[Protective effect of melatonin on oxidative stress inducing hair follicle injury in scald rat].
OBJECTIVE
To investigate the protective effect of melatonin on residual hair follicle cells of scald rats at early stage.


METHODS
Eighteen male Sprague-Dawley rats were randomly divided into scald group, treatment group, sham group , with 6 rats in each group. The rats in scald group and treatment group were subjected to 30% TBSA partial thickness scald on the back, and were resuscitated with balanced solution after 1 hour, while those in sham group were immersed in water at 37 degrees C for 25 s to simulate scald, and did not receive fluid replacement. Rats in treatment group were intraperitoneally injected with 10 mg/kg melatonin solution at 1 minute, 8 hours and 12 hours after scald, while those in sham group and scald group were given equal volume of 1% alcohol sodium-isotonic saline instead. Tissue samples were harvested at 6, 12 and 24 post scald hours (PSH) for determination of MDA and GSH levels. Apoptosis of residul hair follicle was detected by TUNEL method and immunohistochemistry of caspase-3.


RESULTS
The level of MDA in scald group at each time point was much higher than that in sham group (P < 0.01) and treatment group (P < 0.05), and it peaked at 12 PSH. The changes in GSH were just opposite to that of MDA. Under fluorescence microscope, the residual hair follicle cells were blue, and the apoptotic cells appeared green. The apoptosis rate in scald group at 6, 12, 24 PSH was obviously higher than that in sham (P < 0.01) and treatment groups (P < 0.05), which was (20.2 +/- 3.4)% vs (4.3 +/- 2.3)% vs (10.9 +/- 3.2)%, (31.2 +/- 3.6)% vs (5.1 +/- 2.5)% vs (19.1 +/- 3.7)%, (22.4 +/- 2.7)% vs (4.1 +/- 2.4)% vs (13.1 +/- 3.4)%, respectively. The score of caspase-3 positive cell in scald group was higher than those in sham group (P < 0.01) and treatment group (P < 0.05).


CONCLUSIONS
There is obvious correlation between oxidative stress and apoptosis rate of hair follicle cells in rats with partial thickness scald. Early administration of melatonin may have anti-apoptosis ability for residual hair follicle cells by attenuation of oxidative stress.
Jun
J
Zhang
Da-Hai
DH
Hu
Gang
G
Chen
Xiao-Zhi
XZ
Bai
Chao-Wu
CW
Tang
D000818:Animals; D017209:Apoptosis; D002056:Burns / Q000188:drug therapy* / Q000378:metabolism*; D018859:Hair Follicle / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley
D008550:Melatonin