The effect of trimetazidine in reducing the ischemia-reperfusion injury in rat epigastric skin flaps

Systematic review of pathologic markers in skin ischemia with and without reperfusion injury in microsurgical reconstruction: Biomarker alterations precede histological structure changes

BACKGROUND

Ischemia and ischemia-reperfusion injury contribute to partial or complete flap necrosis. Traditionally, skin histology has been used to evaluate morphological and structural changes, however histology does not detect early changes. We hypothesize that morphological and structural skin changes in response to ischemia and IRI occur late, and modification of gene and protein expression are the earliest changes in ischemia and IRI.

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Studies reporting skin histology or gene/protein expression changes following ischemia with or without reperfusion injury published between 2002 and 2022 were included. The primary outcomes were descriptive and semi-quantitative histological structural changes, leukocyte infiltration, edema, vessel density; secondary outcomes were quantitative gene and protein expression intensity (PCR and western blot). Model type, experimental intervention, ischemia method and duration, reperfusion duration, biopsy location and time point were collected.

RESULTS

One hundred and one articles were included. Hematoxylin and eosin (H&E) showed inflammatory infiltration in early responses (12-24 h), with structural modifications (3-14 days) and neovascularization (5-14 days) as delayed responses. Immunohistochemistry (IHC) identified angiogenesis (CD31, CD34), apoptosis (TUNEL, caspase-3, Bax/Bcl-2), and protein localization (NF-κB). Gene (PCR) and protein expression (western blot) detected inflammation and apoptosis; endoplasmic reticulum stress/oxidative stress and hypoxia; and neovascularization. The most common markers were TNF-α, IL-6 and IL-1β (inflammation), caspase-3 (apoptosis), VEGF (neovascularization), and HIF-1α (hypoxia).

CONCLUSION

There is no consensus or standard for reporting skin injury during ischemia and IRI. H&E histology is most frequently performed but is primarily descriptive and lacks sensitivity for early skin injury. Immunohistochemistry and gene/protein expression reveal immediate and quantitative cellular responses to skin ischemia and IRI. Future research is needed towards a universally-accepted skin injury scoring system.

Exploration of the Protective Mechanism of Bax Removal against Ischemia Reperfusion Injury of Skin Flap through the p38 Mitogen-Activated Protein Kinase Pathway

This research is aimed at exploring the influences of the Bax gene in the p38 mitogen-activated protein kinase (MAPK) pathway and its protective mechanism against ischemia-reperfusion injury (IRI) of skin flap. Forty male Sprague-Dawley (SD) rats were equally divided into the experimental group (Bax gene knockout rats) and control group. The dorsal flap model was prepared, and the survival rate of flap was observed after surgery. The rat flap tissue was cut and stained with hematoxylin-eosin (HE) and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The distribution characteristics of p38MAPK and Bax were detected to evaluate the protective mechanism of Bax gene knockout on IRI of skin flap. After surgery, the survival rate of flaps in the experimental group (82.32%, 70.28%) was significantly higher than that in the control group (57.64%, 46.14%) (P < 0.05). The results of HE staining showed that on the 1^st day after surgery, compared with those in the control group, the skin flaps of the rats in the experimental group were arranged more neatly. The results of TUNEL staining showed that compared with that of the control group, the tissue structure of the skin flap of the experimental group was normal and only a few apoptotic cells appeared. In addition, compared with that in the control group (7.14, 4.25, 3.48, 2.18/6.46, 7.12, 4.86, and 2.44), the expression of Bax and p38 MAPK in the experimental group (0.96, 0.81, 0.76, 0.55/1.63, 1.33, 1.01, and 0.56) significantly decreased (P < 0.05). In short, after the Bax gene was knocked out, injury of the flap after ischemia-reperfusion was considerably improved, which may play a protective role on the IRI of the flap by affecting the p38MAPK pathway.

The Effect of Ceruloplasmin Against Ischemia-Reperfusion Injury in Epigastric Island Flap in Rats

BACKGROUND

Flap surgery is frequently used in plastic surgery to close tissue defects. Ischemia-reperfusion (I/R) injury is a significant problem resulting in partial or total flap necrosis. This study aimed to investigate the effect of ceruloplasmin on I/R injury in epigastric island flaps in rats.

MATERIAL AND METHOD

A total of 32 male Sprague-Dawley rats were divided into four groups with eight rats in each group: The flap was not elevated in Group I; the flap was elevated without ischemia or any application in Group II, after the intraperitoneal saline and ceruloplasmin application the flaps were elevated and ischemia was created in group III-IV, respectively. Bilateral epigastric artery flap was elevated in all groups except Group I. After 6 h of ischemia, the flap was reperfused and inset. Samples were taken from the right and left side of the flap area in other groups at the postoperative 24th h for biochemical analysis (catalase and malondialdehyde-MDA) and the seventh postoperative day for histopathological analysis (Modified Verhofstad score and epidermal thicknesses), respectively. Image analysis for necrosis areas was performed on photos taken on the 7th d.

RESULTS

Catalase level was significantly higher in Group IV.(0.15 ± 0.04 U/mg protein) (P < 0.05) Necrosis area percentage(14.4% ± 3.3%),MDA(3.6 ± 0.9 nmol/mg protein), edema(3), necrosis(2.75), and polymorphonuclear leukocyte infiltration(2.87) scores were significantly higher in group III.(P < 0.05). Fibroblast proliferation, collagen density (0.25), vascular density (0.25) scores and epidermal thickness (15.68 µm,) was significantly lower in group III. (P < 0.05) CONCLUSIONS: Our study demonstrated that ceruloplasmin application before ischemia reduced I/R injury in epigastric island flaps in rats.

Ameliorating Effects of β-Glucan on Epigastric Artery Island Flap Ischemia-Reperfusion Injury

BACKGROUND

Ischemia-reperfusion injury has been one of the culprits of tissue injury and flap loss after island flap transpositions. Thus, significant research has been undertaken to study how to prevent or decrease the spread of ischemia-reperfusion injury. Preventive effects of β-glucan on ischemia-reperfusion injury in the kidney, lung, and small intestine have previously been reported. In this study, we present the ameliorating effects of β-glucan on ischemia-reperfusion injury using the epigastric artery island-flap in rats.

MATERIALS AND METHODS

Thirty Wistar-Albino rats were equally divided into three groups: sham, experimental model, and treatment groups. In the sham group, an island flap was elevated and sutured back to the original position without any ischemia. In the experimental model group, the same-sized flap was elevated and sutured back with 8 h of ischemia and consequent 12 h of reperfusion. In the treatment group, 50 mg per kilogram β-glucan was administered to the rats using an orogastric tube for 10 d before the experiment. The same-sized flap is elevated and sutured back to its original position with 8 h of ischemia and 12 h of consequent reperfusion in the treatment group. Tissue biopsies were taken on the first day of the experimental surgery. Tissue neutrophil aggregation and vascular responses were evaluated by histological examinations. Tissue oxidant and antioxidant enzyme levels are evaluated biochemically after tissue homogenization. Topographic follow-up and evaluation of the flaps were maintained, and photographs were taken on the first and seventh day of the experimental surgery.

RESULTS

Topographic flap survival was significantly better in the β-glucan administered group. The neutrophil number, malondialdehyde, and myeloperoxidase levels were significantly lower while glutathione peroxidase and superoxide dismutase levels were significantly higher in the β-glucan administered group respective to the experimental model group.

CONCLUSIONS

Based on the results of our study, we can conclude that β-glucan is protective against ischemia-reperfusion injury. Our study presents the first experimental evidence of such an effect on skin island flaps.

Effect of Pioglitazone on endoplasmic reticulum stress regarding in situ perfusion rat model

BACKGROUND

Ischemia-reperfusion injury (IRI) can cause insufficient microcirculation of the transplanted organ and results in a diminished and inferior graft survival rate.

OBJECTIVE

This study aimed to investigate the effect of different doses of an anti-diabetic drug, Pioglitazone (Pio), on endoplasmic reticulum stress and histopathological changes, using an in situ perfusion rat model.

METHODS

Sixty male Wistar rats were used and were divided into six groups, consisting of the control group, vehicle-treated group and four Pio-treated groups (10, 20, 30 and 40 mg/kg Pio was administered). The rats were perfused through vena cava and an outflow on the abdominal aorta occurred. Following the experiment, kidneys and livers were collected. The level of the endoplasmic reticulum stress markers (XBP1 and Caspase 12) was analyzed using Western blot and histopathological changes were evaluated.

RESULTS

Histopathological findings were correlated with the Western blot results and depict a protective effect corresponding to the elevated dosage of Pioglitazone regarding in situ perfusion rat model.

CONCLUSIONS

In our study, Pioglitazone can reduce the endoplasmic reticulum stress, and the most effective dosage proved to be the 40 mg/kg Pio referencing the kidney and liver samples.

Trimetazidine Attenuates Exhaustive Exercise-Induced Myocardial Injury in Rats via Regulation of the Nrf2/NF-κB Signaling Pathway

Exhausted exercise has been reported to cause the damage of myocardial structure and function in terms of cardiomyocyte apoptosis, oxidative stress, and energy metabolism disturbance. Trimetazidine (TMZ), as an anti-ischemic agent, has been approved to be effective in promoting myocardial energy metabolism, anti-inflammatory, and anti-oxidation. However, few studies examined the effects of TMZ on myocardial injury induced by exhausted exercise. To investigate whether TMZ could ameliorate the exhaustive exercise-induced myocardial injury and explore the underlying mechanisms, here the rat model of exhaustive exercise was induced by prolonged swimming exercise and TMZ was administrated to rats before exhaustive exercise. According to the results, we demonstrated that exhaustive exercise led to cardiomyocyte damage in rats as evidenced by elevations in cTnI and NT-proBNP levels, and decrease in CX43 expression, which was attenuated by TMZ treatment. Moreover, the administration of TMZ was found to restrain exhaustive exercise-induced oxidative stress damage by increasing GSH level, SOD and GSH-Px activities, and decreasing MDA level. Additionally, TMZ ameliorated myocardial injury by inhibiting apoptosis via reducing Bax/Bcl-2 ratio and down-regulating cleaved caspase-3, cleaved PARP, and cytochrome c levels in the myocardium of rats. Furthermore, we found that TMZ suppressed oxidative stress and cardiomyocyte apoptosis via activation of Nrf2/HO-1 and inactivation of NF-κB signaling pathways. Therefore, our study suggested that TMZ provided cardioprotection in rats after exhaustive exercise, indicating TMZ might served as a potential therapeutic drug for exhaustive exercise-induced myocardial injury.