Different extent of hypoxic-ischemic brain damage in newborn rats: histopathology, hemodynamic, virtual touch tissue quantification and neurobehavioral observation.

OBJECTIVE: To explore the correlation between pathological and ultrasound changes applying conventional ultrasound, Color Doppler ultrasound andVirtual Touch Tissue Quantification (VTQ) technique in newborn hypoxic-ischemic brain damage (HIBD) rat models. To provide theoretical basis for early diagnosis and treatment of HIBD neonatal.

METHODS: A total of 90 newborn Wistar rats were divided into ischemia, asphyxia and control group according to different HIBD molding methods. Conventional ultrasound, Color Doppler ultrasound and VTQ were applied on 3 h, 12 h, 24 h, 48 h and 72 h postoperative. After the observation of 72 h, 10 rats in each group were randomly selected for pathological specimens production. The rest rats were raised for 30 days for neuroethology detection.

RESULTS: In ischemia group and asphyxia group, there were 4 deaths and 6 deaths in the modeling process; the mortality rate was 13.33% (4/30) and 20.00% (6/30) respectively. For ischemia group, the systoli velocity (Vs), diastolic velocity (Vd) and resistance index (RI) of right middle cerebral artery (MCA) were significantly decreased after operation (P<0.05). For asphyxia group, the Vs and RI of right MCA were significantly decreased after operation (P<0.05), while the Vd of right MCA was significantly increased after operation (P<0.05), which lead to the postoperative RI value in each time point was all significantly lower than that in ischemia group (P<0.05). For ischemia group and asphyxia group, the VTQ results increased significantly postoperative (P<0.05), and compared with ischemia group and control group, the postoperative VTQ value in each time point was all significantly higher in asphyxia group (P<0.05). The neuroethology results were significantly lower in the ischemia group and asphyxia group (P<0.05), and the results in ischemia group were significantly higher than those of asphyxia group (P<0.05). And the results are consistent with the pathological findings.

CONCLUSION: There is a consistent correlation among histopathological changes, hemodynamic changes, VTQ values and neuroethology results in HIBD animal models. As noninvasive quantitative ultrasound elastography methods, Color Doppler ultrasound and VTQ can assess the extent of HIBD damages in newborn rats with specific values. This study provides basic research and theory to early diagnosis and early treatment of neonatal hypoxic-ischemic brain damage.