[Intervention effect of apocynin on silicosis induced by silica in rats].

Objective: To investigate the intervention effect and its mechanism of apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) on silicosis induced by silica (SiO(2)) in rats. Methods: In October 2021, 24 SPF SD male rats were divided into control group, silicosis model group and apocynin intervention group according to random number table method, with 8 rats in each group. SiO(2) was exposed by one-time intratracheal instillation. The rats in the apocynin intervention group were intraperitoneally injected with apocynin 50 mg/kg, 3 times a week, on the second day after treatment. The rats were sacrificed 28 days later, and lung coefficients were calculated after lung tissues were weighed. Hematoxylin-eosin staining and Masson staining were used to observe the lung histopathological changes in each group, respectively. The levels of NOX, reactive oxygen species (ROS), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in lung tissue were detected. The expressions of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were determined by Enzyme-Linked Immunosorbent Assay (ELISA). The level of hydroxyproline (HYP) was detected by alkaline hydrolysate. The expressions of transforming growth factor beta 1 (TGF-ß1), E-cadherin (E-cad) and α-smooth muscle actin (α-SMA) in lung tissue were detected by Western blotting. Results: Compared with the control group, the body weight of silicosis model group was decreased, the lung tissue showed obvious inflammatory infiltration and fibrosis, and the levels of lung coefficient, IL-1ß, IL-6, TNF-α and TGF-ß1 were significantly increased (P<0.05). Compared with the silicosis model group, the lung tissue injury in the apocynin intervention group was significantly improved, the lung coefficient, NOX, ROS, MDA, IL-1ß, IL-6, TNF-α and TGF-ß1 levels were decreased, and the activity of GSH-Px was increased (P<0.05). Compared with the silicosis model group, the expressions of HYP and α-SMA were decreased and the level of E-cad was increased in the apocynin intervention group (P<0.05) . Conclusion: Apocynin may alleviate SiO(2)-induced fibrosis in silicosis rats by reducing oxidative stress, the release of inflammatory factors and inhibiting the process of epithelial-mesenchymal transition.

[Interventional effect of asiaticosdide on rats exposed to silica dust].

Objective: To investigate the effect of asiaticoside for fibrosis in lung tissues of rats exposed to silica and to explore its possible mechanism. Methods: 144 SD male rats were randomly divided into control group, model group, positive drug control group, asiaticoside high-dose group, medium-dose group and low-dose group, each group included 24 rats. Rats in the control group were perfused with 1.0 ml of normal saline, and the other groups were given 1.0 ml 50 mg/ml SiO(2) suspension. Gavage of herbal was given from the next day after model establishment, once a day. Rats in the positive drug control group were administration with 30 mg/kg tetrandrine and rats in the low-dose group, medium-dose group and high-dose group were given 20 mg/kg, 40 mg/kg and 60 mg/kg asiaticoside for fibrosis respectively. Rats in the control group and the model group were given 0.9% normal saline. The rats were sacrificed in on the 14th, 28th and 56th day after intragastric administration and collect the lung tissues to detect the content of hydroxyproline, TGF-ß(1) and IL-18, observe the pathological changes of the lung tissues by HE and Masson staining and determine the expressions of Col-I, a-SMA, TGF-ß in lung tissues by Western Blot. Results: On the 14th day, 28th day and 56th day after model establishment, the lung tissues of rats in the model group showed obvious inflammatory response and accumulation of collagen fibers, and the degree of inflammation and fibrosis increased with time. The intervention of asiaticoside could effectively inhibit the pathological changes of lung tissues. The contents of hydroxyproline, IL-18 and TGF-ß1 in lung tissues of model group were higher than those in the control group (P<0.05) , while the level of hydroxyproline, IL-18 and TGF-ß1 in asiaticoside groups were significantly decreased, and the difference was statistically signicant (P<0.05) . Compared with the control group, the expression levels of Col-I, TGF-ß1and α-SMA in lung tissue of model group were increased (P<0.05) , while the expression level of Col-I, TGF-ß1 and α-SMA were decreased after the intervention of asiaticoside, and the difference was statistically signicant (P<0.05) . Conclusion: Asiaticoside can inhibit the increase of Col-I, TGF-ß1 and α-SMA content in the SiO(2)-induced lung tissues of rats, reduce the release of TGF-ß1 and IL-18 inflammatory factors in lung tissue, and then inhibit the synthesis and deposition of extracellular matrix in rat lung tissue, and improve silicosis fibrosis.

[Study on baicalin on liver and kidney toxicity in male rats].

Objective: To observe the toxic effects of different doses of baicalin on liver and kidney of rats after different time administration, and provide experimental reference for the safety of clinical medication. Methods: In April 2019, 42 Wistar male rats were randomly divided into a control group (0.9% sodium chloride solution) and baicalin administration groups (100, 200 mg/kg) , 14 rats in each group, and one was given by oral gavage. 7 times/d, 6 times/week, 7 rats in each group were sacrificed 28 and 56 days after the administration. The wet weights of liver and kidney were weighed and the organ coefficients were calculated. The hematoxylin-eosin (HE) staining was used to detect the histomorphological changes. And the levels of serum alanine aminotransferase (ALT) , aspartate aminotransferase (AST) , alkaline phosphatase (ALP) , blood urea nitrogen (BUN) and creatinine (CRE) were detected. Results: After 56 days of administration in baicalin 200 mg/kg rats, the body weight and kidney coefficient were lower than those of the control group. Histopathology showed that glomerular atrophy became smaller, renal tubules were significantly atrophied, and epithelial cell necrosis occurred. No obvious abnormalities in liver was observed. After 56 days of administration in baicalin 200 mg/kg rats, the levels of BUN and CRE in the serum were higher than those of the control group, and the differences were statistically significant (P<0.05) . There were no obvious abnormalities in the baicalin 100 mg/kg group and the 28 d of administration in baicalin 200 mg/kg group. Conclusion: Under the conditions of this test, baicalin has certain renal toxicity in male rats.

[Repair effect of adipose-derived mesenchymal stem cells on lung injury in rats exposed to silica].

Objective: To observe the repairing effect of adipose mesenchymal stem cells (ADSCs) on lung injury induced by silica in rats. Methods: Primary ADSCs-GFP was obtained from rats. ADSCs-GFP was injected into tail vein of silicosis model rats. The expression of green fluorescence in lungs was observed regularly to determine the homing ability of ADSCs. Primary ADSCs of rats were obtained and randomly divided into control group, exposure group, vehicle group and ADSCs group. Silicosis rat model was established by non-exposed tracheal drip method. 24 hours after silica exposure, rats in ADSCs group were injected with ADSCs of 1×10(6)/kg body weight through tail vein, and the pathological changes of lung tissue were observed and evaluated 28 days after intervention. To explore the early intervention mechanism of ADSCs on pulmonary fibrosis in silicosis model rats, apoptosis-related proteins were detected by immunohistochemistry. Results: 28 days after exposure to silica, rats in the exposure group showed obvious pulmonary fibrosis. Compared with exposure group and vehicle group, ADSCs group showed less pulmonary inflammation, less silica nodules and less collagen deposition area. Immunohistochemical results showed that the expression of Caspase-3 and cytochrome C protein decreased and Bcl-2 protein increased after ADSCs transplantation. Conclusion: ADSCs infusion has an obvious intervention effect on postponing early silicosis fibrosis in rats exposed to silica, and its mechanism is related to the regulation of apoptotic process.

[Lung fibrosis and changes in autophagy-related proteins in rats exposed to silica dust].

Objective: To explore the changes in the autophagy marker microtubule-associated protein 1 light chain 3 (LC3) and yeast autophagy-related gene 6 (Beclin1) in rat lungs exposed to free silica (SiO(2)) dust for different periods. Methods: A total of 72 male specific pathogen-free Wistar rats were randomly divided into solvent control group and SiO(2) model group. The SiO(2) model group received one-time non-exposed intratracheal instillation of suspension of SiO(2) particles to establish a model of silicosis. The solvent control group received an equal amount of saline. Six rats each were sacrificed at 1, 7, 14, 21, 28, and 60 days after model establishment. The pathological changes and fibrosis of rat lungs at different time points were evaluated by H&E staining and Masson staining, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of transforming growth factor-ß (TGF-ß) , interleukin-1 (IL-1) , and tumor necrosis factor-α (TNF-α) in lung tissue homogenate. Western blot was used to determine the relative expression levels of LC3 and Beclin1 in the lung tissue. Results: The results of H&E staining showed that the model group had continuous inflammation in the lung tissue from day 1 to day 60, and the inflammatory scores were significantly higher in the model group than in the control group (P<0.05) . The results of Masson staining showed that rats in the model group had a small amount of collagen fibers in the lung tissue on day 14 and a large amount of collagen fibers on day 60. The fibrosis score was significantly higher in the model group than in the control group (P<0.05) . No collagen fibrosis was observed in the lung tissue in the control group. The results of ELISA showed that the model group had significantly higher levels of IL-1, TNF-α, and TGF-ß in lung tissue homogenate than the control group at each time point after exposure (P<0.05) . The results of Western blot showed that the model group had decreased expression of Beclin1 protein in the lung tissue on days 7, 14, 21, 28, and 60, which was significantly higher than that of the control group (P<0.05) . The model group also had a decreased ratio of LC3II/LC3I on days 1, 7, 14, 21, 28, and 60, which were significantly higher than that of the control group (P<0.05) . Conclusion: In the rat model of silicosis induced by free SiO(2) dust, the expression levels of autophagy-related proteins, LC3 and Beclin1, are correlated with different stages of silicosis. In the early stage of silicosis, the lung tissue has inflammation, substantially increased ratio of LC3II/LC3I and expression of Beclin1, and active autophagy. With the progression of silicosis, the ratio of LC3II/LC3I and expression level of Beclin1 gradually decrease and autophagy becomes weak.

[Effects of malathion on testicular enzyme activities and sperm quality of male rats].

OBJECTIVE: The aim of this study is to investigate the effects of sub chronic exposure to malathion on testicular enzyme activities and sperm quality of male rats. METHODS: Forty male rats were divided into four groups: three exposure groups and a control group. Malathion was administered orally to male rats at 0, 33.75, 54.00, and 108.00 mg/kg for 60 days to evaluate the toxic alterations in sperm dynamics and testicular enzyme activities including ACP,LDH,SDH and γ-GT. The control rats were administered with an equivalent volume of distilled water in the same manner.After sacrificed, the testes were collected and weighed. RESULTS: The body weight and the testis weight of animals showed a decreasing tendency, and there was a statistical difference between the 54.00, 108.00 mg/kg groups, and the control group (P<0.05). Malathion brought about marked reduction in testicular sperm counts, sperm motility, and significant growth of sperm malformation rate in 108.00 mg/kg group. A significant decrease in the activities of testicular enzyme ACP and γ-GT was observed in malathion exposed rats, while the activities of LDH was significant increased and there were no obvious effects on the activities of SDH. The activities of ACP, γ-GT and LDH showed a statistical difference between the 108.00 mg/kg groups, and the control group. CONCLUSION: Malathion reduced the sperm counts and sperm motility, increased the malformation rate and reduced the activities of testicular enzymies of male rats.