Ultrasound biomicroscopy for biomechanical characterization of healthy and injured triceps surae of rats

This work describes the use of ultrasound biomicroscopy (UBM) to follow up the degeneration–regeneration process after a laceration injury induced in the lateral gastrocnemius (LG) and soleus (SOL) muscles of rats. UBM (40 MHz) images were acquired and used for biomechanical characterization of muscular tissue, specifically using pennation angle (PA) and muscle thickness (MT). The animals were distributed in three groups: the variability group (VG; N=5), the gastrocnemius injured group (GG; N=6) and the soleus injured group (SG; N=5). VG rats were used to assess data variability and reliability (coefficients of variation of 9.37 and 3.97% for PA and MT, respectively). GG and SG rats were submitted to the injury protocol in the LG and SOL muscles of the right legs, respectively. UBM images of muscles of both legs were acquired at the following time points: before and after injury (immediately, 7, 14, 21 and 28 days). We observed an increase in PA for the non-injured leg 28 days after injury for both GG and SG rats (GG=10.68 to 16.53 deg and SG=9.65 to 14.06 deg; P<0.05). Additionally, MT presented a tendency to increase (GG=2.92 to 3.13 mm and SG=2.12 to 2.35 mm). Injured legs maintained pre-injury PA and MT values. It is suggested that a compensatory hypertrophic response due to the overload condition imposed to healthy leg. The results indicate that UBM allows qualitative and quantitative muscle differentiation among healthy and injured muscle at different stages after lesion.

An ultrasound and histomorphological analysis of experimental liver cirrhosis in rats

We investigated whether liver injury by dual exposure to ethanol and carbon tetrachloride (EtOH + CCl4) for 15 weeks would persist after hepatotoxic agents were removed (EtOH + CCl4/8wR). After 15 weeks of hepatic injury with ethanol (5.5%, m/v) and carbon tetrachloride (0.05, mL/kg, ip), 5 of 11 female Wistar rats were sacrificed. The other 6 rats were maintained for an additional 8 weeks without hepatotoxic agents. Ultrasonography showed increased liver echogenicity and dilation of portal vein caliber in both groups (EtOH + CCl4: 0.22 +/- 0.01 cm, P < 0.001; EtOH + CCl4/8wR: 0.21 +/- 0.02 cm, P < 0.01) vs control (0.16 +/- 0.02 cm). Histopathology showed regenerative nodules in both experimental groups. Histomorphometry revealed increased fibrosis content in both groups (EtOH + CCl4: 12.6 +/- 2.64%, P < 0.001; EtOH + CCl4/8wR: 10.4 +/- 1.36%, P < 0.05) vs control (2.2 +/- 1.21%). Collagen types I and III were increased in groups EtOH + CCl4 (collagen I: 2.5 +/- 1.3%, P < 0.01; collagen III: 1.3 +/- 0.2%, P < 0.05) and EtOH + CCl4/8wR (collagen I: 1.8 +/- 0.06%, P < 0.05; collagen III: 1.5 +/- 0.8%, P < 0.01) vs control (collagen I: 0.38 +/- 0.11%; collagen III: 0.25 +/- 0.06%). Tissue transglutaminase increased in both groups (EtOH + CCl4: 66.4 +/- 8%, P < 0.01; EtOH + CCl4/8wR: 58.8 +/- 21%, P < 0.01) vs control (7.9 +/- 0.8%). Cirrhosis caused by the association of CCl4-EtOH remained for at least 8 weeks after removal of these hepatotoxic agents. Ultrasound images can be a useful tool to evaluate advanced hepatic alterations.

Bone marrow cell transplant does not prevent or reverse murine liver cirrhosis

We tested the effect of bone marrow cell (BMC) transplantation in either preventing or reversing cirrhosis on an experimental model of chronic liver disease. Female Wistar rats were fed a liquid alcohol diet and received intraperitoneal injections of carbon tetrachloride (CCl4) over 15 weeks. Ten animals (cell-treated group) received five injections of BMCs during the cirrhosis induction protocol (on the 4th, 6th, 8th, 10th, and 12th weeks) and four animals received the cells after liver injury was established through tail vein. Nine animals (nontreated group) were submitted to the previously described protocols; however, they received vehicle injections. Analyses were performed to verify whether the infusion of cells was effective in preventing the development of cirrhosis in our model of induction, and if the cells could reverse cirrhosis once it was established. Hepatic architecture and fibrotic septa were analyzed in liver slices stained with hematoxilin & eosin and Sirius red, respectively. Fibrosis quantification was measured by Sirius red histomorphometry. Indirect immunofluorescence was performed to detect the amount of tissue transglutaminase 2. Blood analyses were performed to assess liver injury and function by the assessment of alanine aminotransferase and albumin. Ultrasound was performed to analyze the portal vein caliber and presence of ascitis. Cirrhosis features (regenerative nodules and fibrous septa) were observed in histopathology after 15 weeks of continuous hepatic injury in nontreated and cell-treated groups. Collagen content, immunofluorescence analysis, and biochemical and ultrasound parameters were similar in nontreated and cell-treated groups; however, both groups showed significant differences compared to a normal control group. Cell infusions with bone marrow-derived cells seem to be ineffective in improving morphofunctional parameters of the liver when applied to chronic cases either during or after establishment of the hepatic lesion.