Could skeletal muscle changes provide a reliable method for estimating the time since death: A histological, biochemical, and DNA study

Assessing the forensic implications of DNA degradation for PMI estimation using comet assay: A systematic review

Accurate post-mortem interval estimation is crucial in forensic investigations, providing essential information for criminal cases. Traditional techniques frequently encounter inaccuracies stemming from environmental and individual variables. The comet assay is a very sensitive technique that detects DNA damage, which has emerged as a promising tool for assessing DNA degradation. This approach can serve as a molecular clock for post-mortem interval estimation, offering a more precise and reliable means of determining the time since death in forensic cases. This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO-CRD42024554907) and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. An extensive electronic database search, including Google Scholar, Embase, Web of Science, PubMed, and Scopus was conducted to find the studies utilizing the comet assay for DNA degradation measurement in post-mortem interval estimation. Two reviewers independently screened and extracted data from eligible studies. The risk of bias tool from the Systematic Review Centre for Laboratory Animal Experimentation was used to evaluate the quality of the research. All six studies fulfilled the inclusion requirements, employing the comet assay on various animal tissues. Studies show a clear relationship between post-mortem interval and degradation of DNA, with varying rates depending on tissue type and environmental factors. The comet assay can detect DNA fragmentation effectively, but difficulties arise from variations in study designs and methodologies. Despite its promise for estimating post-mortem interval, the standardization of protocols is needed to improve reliability and applicability in forensics. Future research should establish standardized methods and explore environmental impacts on DNA degradation.

Postmortem interval estimation of time since death: impact of non-histone binding proteins, immunohistochemical, and histopathological changes in vivo

The postmortem interval (PMI) is one of the primary objectives and challenging tasks proposed for determining the time of death. This study aimed to estimate the PMI using serum levels of high mobility group box 1 (HMGB1), a biomarker of pyroptotic cell death, along with desmin immunohistochemical and histological analyses of the gastrocnemius muscle in rats at various time intervals. Serum and gastrocnemius muscle samples were collected at zero, 24-, 48-, 72-, and 96 hours postmortem from 50 rats maintained at 22 ± 2°C. The results revealed that the HMGB1 level peaked at 48 hours and dropped in a time-dependent manner afterward. Immunohistochemical analysis revealed a progressive decrease in desmin expression, with severe immunoreactivity (38.19%) at 0 hours, dropping to a minimal level (1.09%) 96 hours after death. Histological analysis of the gastrocnemius muscle at 96 hours revealed significant vacuolation, loss of normal architecture, reduced nuclear visibility, and complete autolysis of all myocytes. In conclusion, HMGB1 levels, desmin immunoreactivity, and histopathological alterations seen in the gastrocnemius muscle could be helpful, valuable, and potential markers for accurately determining PMIs in humans in future studies.

Thymoquinone Induces Nrf2 Mediated Adaptive Homeostasis: Implication for Mercuric Chloride-Induced Nephrotoxicity

BACKGROUND

the primary function of the kidney is to eliminate metabolic waste products and xenobiotics from the circulation. During this process, the kidney may become vulnerable to toxicity.

OBJECTIVE

it was aimed to investigate the impact of thymoquinone (TQ) in mercuric chloride (HgCl2)-induced nephrotoxicity through estimation of various proteins involved in natural defense mechanisms.

MATERIAL AND METHODS

HgCl2 (0.4 mg/kg) was administered to all groups (n = 5) except for the normal control. Three treatment groups received TQ (5, 10, and 15 mg/kg) 60 min before HgCl2 administration. The protective effect of TQ was evaluated from renal and liver function biomarkers, urine examination, glomerulus filtration rate (GFR), histopathological features, oxidative stress biomarkers, Hsp-70, apoptosis biomarkers, and gene expression.

RESULTS

TQ significantly attenuated hazardous effects of HgCl2 on renal and hepatic tissues. Urine albumin and glucose were considerably low in the treated groups in comparison with the HgCl2 group. TQ treatment also enhanced % GFR in rats. TQ-enhanced superoxide dismutase, catalase, and glutathione levels by enhancing the expression level of nuclear factor erythroid 2-related factor 2 (Nrf2). TQ increased Hsp-70 and Bcl-2 levels and reduced caspase-3 activity. TQ also protected cells against HgCl2-induced cell death and decreased % DNA fragmentation. TQ increased the expression of protective proteins metallothionein I and II and reduced the expression of kidney injury molecule-1 (Kim-1).

CONCLUSION

TQ showed protective effects against HgCl2-induced nephrotoxicity through modifications of various constitutive and inducible protein and enzyme levels in renal tissues.