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Background Mitochondrial dynamin-related protein 1 (DRP1) regulates mitochondrial division and plays an important role in maintaining hepatocyte function. However, the role of DRP1 in cadmium exposure-induced maternal liver damage in pregnant mice remains unclear. Objective To investigate the role and mechanism of DRP1 in maternal liver damage induced by cadmium exposure during pregnancy. Methods This study consisted of animal experiments and cell experiments. (1) Animal experiments. Mice at 14 days of gestation were randomly divided into three groups: a control group, a low-dose cadmium group (LCd group: 2.5 mg·kg−1), and a high-dose cadmium group (HCd group: 5 mg·kg−1). The pregnant mice were intraperitoneally injected with cadmium chloride (CdCl2) for 6 and 24 h in the next morning. The weights of pregnant mice, uterus, maternal liver, and fetal mice were recorded after sacrifice. Serum and liver of pregnant mice were collected, the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum were detected, and liver tissues were stained with HE to observe changes in liver function and liver tissue structure. The expressions of oxidative phosphorylation-related proteins, hypoxia inducible factor-1α (HIF-1α) and DRP1 proteins in liver of pregnant mice were detected by Western blotting. (2) Cell experiments. AML12 cells were treated with CdCl2 (10 μmol·L−1) for 0, 2, 6, 12, and 24 h. The expressions of oxidative phosphorylation-related proteins, DRP1, and hypoxia inducible factor-1α (HIF-1α) proteins were detected. AML12 cells were pretreated with DRP1 inhibitor Mdivi-1 for 1 h and then CdCl2 (10 μmol·L−1) for 12 h to detect the expression of oxidative phosphorylation-related proteins and DRP1 protein. AML12 cells were treated with Hif-1α siRNA for 48 h and CdCl2 (10 μmol·L−1) for 6 h to detect the expression of HIF-1α and DRP1 proteins. Results The results of animal experiments showed that cadmium exposure in pregnant mice had no effects on maternal liver weight and liver coefficient. However, the histomorphological changes and necrosis in hepatocytes were observed. Compared with the control group, the serum ALT and AST levels of pregnant mice in the LCd group were significantly increased after 6 h (P＜0.05), and the levels in the HCd group were significantly increased after 6 and 24 h (P＜0.05). Cadmium exposure during pregnancy significantly up-regulated HIF-1α and DRP1 expressions and down-regulated the expressions of oxidative phosphorylation-related proteins in maternal livers. In vitro cell experiments showed that the expressions of oxidative phosphorylation-related proteins was significantly decreased and HIF-1α and DRP1 protein expressions were significantly increased in the AML12 cells treated with CdCl2 for 6 h. Mdivi-1 pretreatment significantly antagonized the inhibitory effect of cadmium on the expressions of oxidative phosphorylation-related proteins in AML12 cells, while Hif-1α siRNA pretreatment significantly antagonized the up-regulative effect of cadmium on DRP1 expression in AML12 cells. Conclusion Cadmium exposure in pregnant mice may up-regulate DRP1 expression by activating HIF-1α signaling, then inhibit oxidative phosphorylation level of hepatic cells, and ultimately lead to maternal liver damage.
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Objective To explore the neuroprotection of Shuxuetongmai capsule pretreatment, and the effect on the expression of p38 mitogen-activated protein kinase (p38MAPK) in rats with middle cerebral artery occlusion. Methods Ninety-six male SD rats were divided randomly into sham-operated group,ischemia/reperfusion group (I/R),ischemia preconditioning group (IP),and Shuxuetongmai group(n=24). Each group was further randomly divided into 4 subgroups by 3 h, 6 h, 24 h and 72 h after reperfusion, 6 rats in each subgroup. Sham-operated group was only performed artery separation . The middle cerebral artery occlusion (MCAO) model was set up in I/R rats by Longa method. The IP rats were performed for three minutes on the bilateral carotid artery ligation, and formed MCAO model 24 hours later. The rats in the Shuxuetongmai group were pretreated with Shuxuetongmai capsules for 14 days on gavage before the establishment of MCAO model. The neurological deficits were graded in rats by Zea Longa method. Western Blot was used to determine the protein expression of p38MAPK and P-p38MAPK. Tunel method was applied to detect the apoptosis of neurons and the relationship between expression of p38MAPK, P-p38MAPK and apoptosis of neuron. Results No neurological dysfunction appeared in the sham-operated group at each time points, but not for the other groups, which reached the peak at 24 h. Compared with the I/R group, IP group and Shuxuetongmai group presented the mild neurologic function deficiency at different time points in rats (P0.05). The obvious variation of the value of P-p38MAPK/p38MAPK wasn't detected in sham-operated group at different time points, while obviously presented in I/R group, and the ratios of P-p38MAPK/p38MAPK were increased gradually followed with reperfusion, approaching to the highest level at 24 h. Compared with the I/R group, the P-p38MAPK/p38MAPK declined from 3 h and to the lowest level at 24 h of reperfusion, in both IP and Shuxuetongmai groups(P0. 05). Conclusion Shuxuetongmai capsule pretreatment can induce brain ischemic tolerance, attenuate the apoptosis of neurons in cerebral ischemia reperfusion, and improve neurologic function. The mechanism may be related to the inhibition of p38MAPK phosphorylation.