Hepatic mitochondrial and lysosomal alterations in acute experimental pancreatitis with ethanolic coetiology in rats

Experimental acute pancreatitis induces mitochondrial dysfunction in rat pancreas, kidney and lungs but not in liver

BACKGROUND/AIMS

Excessive systemic inflammatory response syndrome during severe acute pancreatitis (AP) leads to multiple organ dysfunction syndrome, which is the main cause of death and may be associated with primary mitochondrial disturbances. The aim of our study was to evaluate the role of mitochondria during experimental AP in pancreas and vital organs like kidney, lungs and liver within the first 48 h.

METHODS

AP was induced in 39 male Wistar rats by intraductal application of sodium taurocholate (5%, 1.75 ml/kg). Animals were divided into groups reflecting the time from induction of the AP till collection of tissues (control and 1, 3, 6, 12, 24, 48 h). Mitochondria were isolated by differential centrifugation and mitochondrial respiration rates were measured oxygraphically.

RESULTS

(1) Mitochondria in pancreas are affected within the first 6 h after onset of AP, (2) kidney mitochondria are affected 24 h after onset of AP, (3) lungs mitochondria are affected within 48 h after onset of AP whereas (4) liver mitochondria remain well preserved within the first 48 h. Severe AP-induced decrease in the oxidative phosphorylation of pancreas, kidney and lungs mitochondria was more pronounced with Complex I-linked (glutamate/malate) than with Complex II-linked (succinate) substrates and was associated with inhibition of Complex I.

CONCLUSION

Our data show that the disturbances of mitochondrial energy metabolism in pancreas, kidney and lungs may play an important role in the development and progression of AP as a systemic disease.

Early organ-specific mitochondrial dysfunction of jejunum and lung found in rats with experimental acute pancreatitis

INTRODUCTION

Multiple organ dysfunction is the main cause of death in severe acute pancreatitis. Primary mitochondrial dysfunction plays a central role in the development and progression of organ failure in critical illness. The present study investigated mitochondrial function in seven tissues during early experimental acute pancreatitis.

METHODS

Twenty-eight male Wistar rats (463 ± 2 g; mean ± SEM) were studied. Group 1 (n= 8), saline control; Group 2 (n= 6), caerulein-induced mild acute pancreatitis; Group 3 (n= 7) sham surgical controls; and Group 4 (n= 7), taurocholate-induced severe acute pancreatitis. Animals were euthanased at 6 h from the induction of acute pancreatitis and mitochondrial function was assessed in the heart, lung, liver, kidney, pancreas, duodenum and jejunum by mitochondrial respirometry.

RESULTS

Significant early mitochondrial dysfunction was present in the pancreas, lung and jejunum in both models of acute pancreatitis, however, the Heart, liver, kidney and duodenal mitochondria were unaffected.

CONCLUSIONS

The present study provides the first description of early organ-selective mitochondrial dysfunction in the lung and jejunum during acute pancreatitis. Research is now needed to identify the underlying pathophysiology behind the organ selective mitochondrial dysfunction, and the potential benefits of early mitochondrial-specific therapies in acute pancreatitis.

Hepatic damage during acute pancreatitis in the rat

We studied the alterations in the metabolism of liver mitochondria in rats with acute pancreatitis. Male Wistar rats were allocated to a control group (group I) and to five other groups corresponding to 2, 4, 12, 24 and 48 h after the induction of acute pancreatitis by the injection of 5% sodium taurocholate into the pancreatic duct. Sham-operated animals were submitted to the same surgical steps except for the induction of acute pancreatitis. Mitochondrial oxidation and phosphorylation were measured polarographically by determining oxygen consumption without ADP (basal respiration, state 4) and in the presence of ADP (activated respiration, state 3). Serum amylase, transaminases (ALT and AST) and protein were also determined. Ascitic fluid, contents of amylase, trypsin and total protein were also determined and arterial blood pressure was measured in all groups. In ascitic fluid, trypsin and amylase increased reaching a maximum at 2 and 4 h, respectively. Serum amylase increased at 2 h reaching a maximum at 4 h. Serum transaminase levels increased at 12 and 24 h. After 2 h (and also 4 h) there was an increase in state 4 respiration (45.65 +/- 1.79 vs 28.96 +/- 1.50) and a decrease in respiration control rate (3.53 +/- 0.09 vs 4.45 +/- 0.08) and in the ADP/O ratio (1.77 +/- 0.02 vs 1.91 +/- 0.01) compared to controls (P < 0.05). These results indicate a disruption of mitochondrial function, which recovered after 12 h. In the 48-h groups there was mitochondrial damage similar to that occurring in ischemic lesion. Beat-to-beat analysis (30 min) showed that arterial blood pressure remained normal up to 24 h (111 +/- 3 mmHg) while a significant decrease occurred in the 48-h group (91 +/- 4 mmHg). These data suggest biphasic damage in mitochondrial function in acute pancreatitis: an initial uncoupled phase, possibly secondary to enzyme activity, followed by a temporary recovery and then a late and final dysfunction, associated with arterial hypotension, possibly related to ischemic damage.