This study attempted to probe the role of complement activation in promoting acute myocardial infarction (AMI) induced by coronary artery ligation (CAL) in rats. The surgical technique used in this study significantly reduced early mortality (95% survival rate) and also reduced the variation in infarct size (33+/-1.87%) at 32 h after surgery. Time course studies on the initiation of AMI at various time points were carried out using physiological, biochemical, histopathological and electron microscopical techniques. Serum markers and activities of lysosomal hydrolases were found to be significantly elevated at the 8th hour post ligation. Histological studies showed polymorphonuclear cells emigration and total coagulation necrosis. Transmission electron micrograph exhibited mild distortion of muscle fibres and mitochondrial rupture with disrupted cristae. Immunoblotting studies confirmed the presence of alpha2-macroglobulin which supported the inflammatory response at 8th h of post ligation. The initiation of the complement (C) activation was observed by the increase in the level of the soluble form of the membrane attack complex (sC5b-9) in serum and left ventricle. Immunoexpression studies confirmed the initiation of the terminal C activation as shown by the expression of C5, C6, C7, C8, C9 and sC5b-9 complex at the 8th h of AMI. This study conclusively demonstrated that initiation of the C activation was observed to be significant at the 8th h of AMI induced by CAL in rats.

The aim of this study was to evaluate the time course events of cellular damage during myocardial ischemia and reperfusion injury in rats and to find out a correlation between the structural alterations with respect to the biochemical changes. Cardiac biomarkers and lysosomal enzymes viz. cathepsin D, acid phosphatase and beta-glucuronidase and matrix metalloproteinases (MMPs) were evaluated at different time points, in response to ischemia-reperfusion induced oxidative stress in an isolated rat heart model perfused in Langendorff mode. Microscopically, changes in myocardial architecture, myofibrillar degradation, and collagen (COL) integrity were studied using hematoxylin-eosin, Masson's trichrome and toluidine blue staining techniques. A three-fold increase in the level of myoglobin was observed after 30 min of ischemia followed by 120 min of reperfusion as compared to 15 min ischemia, 120 min reperfusion. Similarly, a significant increase (P<0.05) in the levels of lipid peroxides and superoxide anion coupled with a decrease in enzymatic and nonenzymatic antioxidant levels were observed. A concomitant increase in the activity of cathepsin D (24.07+/-0.95) and a higher expression of MMPs after 120 min of reperfusion following 30 min ischemia were shown to correlate with the myocardial damage as shown by histopathology, suggesting that free radical induced activation of cathepsin D and MMPs could mediate early damage during myocardial ischemia and reperfusion.

In vivo models of myocardial infarction induced by coronary artery ligation (CAL) in rats usually suffer from high early mortality and a low rate of induction. This study investigated the time course initiation of chronic myocardial infarction (CMI) in albino rats and the possibility of reducing early mortality rate due to myocardial infarction by modification of the surgical technique. CAL was carried out by passing the suture through the epicardial layer around the midway of the left anterior descending coronary artery including a small area of the myocardium to avoid mechanical damage to the heart geometry. In addition, the role of endothelin-1 (ET-1) in rat heart with congestive heart failure was critically assessed. Time course initiation experiments were designed by sacrificing the animals at different time intervals and by carrying out physiological, biochemical, histopathological, electron microscopical and immunohistochemical studies. Specific markers of myocardial injury, viz. cardiac troponin-T (cTnT), high sensitivity C-reactive protein, lactate dehydrogenase and fibrinogen were measured at different time points. Serum marker enzymes and activities of lysosomal hydrolases were found to be elevated on the eighth day post-ligation. Histopathological studies demonstrated focal areas showing fibrovascular tissue containing fibroblasts, collagenous ground substance and numerous small capillaries replacing cardiac muscle fibers. Transmission electron micrographs exhibited mitochondrial changes of well-developed irreversible cardiac injury, viz. swelling, disorganization of cristae, appearance of mitochondrial amorphous matrix densities, significant distortion of muscle fibers and distinct disruption of the intercalated discs. Immunoblotting studies confirmed the presence of alpha 2-macroglobulin which supported the inflammatory response. The severity of the CMI was inferred by the measurement of the level of ET-1 in plasma and left ventricle which was significantly higher in the CMI rats than in the sham-operated rats. Immunohistochemical studies at different time intervals showed that there was a significant immunoexpression of ET-1 on the eighth day post-ligation. This study conclusively showed that ligation of left anterior descending artery minimized mortality and ET-1 was expressed during CMI.

No abstract

Background An effort was made to assess the effectiveness of dietary supplementation of Ulva lactuca (U. lactuca), a seaweed and Azolla individually and in combination on different physiological parameters of Aseel chicken. A total of 40 Aseel chicks of 8 weeks old were allocated into four groups, C1 (control), T1 (Azolla alone), T2 (seaweed alone) and T3 (seaweed plus Azolla). Aseel chicks in C1 were fed with formulated grower feed alone, birds in T1 had control diet with 5% Azolla, birds in T2 had control diet with 3% U. lactuca and birds in T3 had control diet admixtured with 5% of Azolla and 3% of U. lactuca. Parameters were recorded for a continuous period of 2 months in 15 days interval. Results The growth performance was found to be significant (P ≤ 0.05) during 30 days of feed trials and highly significant (P ≤ 0.01) during 45 and 60 days of treatment. Birds in T3 had a higher body weight gain, shank length and feed conversion efficiency followed with T1 and T2 compared to C1. PCV, RBC, WBC and heterophil counts were not influenced (P ≥ 0.05) by dietary treatments. Uric acid, creatinine, AST, glucose, triglycerides and magnesium levels revealed a high significant (P ≤ 0.01) variation, and cholesterol level showed significant (P ≤ 0.05) changes during 30th and 60th day of feed trials between the control and treatment groups. Total protein, globulin, phosphorus and electrolytes like Na, K and Cl levels were not significant (P ≥ 0.05) during 30th day and were highly significant (P ≤ 0.01) during the 60th day of the trial. Conclusions It could be noted that inclusion of U. lactuca and Azolla as feed supplement in grower chicken had a better body weight gain when given in combination (U. lactuca and Azolla) rather than supplemented with the sole entity. Based on the haematological and serum biochemical analysis, the supplementation of U. lactuca and Azolla at the levels included in this trial did not pose any threat to the physiological well-being of Aseel chicken.