The aim of the present study was to determine the roles of the chemotactic factor, chemokine ligand 2 (CCL2), and its receptor, chemokine receptor type 2 (CCR2), in the hippocampus of rats with cerebral ischemia/reperfusion injury. In total, 24 Sprague‑Dawley rats, weighting 250‑300 g, were randomly divided into three groups (n=8): Sham‑operated (C group), cerebral ischemia/reperfusion injury (I/R group) and propofol‑intervention (P group) groups. The rats were sacrificed at 6 h after the ischemia/reperfusion surgery, and the brains were obtained to isolate the hippocampus. The mRNA expression levels of CCL2 and CCR2 in the hippocampus were analyzed by quantitative polymerase chain reaction, while the protein expression levels of CCL2 and CCR2 were determined by western blot analysis. The expression levels of CCL2 and CCR2 in the procerebrum were markedly elevated in the I/R and P groups at 6 h after the ischemia/reperfusion surgery when compared with the C group (P<0.05). In addition, the mRNA expression levels of CCL2 and CCR2 decreased significantly in the P group as compared with that in the I/R group (P<0.05). Therefore, CCL2 and CCR2 may be involved in the mechanisms underlying cerebral ischemia/reperfusion injury, and propofol may protect the brain through regulating the expression of CCL2 and CCR2.

With the advantages of ultrahigh resolution and acquisition rate, line scan cameras are increasingly being deployed for precision measurement. In order to achieve high precision, the intrinsic parameters must be calibrated properly. However, the existing calibration models that only calibrate the principle points and the distortion on one-dimensional direction and ignore the other directions result in limited adaptability and accuracy, which are especially serious for multiline cameras. To conquer this challenge, this paper proposes a precise calibration method which is qualified both for multiline cameras and single-line cameras. Through the analysis of the relative position relationship between pixel array and principle point, a method for calibrating the principle points and the distortion on two-dimensional direction is proposed and a flexible calibration device is designed based on a theodolite. The calibration quality is improved by the novel calibration method which effectively establishes the correspondence relationship between the rays and pixels by recording incident angle of collimated beam and its image respectively. Moreover, a robust optimization algorithm is proposed to enhance the stability of parameter estimation. The proposed method is verified by Monte-Carlo simulation, real experimental data and flight, the results show that the two-dimensional calibration model can improve the calibration accuracy of the multiline cameras by 45 pixels at most and its re-projection measurement uncertainty is as low as 0.1 pixels. The comparative results of the experiments demonstrate that the proposed method has the advantages of high accuracy, low cost, and easy implementation.