[Pathologic changes and expression of Heme oxygenase-1 in paraquat-induced renal injury]

To study the mechanism of paraquat-induced renal injury in rats.

Adult healthy Sprague-Dawley (SD) rats (female and male in half) were randomly divided into two groups, the control group and the paraquat poisoned group. The rats in the paraquat poisoned group were treated with PQ (25 mg/kg) intraperitoneally while the rats in the control group were treated with the same dose of normal saline. Its histopathological change was observed and the expression of HO-1 and the mRNA expression of HO-1 were detected by RT-PCR at 3rd h, 6th h, 12th h, on 1st d, 2nd d, 3rd d and 5th d.

(1) In the control group, the tissue structure was clear without edema, vacuolar degeneration, cloudy swelling and necrosis. In the paraquat poisoned group, there were obvious lesions in the renal tubule of cortical part, including cellular swelling, the narrow cannula, the mesenchymal congestion and edema. These pathologic changes gradually became more severe, reached the peak on the 1st day, and did not relieve until the end of this study; there was the karyopyknosis and the cyto-architecture disappeared in some severe cases; Some glomerulus and medulla were also involved. (2) In the control group, there was no or weak expression of HO-1 and HO-1 mRNA. At the 3rd hour, the expressions of HO-1 in the paraquat poisoned group were observed in the membrane and cytoplasm of renal tubular epithelial cell of cortical part. Immunohistochemistry score (IHS) in the paraquat poisoned group was higher than that in the control group (P<0.05), except the HIS of the 5th day. At the 3rd hour, the expression of HO-1 mRNA increased, reached the peak on the 1st day, and then decreased. The expression of HO-1 mRNA was (0.53 +/- 0.21), (0.55 +/- 0.31), (0.56 +/- 0.22), (0.64 +/- 0.14) and (0.43 +/- 0.25) at the time point other than on the 3rd and 5th day. It showed statistical difference between the paraquat poisoned group and the control group from the 3rd hour to the 2nd day (P<0.05).

The mechanism of paraquat induced-renal injury is multiple. The higher expression of HO-1 and HO-1 mRNA were involved in the procedures of paraquat-induced renal injury.