Effect of resistance training on osteopenic rat bones in neonatal streptozotocin-induced diabetes: Analysis of GLUT4 content and biochemical, biomechanical, densitometric, and microstructural evaluation

AIMS

To investigate the effect of resistance training-RT on glycemia, expression of the glucose transporter-GLUT4, bone mineral density-BMD, and microstructural and biomechanical properties of osteopenic rat bones in neonatal streptozotocin-induced diabetes.

MAIN METHODS

Sixty-four 5-day-old male rats were divided into two groups: control and diabetic rats injected with vehicle or streptozotocin, respectively. After 55 days, densitometric analysis-DA of the tibia was performed. These groups were subdivided into four subgroups: non-osteopenic control-CN, osteopenic control-OC, non-osteopenic diabetic-DM, and osteopenic diabetic-OD. The OC and OD groups were suspended by their tails for 21 days to promote osteopenia in the hindlimb; subsequently, a second DA was performed. The rats were subdivided into eight subgroups: sedentary control-SC, sedentary osteopenic control-SOC, exercised control-EC, exercised osteopenic control-EOC, sedentary diabetic-SD, sedentary osteopenic diabetic-SOD, exercised diabetic-ED, and exercised osteopenic diabetic-EOD. For RT, the rats climbed a ladder with weights secured to their tails for 12 weeks. After RT, a third DA was performed, and blood samples, muscles, and tibias were assessed to measure glycemia, insulinemia, GLUT4 content, bone maximum strength, fracture energy, extrinsic stiffness, BMD, cancellous bone area, trabecular number, and trabecular width.

KEY FINDINGS

After RT, glycemia, GLUT4 content, BMD, and bone microstructural and biomechanical properties were improved in diabetic rats (osteopenic and non-osteopenic). However, RT had no effect on these parameters in the EC and SC groups.

SIGNIFICANCE

These results suggest that RT improves GLUT4 content, BMD, and microstructural and biomechanical properties of bone in osteopenic and non-osteopenic diabetic rats and is effective in controlling glycemia.

The impact of burial period on compact bone microstructure: Histological analysis of matrix loss and cell integrity in human bones exhumed from tropical soil

Human bone histological analysis is a useful tool to assess post mortem diagenesis and to predict successful nuclear DNA typing of forensic material. This study is part of a series of studies developed by the authors intended to improve the understanding of post mortem diagenesis and to develop applications for DNA analysis of skeletal species from tropical soils, in order to optimize genetic and anthropological protocols. The aim of this study was to analyze the impact of burial period on the integrity of exhumed compact bone microstructure from tropical climate. In fragments of exhumed human femora from 39 individuals from the same cemetery (exhumed group) and 5 fresh femora from routine autopsies (control group), sections stained by hematoxylin-eosin were analyzed in order to measure bone microstructural integrity. We found that bone integrity index in exhumed group was negatively influenced by the period of burial (r = -0.37, p < 0.05) and highly significantly decreased (p < 0.0001) in comparison to control group. The period of burial and nitric acid decalcification time was positively correlated (r = 0.51; p < 0.01), leading to imply a bone petrification process during inhumation. Exhumed group showed higher level of matrix bone loss (p < 0.001), as expected, and 87% of cases analyzed were "tunneled" as described by Hackett. Bone integrity index and bone matrix tend to decrease in bones buried in tropical soil between 8-14 years of inhumation. This period is short if we consider cases in which there are preserved bones interred for longer periods in other environments. These data must be considered in cases where genetic identification of exhumed skeletons from tropical environment is required. The diagenesis in these bones and the variations of results found are discussed, clarifying some challenges for forensic laboratories, especially in DNA analysis.

Validation of an immunohistochemistry assay to detect turkey coronavirus: a rapid and simple screening tool for limited resource settings

The objective of the present study was to develop and apply the direct immunohistochemistry (D-IHC) assay to search for turkey coronavirus (TCoV) antigens in formalin-fixed embedded-paraffin tissues by the use of biotin-labeled polyclonal antibody. Twenty-eight-day-old embryonated turkey eggs (n = 50) were inoculated with TCoV-purified virus, and 3 d after inoculation, sections from ileum, ileum-cecal junction, and ceca were harvested, fixed in neutral formalin, and embedded in paraffin blocks and used as positive control. In addition, a total of 100 field samples from ileum, ileum-cecal junction, and ceca, collected from 30 to 45-d-old turkeys poults experiencing an outbreak of acute enteritis, were used to search for TCoV by the same D-IHC. All results were compared with those obtained by conventional RT-PCR and indirect fluorescent antibody assay (IFA) for all tested samples. Turkey coronavirus was detected in experimentally infected embryo tissues and also in field samples in 100% of ileum-cecal junction and ceca by the 3 detection procedures. With IFA as a reference assay, sensitivity and specificity of D-IHC were 98 and 58%, whereas sensitivity and specificity of reverse transcription-PCR were 96 and 66%, calculated from the total of tested samples from experimental infection. Each of the examined procedures was highly specific (D-IHC, 93%; RT-PCR, 90%), sensitive (D-IHC, 85%; RT-PCR, 86%), and agreement of both D-IHC and RT-PCR was 99 and 100%, respectively, compared with IFA results obtained from all the field samples. These findings demonstrated the utility of D-IHC for direct detection of TCoV from field samples and considering the sensitivity and specificity found here, can be used as an alternative technique.