An experimental study on the relationship between the expression of GFAP and iNOS and the post-traumatic intervals after brain contusion in rats / 中国法医学杂志

ABSTRACT

Objective To observe the relationship between the expression of GFAP and iNOS the post-traumatic intervals after experimental cerebral contusion,in order to attempt to find out a method of timing wound age of brain contusion in the forensic prediction of injury time.Methods After setting up an model of experimental focal cerebral contusion in rats,immunohistochemical method was applied to observing the changes of inducible nitric oxide synthase (iNOS) and glial fibrillary acidic protein (GFAP) staining combined with histology method in rats.The immunostaining results were measured quantitatively with computer imaging analysis system.Results (1) At 3h after injury,GFAP-positive astrocytes around the wounded area were definitely detected.The intensity and the area of GFAP-positive cells increased following the post-traumatic intervals.The intensity peaked dually at 1d and 5d,respectively,followed by reduction at 3d,which revealed two-peak waveforms,The area of GFAP positive cells enhanced significantly at 3h and gradually increased with prolonging survival time,and reached a peak at 7d after injury.(2) At 12h after injury,the iNOS isoform was present and iNOS positive staining cells were noted.The intensity and the area of iNOS positive cells increased following the post-traumatic intervals.The area of positive reached maximal level at 1-3days,gradually subsided after 5d,and maintain a higher lever up to 7d post-injury;but the intensity of individual positive cell gradually increased with prolonging survival time,reached a peak at 5d and gradually subsided after 5d,but the level was still higher than the initial interval.Conclusions Expression of GFAP and iNOS is correlated with post-traumatic intervals after cerebral contusion in rats,suggesting that the expression of iNOS and GFAP may be served as the markers for timing of brain contusion in forensic practice.