Time-related changes in hepatic and colonic mitochondrial oxygen consumption after abdominal infection in rats

Abstract

BackgroundEvidence suggests that early adaptive responses of hepatic mitochondria occur in experimentally induced sepsis. Little is known about both colonic mitochondrial function during abdominal infection and long-term changes in mitochondrial function under inflammatory conditions. We hypothesize that hepatic and colonic mitochondrial oxygen consumption changes time-dependently after sterile laparotomy and in the course of abdominal infection. The aim of the present study was to investigate the hepatic and colonic mitochondrial respiration after sterile laparotomy and abdominal infection over up to 96 h.MethodsAfter approval of the local Animal Care and Use Committee, 95 Wistar rats were randomized into 8 groups (n = 11–12): 1–4 sham (laparotomy only) and 5–8 colon ascendens stent peritonitis (CASP). Healthy, unoperated animals served as controls (n = 9). The mitochondrial respiration in colon and liver homogenates was assessed 24, 48, 72, and 96 h after surgery. Mitochondrial oxygen consumption was determined using a Clark-type electrode. State 2 (oxygen consumption in the presence of the substrates for complexes I and II) and state 3 respiration (ADP dependent) were assessed. The respiratory control ratio (RCR state 3/state 2) and ADP/O ratio (ADP added/oxygen consumed) were calculated for both complexes. Data are presented as means ± SD, two-way ANOVA followed by Tukey’s post hoc test.ResultsHepatic RCR was initially (after 24 h) elevated in both operated groups; after 48 h only, the septic group was elevated compared to controls. In CASP groups, the hepatic ADP/O ratio for complex I was elevated after 24 h (vs. controls) and after 48 h (vs. sham) but declined after 72 h (vs. controls). The ADP/O ratio for complex II stayed unchanged over the time period until 96 h.The colonic RCR and ADP/O did not change over time after sham or CASP operation.ConclusionHepatic, but not colonic, mitochondrial respiration is increased in the initial phase (until 48 h) and normalizes in the longer course of time (until 96 h) of abdominal infection.Electronic supplementary materialThe online version of this article (10.1186/s40635-018-0219-9) contains supplementary material, which is available to authorized users.

Sodium Thiosulfate Improves Intestinal and Hepatic Microcirculation Without Affecting Mitochondrial Function in Experimental Sepsis

“…Buprenorphine (0.05 mg • kg -1 s.c.) was applied at 8 h and 16 h after surgery. As described previously, animals were examined and scored every 6 h according to a defined protocol (Septic Rat Severity Score: SRSS) to determine the severity of sepsis and to monitor the animals with respect to their welfare (loss of body weight, appearance, spontaneous behavior, provoked behavior, breathing rate, expiratory breathing sound, abdominal palpation and condition of droppings) ( 22 , 23 ). Animals with unjustifiable suffering equivalent to a scoring of more than 10 points were euthanized.…”

“…Liver and colon homogenates were prepared as described previously ( 23 , 25 , 26 ). Briefly, liver tissue was placed in 4°C cold isolation buffer, minced into 2-3 mm 3 pieces, rinsed twice in isolation buffer to remove traces of blood and homogenized (Potter-Elvehjem, 5 strokes, 2000 rpm).…”

Indomethacin Increases the Efficacy of Oxygen Utilization of Colonic Mitochondria and Uncouples Hepatic Mitochondria in Tissue Homogenates From Healthy Rats

“…The maximal mitochondrial respiration (state 3) was recorded after the addition of ADP (250 μM for liver, 50 μM for colon). The concentrations of ADP were empirically adapted to the different tissue homogenates (hepatic and colonic tissue) in pilot experiments and as published previously ( 21 , 22 , 25 ). We used different concentrations of ADP for liver and colon since we identified these concentrations as non-saturated for the used amount of protein (4 mg/ml for the liver and 6 mg/ml for the colon).…”

Pravastatin and Gemfibrozil Modulate Differently Hepatic and Colonic Mitochondrial Respiration in Tissue Homogenates from Healthy Rats

“…Liver and colon homogenates were prepared as described previously [23,24,25]. Briefly, liver tissue was placed in 4 °C cold isolation buffer, minced into 2–3-mm 3 pieces, rinsed twice in isolation buffer to remove traces of blood, and homogenized (Potter-Elvehjem, Pro Scientific, Swedesboro, NJ, USA, 5 strokes, 2000 rpm).…”

“…Mitochondrial oxygen consumption was measured as described previously [23,24,25]. Briefly, the measurement was performed at 30 °C using a Clark-type electrode (model 782, Strathkelvin instruments, Glasgow, Scotland).…”