Time-dependent expression of skeletal muscle troponin I mRNA in the contused skeletal muscle of rats: a possible marker for wound age estimation

Abstract

To estimate the age of skeletal muscle contusion, the expression of troponin I mRNA in contused skeletal muscle of rats was detected using real-time polymerase chain reaction (PCR). A total of 51 Sprague-Dawley male rats were divided into control and contusion groups, and another nine rats received contusion injury after death. At 0.5, 1, 6, 12, 18, 24, 30, and 36 h after contusion, the rats were killed with a lethal dose of pentobarbital. Total RNA was isolated from muscle specimens using the SV Total RNA Isolation System and reverse transcribed into first-strand cDNA. Sequence-specific primers were then used to conduct real-time PCR to analyze the expression levels of sTnI mRNA. At 0.5, 1, and 6 h after contusion, the expression levels of sTnI mRNA decreased to 78.17% (P < 0.05), 41.58% (P < 0.05), and 32.13% of that in the control group, respectively. However, there were no significant changes in the expression levels of sTnI mRNA from 6 to 36 h (P > 0.05) after contusion when normalized to RpL32 expression. The expression levels of sTnI mRNA in the normal and contused skeletal muscle of postmortem rats were about 70% of that in the control group (P < 0.05), and no significant changes in the expression levels of sTnI mRNA in the postmortem contusion group were noted among different time points after injury. This result suggests that determination of sTnI mRNA levels by real-time PCR is useful for the estimation of wound age.

The cannabinoid receptor type 2 is time-dependently expressed during skeletal muscle wound healing in rats

“…It was interesting to note that there was significant difference in the CB2R to GAPDH ratios between 3 and 6 h post-injury as detected by Western blotting and RT-PCR in our study. However, in the previous investigation, immunohistochemical staining was restricted in practical application, especially for the estimation of wound age less than 8 h, because it was not accurate and stable in semiquantitative analysis, and the results may be influenced by investigators [35]. Thus, in the present study, detection of protein and mRNA by Western blotting and RT-PCR was more suitable for wound age estimation, which was usually more stable and sensitive than immunohistochemical assays.…”

“…According to previous study, the expression of troponin I mRNA could give significant information about the age determination of skeletal muscle contusion and rat samples with known post-infliction intervals were employed [35]. There are many studies on the ultrastructure and pathophysiological development of skeletal muscle contusion healing using a mechanical blunt trauma model in rodents [36][37][38], and it is considered that the experimental model mimicked the damage-repair process in human skeletal muscle with a high degree of accuracy and objectivity.…”

Yara Yaşı ve Canlılık Değerlendirmesinde Güncel Yaklaşım

“…ise doku plazminojen aktivatörü (tPA) ve fibroblast büyüme faktö-rü (bFGF)'nün mRNA ekspresyonlarına dayanarak yara yaşı tespitine yönelik çalışmalar yapmışlardır (48,49) . Farelerde çeşitli genlerde mRNA analizine yönelik çalış-malarda c-fos, fos-B ve MKP-1'in erken dönemlerde yara yaşı tayininde yararlı olabileceği bulunmuştur (50,51). Literatürde RNA'nın en büyük üstünlüğünün zamana bağlı olarak eksprese edilebilmesi olduğu, bu şekilde yara yaşı tahmininde güvenli sonuçlar elde edilmesini sağladı-ğı bildirilmektedir.…”

Vitality and wound-age estimation in forensic pathology: review and future prospects

“…After wounding, however, the mRNA levels of cytokines and enzymes typically change sooner than the protein levels and the histomorphology [25][26][27][28]. Hence, assays based on mRNA are suitable for estimating the age of early-stage wounds.…”

“…Wound healing comprises inflammatory, proliferative, and maturation phases, which involve interactions between various cell types and soluble factors [25,[39][40][41]. During the inflammatory phase, a variety of chemokines are released at the injured site, leading to the recruitment of inflammatory cells, such as neutrophils and macrophages.…”