    1Department of Cardiovasology, Tangdu Hospital, Fourth Military Medical University, Xi¬ðan 710038£¬China, 2Institue of Geratic Cardiology, PLA General Hospital, Beijing 100853, China

    ¡¾Abstract¡¿ AIM: To investigate the relationship of changes in plasma Arginine vasopressin (AVP) concentration to myocardial collagen content in experimental aging rats with pneumonia. METHODS: Male Spragueª²Dawley rats (n=35), subcutaneously injected with 150 mg Dª²galactose/kg body weight daily for 40 days to establish the model of experimental aging rats, were randomly divided into 3 groups. The model group (n=12) and the antibiotic group (n=11) received intratracheal injection of pneumococcus 0.2 mL per animal to establish the pneumonia model. Control group (n=12) received intrabronchial instillation of an equivalent amount of normal saline. From the third day following the operation, additional intravenous penicillin was given to the antibiotic group for 13 days. Rat heart was taken out to evaluate the collagen content at day 15 after the operation by spectrophotometry technique. Plasma was used to determine the AVP concentration by radioimmunoassay technique. RESULTS: ¢Ù The plasma AVP concentration of the model group [(0.78¡À0.17) ¦Ìg/L] was statistically higher than that of the control group [(0.59¡À0.08) ¦Ìg/L] and the antibiotic group [(0.55¡À0.09) ¦Ìg/L] (both P<0.01). There was no statistical difference in the plasma AVP concentration between the antibiotic group and the control group (P>0.05). ¢Ú The myocardial collagen content of the model group [(6.54¡À0.91) mg/g] was statistically higher than that of the control group [(4.77¡À0.98) mg/g] and the antibiotic group [(5.22¡À0.83) mg/g] (both P<0.01). There was no statistical difference in the myocardial collagen content between the antibiotic group and the control group (P>0.05). ¢Û The value of the myocardial collagen content increased gradually with the elevation of plasma AVP concentration in experimental aging rats with bacteria pneumonia. A positive correlation was found between the plasma AVP concentration and the myocardial collagen content (r£½0.855, P<0.01). CONCLUSION: Pneumonia can promote the plasma AVP concentration in experimental aging rats. AVP may be involved in stimulating the myocardial collagen synthesis in experimental aging rats with pneumonia. ......