Role of oxidative stress-induced AMPK/ULK1 pathway activation and lysosomal dysfunction in arsenic-induced liver injury in rats / 环境与职业医学

Background A prominent feature of endemic arsenic poisoning is severe liver damage. Studies have found that liver injury is closely related to oxidative stress, lysosomes, and autophagy. Objective Through establishing a liver injury model of rats by sodium arsenite (NaAsO2)administration in drinking water, this experiment is designed to explore the roles of oxidative stress, lysosomes, and AMP activated protein kinase (AMPK)/Unc-51 like kinase 1 (ULK1) pathway in this model. Methods Twenty-four Wistar rats were randomly divided into four groups with six rats in each group (half male and half female), including control group and 25, 50, 100 mg·L−1 NaAsO2 groups. A rat liver injury model was established by drinking water containing NaAsO2 freely for 24 weeks. Then liver of rats was dissected after sacrificed, and the levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bile acid (TBA), catalase (CAT), lipid peroxidation (LPO), and total antioxidant capacity (T-AOC) in liver tissues were detected by assay kits. The levels of lysosomal-associated membrane protein 2 (LAMP2), cathepsin B (CTSB), and acid phosphatase (ACP2) were determined by enzyme linked immunosorbent assay. The mRNA transcriptional expressions of AMPK, ULK1, microtubule-associated protein light chain 3 (LC3), and sequestosome 1 (p62) were detected by real-time fluorescence quantitative PCR (RT-qPCR). The protein expressions of p-AMPK, p-ULK1, LC3, and p62 were detected by immunohistochemistry. Results Following the NaAsO2 administration, significant differences were found in the levels of ALT, ALP, and TBA among the designed groups (F=12.09, 72.11, and 23.58, P<0.05). Compared with the control group, the levels of ALT in the 50mg·L−1 and 100 mg·L−1 NaAsO2 groups were increased (P<0.05); the levels of ALP and TBA in the 25, 50, and 100 mg·L−1 NaAsO2 groups were increased (P<0.05); the level of LPO in the 100 mg·L−1 group was increased (P<0.05); the levels of CAT and T-AOC in the 25, 50, and 100 mg·L−1 NaAsO2 groups were decreased (P<0.05). According to the results of enzyme linked immunosorbent assay, the levels of ACP2 in the 25, 50, and 100 mg·L−1 NaAsO2 groups, the level of CTSB in the 100 mg·L−1 NaAsO2 group, and the levels of LAMP2 in the 50 and 100 mg·L−1 NaAsO2 groups were decreased compared with the control group (P<0.05). Based on the results of RT-qPCR and immunohistochemistry, the mRNA transcriptional and protein expressions of AMPK, ULK1, and LC3 in some arsenic groups were elevated to varying degrees compared with the control group, and the increment in the 100 mg·L−1 NaAsO2 group was significant for all the indicators (P<0.05); the mRNA transcriptional expressions of p62 in the three arsenic groups and the protein expressions of p62 in the 50 and 100mg·L−1 NaAsO2 groups also increased compared with the control group (P<0.05). Besides, the results of Pearson correlation analysis showed that there was a positive correlation of T-AOC with LAMP2, CTSB, and ACP2 (r=0.651, 0.673, 0.626; P<0.05), a negative correlation of LPO with CTSB and ACP2 (r=−0468, −0.482; P<0.05), a negative correlation of p62 with LAMP2, CTSB, and ACP2 (r=−0.57, −0.626, −0.591; P<0.05), and a positive correlation of p62 with ALT, ALP, and TBA (r=0.709, 0.897, and 0.857, P<0.05). Conclusion Long-term arsenic exposure may induce oxidative stress, damage lysosomes, and activate the AMPK/ULK1 pathway, which can lead to the blockage of autophagy process, and eventually result in liver damage.

Radiation injury of interstitial implantation 125I seeds on normal trachea tissue of rabbits / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the radition injury of tracheal mucous membrane tissue after interstitial implanted radioactive 125I in normal rabbit,improve the safety of clinical application.@*METHOD@#Sixty New Zealand rabbits, weighing 2.15-2.30 kg, were randomly divided into 1 w, 1 m, 2 m, 4 m and the control group, the control group was further divided into four subgroups. The 0.8mCi 125I seeds were implanted into the tissue by the first tracheal ring in the treatment groups and nonradioactive seeds were implanted in the control group. Taking the tracheal mucous membrane tissue for pathological examination by HE staining to observe the mucosal injury and VEGF, Pan-Cadherin immunohistochemical staining to observe the expression in differernt time.@*RESULT@#Immunohistochemical staining: VEGF and Pan-Cadherin have statistically significant differences in the expression on different time, the expression is dynamic.@*CONCLUSION@#The expression of VEGF and Pan-Cadherin reflect the radioactive 125I seed has little influence on normal trachea tissue and the damage can be repaired by the regeneration of the basal cell.

Mycoplasma contamination decreases 28S and 18S RNC-rRNA via p38 MAPK pathways in human cell lines / 中国病理生理杂志

AIM:To evaluate the effect of mycoplasma on the rRNA composition of mature ribosomes in human cell lines.METHODS:We isolated ribosome nascent-chain complex ( RNC) from multiple mycoplasma-positive-negative human cell lines.RNC-RNA was acquired from each cell line through RNA extraction, followed by agarose gel separation, fluorescent visualization and gray-scale value measurements on the rRNA bands.Western blot analysis was performed to in-vestigate the MAPK pathway alterations.RESULTS:In various human cell lines derived from different tissues, we found that as compared with mycoplasma-negative cells, mycoplasma-positive cells showed aberrant RNC-rRNA band patterns, featured by the decreases in 28S and 18S eukaryotic rRNAs and the increases in 16S and other unknown prokaryotic rRNAs.When cultured without ciprofloxacin, mycoplasma-negative HBE cells acquired mycoplasma contamination as ob-served with such characteristic abnormal rRNA bands.The ciprofloxacin treatment was able to recover the RNC-rRNA bands of the mycoplasma-contaminated cells to the normal pattern.The results of Western blot analysis on total and phos-phorylated proteins indicated that p38 pathway was significantly deactivated in mycoplasma-infected A549 cells, while ERK1/2 pathway was not significantly altered.CONCLUSION:Mycoplasma contamination severely alters the RNC-rRNA composition via p38 MAPK pathway, thus seriously impacting on the host cell translational behaviors.