Objective To explore the application value of
interleukin-33 (
IL-33) in
wound age estimation in forensic practice by observing the sequential changes of
IL-33 after
skin wound.
Methods Skin wound models were generated on the
back of
mice with a round file of 5 mm in diameter.
Skin samples of the same size were taken from the same parts of
mice in
control group and
injury group 1 h, 3 h, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d and 10 d after
skin wound.
Hematoxylin-
eosin (HE)
staining method was applied to observe the morphological changes in the recovering process after
skin wound.
Western blotting,
immunohistochemistry staining and double
immunofluorescence staining methods were applied to detect the expression changes of
IL-33 in the
skin wound samples. Results The results of
Western blotting showed that the expression of
IL-33 protein decreased slightly at 3 h after
skin wound, increased gradually at 6 h after
skin wound, and reached the peak value at 3 d, then decreased gradually.
Immunohistochemistry staining results showed that faint positive expression of
IL-33 was observed in
epidermis,
hair follicles,
sebaceous glands and dermal resident
cells of the
control group skin. The positive
cell rate of
IL-33 increased at 3 h after
skin wound and reached the peak value at 3 d, then decreased gradually. The results of double
immunofluorescence staining showed that the majority of
IL-33 positive
cells from 1 d to 3 d after
wound were
macrophages, while the majority of
IL-33 positive
cells from 5 d to 7 d after
wound were
myofibroblasts. In addition, the results of HE
staining showed that the
wound healing process of the
skin wound model was consistent with the pathological development
law of
inflammation. Conclusion
IL-33 could become a reference index for
wound age estimation of
skin wound in forensic practice.