Arun Kumar Wahi

Protective Effect of L-arginine Against Necrosis and Apoptosis Induced by Experimental Ischemic and Reperfusion in Rat Liver

Background/Aim: To study the effect of L-arginine on apoptosis and necrosis induced by 1-h ischemia followed by 3-h reperfusion. Materials and Methods: Adult Wistar rats underwent 60 min of partial liver ischemia followed by 3-h reperfusion. Eighteen Wistar rats were divided into sham-operated control group (I) (n = 6), ischemia and reperfusion (I/R) group (0.9% saline (5 mL/kg, orally) for 7 days) (II) (n = 6), and L-arginine-treated group (10 mg/kg body weight daily orally for 7 days before inducing ischemia-reperfusion maneuver) (III) (n = 6). Apoptotic and necrotic hepatocytes, nitric oxide levels in hepatocytes, Bcl-2 mRNA, and Bcl-2 protein were measured. Liver injury was assessed by plasma alanine transaminases (ALT), aspartate transaminases (AST), liver histopathology, and electron microscopy. Results: An ischemic and reperfusion hepatocellular injury occurred as was indicated by increased serum ALT, AST, histopathology, and electron microscopy. Apoptosis and necrosis associated marker gene Bcl-2 mRNA and protein expression were decreased in I/R group. Pretreatment with L-arginine significantly decreased serum ALT and AST level and apoptotic and necrotic cells after 1 h ischemia followed by 3 h of reperfusion. Nitric oxide production in hepatocytes was increased twofold by L-arginine treatment when compared with I/R group. Histopathology and transmission electron microscopy (TEM) studies showed markedly diminished hepatocellular injury in L-arginine-pretreated rats during the hepatic I/R. Conclusion: Thus, it may be concluded that L-arginine afforded significant protection from necrosis and apoptosis in I/R injury by upregulated Bcl-2 gene and nitric oxide production.

CALCIUM ANTAGONIST PREVENTS CALCIUM FLUX INDUCED NECROSIS AND APOPTOSIS IN ISCHEMIC REPERFUSION OF RAT LIVER

Ca2+ accumulation in mitochondria is responsible for the cell abnormality associated with ischemia and reperfusion injury. The present study was aimed to evaluate the efficacy of Ca2+ channel blocker- amlodipine on the mitochondrial Ca2+ accumulation in ischemic and reperfusion (I/R) induced liver injury. Eighteen wistar rats were divided in sham-operated control group-I (n = 6), ischemia and reperfusion group-II (n = 6) and amlodipine treated group-III (1 mg/kg body weight /daily by oral route for 7 days before induced ischemia reperfusion manouver) (n = 6). Rats were subjected to 1h of hepatic ischemia followed by 3 h reperfusion. Mitochondrial Ca2+ content was measured and damage of mitochondria was confirmed by transmission electron microscopic examination. Bcl-2 gene expression was measured by reverse transcriptase polymerase chain reaction method. Pretreatment with Amlodipine effectively counteracted the alternation in mitochondrial Ca2+ content. TEM and expression of Bcl-2 protein confirms the restoration of cellular normalcy and accredits the cytoprotective role of Amlodipine against I/R induced hepatic injury. These findings showed that the mechanism of regulation of Bcl-2 gene expression by amlodipine may be the inhibitory action of Ca2+ entry into mitochondria and prevent apoptosis and necrosis.

Folic acid inhibits necrosis and apoptosis in ischemic and reperfusion induced injury in rat liver

Temporary clamping of the portal triad is a common strategy to minimize bleeding during liver transplantation. Increasing evidences suggests that oxygen derived free radicals and reintroduction of oxygen in ischemic tissue lead to ischemic and reperfusion injury (I/R) and lead to apoptosis and necrosis. Adult Wistar rat subjected to 60 min of partial liver ischemia followed by three hour reperfusion. Eighteen Wister rats were divided into sham-operated control group (I) (n = 6), ischemia and reperfusion group (II) (n = 6), folic acid treated group (1 mg/kg body weight/daily by oral route for 7 days before induced ischemia reperfusion maneuver) (III) (n = 6). Apoptotic and necrotic hepatocytes, mitochondrial antioxidant enzymes were measured. Liver injury was assessed by alanine transaminases (ALT), aspartate transaminases (AST), liver histopathology and electron microscopy. An ischemic and reperfusion hepatocellular injury was indicated by increased serum-ALT, AST, histopathology and electron microscopy studies. Apoptotic and necrotic cells were increased which was revealed by flow cytometry in I/R group. Pre- treatment with folic acid significantly decreased serum -ALT, AST levels, apoptotic and necrotic cells after 1 h ischemia followed by 3 h of reperfusion. Histopathology and TEM studies showed markedly diminished hepatocellular injury in folic acid pretreated rats during the hepatic I/R, which reached a level comparable to saline-treated rat of sham operated group. On the basis of our findings it may be concluded that folic acid afforded significant protection from necrosis and apoptosis in I/R injury.