Histomorphometric study of the soleus muscle under conditions of modeling of spinal cord contusion injury: experimental morphological study

Objective. To conduct a morphometric analysis of the soleus muscle of rats after moderate spinal cord contusion injury.Material and Methods. Experiments were performed on female Wistar rats aged 8–12 months, weighing 270–320 g. Animals of the experimental group (n = 25) underwent laminectomy at the T9 level under general anesthesia and modeling of spinal contusion injury of moderate severity. Intact rats constituted the control group (n = 10). Euthanasia was performed on the 5th, 15th, 30th, 60th, 90th, and 180th days of the experiment. Paraffin sections were stained with hematoxylin-eosin and Masson, the diameters of muscle fibers were determined by computer morphometry, and histograms of their distribution were obtained.Results. In the soleus muscle, the signs of reversible reparative processes prevailed in response to neurotrophic damage. It was evidenced by a local increase in the diversity of myocyte diameters and the loss of polygonality of their profiles, focal destruction of muscle fibers, activation of the connective tissue component, disorganization of some intramuscular nerve conductors, and vascular fibrosis of perimysium. Nevertheless, the histostructure of an intact muscle prevailed in the course of the experiment, which was confirmed by the data of morphometric analysis. All histograms of the distribution of the muscle fiber diameters are unimodal with a mode in the range of 30–41 μm. On the 180th day, the maximum myocyte diameters in the histogram of the left limb muscle belonged to the range of 21–30 μm, which was typical for histograms in the intact group.Conclusion. The nature of the plastic reorganization of the soleus muscle when neurotrophic control is impaired indicates compensatory regeneration of muscle tissue by the type of restitution, which opens up the possibility of predicting the rehabilitation period. It is advisable to take this into account when developing medical and social programs and therapeutic measures, where the most important role is played by superficial neuromuscular and functional electrical stimulation.

Histomorphometric study of rat liver during the treatment of the acute toxic injury

Introduction. There are a few effective therapies are available for acute liver injury at present. The aim of the study was to investigate histological and morphometric changes in the liver using models of toxic damage caused by carbon tetrachloride (CCl4 ) and acetaminophen during correction with Oxymethyluracil (OMU). Material and methods. A total of ninety rats were divided into 18 groups. The treatment of acute liver damage models caused by a single injection of CCl4 or acetaminophen was carried out using “Heptor”, “Mexidol”, and OMU. The correction was carried out twice (sacrificed 24 hours after intoxication) and four times (sacrificed 72 hours after intoxication). Liver tissues were processed using standard histological techniques (H&E). A semi-quantitative assessment was performed using a scale based on the severity of liver cell deaths. Results. Twenty-four hours after administration of CCl4 or 72 hours after administration of acetaminophen, the treatment with OMU led to a decrease in liver cell death compared to the group with administration of only CCl4 or acetaminophen. Seventy-two hours after CCl4 and 24 hours after acetaminophen intoxication, these groups with the OMU treatment did not differ from those of the carbon tetrachloride- or acetaminophen-induced liver injury groups, respectively. Conclusion. Thus, on the model of CCl4 liver injury, the treatment with OMU is more effective for 24 hours. In the case of acetaminophen intoxication, the effectiveness of treatment with OMU is better for 72 hours. The results obtained are possibly associated with a different mechanism of the damaging effect of the studied toxicants.