Linkages of soil CO2 emission with plant functional traits in young subtropical plantations.

Soil respiration is a key process in forest biogeochemical cycling. Exploring the relationship between plant functional traits and soil respiration can help understand the effects of tree species conversion on soil carbon cycling. In this study, we selected 15 common subtropical tree species planted in the logging site of second-generation Chinese fir forest to measure soil CO2 emission fluxes, soil physicochemical properties, leaf and root functional traits of each species, and explored the effects of plant functional traits on soil respiration. The results showed that the annual flux of soil CO2 emissions varied from 7.93 to 22.52 Mg CO2·hm-2, with the highest value under Castanopsis carlesii (22.52 Mg CO2·hm-2) and the lowest value under Taxus wallichiana (7.93 Mg CO2·hm-2). Results of stepwise regression analysis showed that the annual flux of soil CO2 emission decreased with the increases of leaf nitrogen content and fine root diameter, and increased with increasing leaf non-structural carbohydrate. In the structural equation model, leaf non-structural carbohydrate had a direct and significant positive effect on soil CO2 emission fluxes, while leaf nitrogen content and fine root diameter had a direct negative effect by decreasing soil pH and soluble organic nitrogen content. Plantations of different tree species would affect soil CO2 emission directly by changing functional traits related to water and nutrient acquisition or indirectly through soil properties. When creating plantations, we should select tree species based on the relationship between plant functional traits and ecosystem functions, with a view to improving forest productivity and soil carbon sequestration potential.

Phosphorus limitation induced by nitrogen addition changed soil microbial community structure in a subtropical Pinus taiwanensis forest.

Soil microorganisms play an important role in the biogeochemical cycles of terrestrial ecosystems. How-ever, it is still unclear how the amount and duration of nitrogen (N) addition affect soil microbial community structure and whether there is a correlation between the changes in microbial community structure and their nutrient limi-tation status. In this study, we conducted an N addition experiment in a subtropical Pinus taiwanensis forest to simulate N deposition with three treatments: control (CK, 0 kg N·hm-2·a-1), low N (LN, 40 kg N·hm-2·a-1), and high N (HN, 80 kg N·hm-2·a-1). Basic soil physicochemical properties, phospholipid fatty acids content, and carbon (C), N and phosphorus (P) acquisition enzyme activities were measured after one and three years of N addition. The relative nutrient limitation status of soil microorganisms was analyzed using ecological enzyme stoichiometry. The results showed that one-year N addition did not affect soil microbial community structure. Three-year LN treatment significantly increased the contents of Gram-positive bacteria (G+), Gram-negative bacteria (G-), actinomycetes (ACT), and total phospholipid fatty acids (TPLFA), whereas three-year HN treatment did not significantly affect soil microbial community, indicating that bacteria and ACT might be more sensitive to N addition. Nitrogen addition exacerbated soil C and P limitation. Phosphorus limitation was the optimal explanatory factor for the changes in soil microbial community structure. It suggested that P limitation induced by N addition might be more beneficial for the growth of certain oligotrophic bacteria (e.g. G+) and the microorganisms participating in the P cycling (e.g. ACT), with consequences on soil microbial community structure of subtropical Pinus taiwanensis forest.

[Effects of root growth on leaf litter decomposition and enzyme activity in litter layer]. / æ ¹ç³»åœ¨å‡‹è½ç‰©å±‚ç”Ÿé•¿å¯¹å‡‹è½å¶åˆ†è§£åŠé ¶æ´»æ€§çš„å½±å“.

The growth of roots towards aboveground litter layer is a common phenomenon in forest ecosystems. It is of great significance to examine the effects of root presence on litter decomposition for understanding nutrient cycling in forest ecosystems. We explored the effects of root growth on leaf litter decomposition, nutrient release and enzyme activities by establishing treatments with and without root with a one year field decomposition experiment in Phoebe zhennan and Castanopsis kawada-mii forests at Sanming, Fujian. The results showed that after 360 days decomposition, leaf litter mass remaining ratio in the treatment with root was 8.4% and 19.7% lower than control, respectively. The presence of root exhibited significant effect on litter decomposition during the 90-180 days. Compared with the control, the remaining ratio of leaf litter carbon, nitrogen and phosphorus were 6.0%, 19.1% and 20.6% lower in the treatment with root in the P. zhennan forest, and were 21.3%, 23.2% and 20.5% lower in the C. kawadamii forest, respectively. During the whole decomposition process, root presence did not affect the hydrolytic enzyme activity. After 180 days decomposition, the peroxidase activities in the treatment with root were 111.4% and 92.4% higher than control in the P. zhennan and C. kawadamii forests, respectively. The remaining ratio of leaf litter carbon, nitrogen and phosphorus were negatively correlated with the activities of cellobiohydrolase, ß-glucosidase, acid phosphatase, and peroxidase. Root presence in litter layer could accelerate litter decomposition and nutrient release through nutrient uptake and stimulation of oxidase activity.

[Soil C:N:P stoichiometry and nutrient dynamics in Cunninghamia lanceolata plantations during different growth stages]. / 不同生长阶段杉木人工林土壤C∶N∶PåŒ–å­¦è®¡é‡ç‰¹å¾ä¸Žå »åˆ†åŠ¨æ€.

We investigated soil C:N:P stoichiometry and nutrient dynamics of Cunninghamia lanceolata plantations at different stand ages (5, 8, 21, 27 and 40 years old) in Fujian Baisha Fores-try Farm. We measured the concentrations of soil total carbon (TC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), total calcium (Ca), total magnesium (Mg), and soil C:N:P stoichiometry at 0-10, 10-20, and 20-40 cm soil layers during different growth stages. The results showed that soil TC and TN concentrations and C:N remained unchanged during stand development. Soil TP content showed an increase-decrease-increase trend with increasing stand ages. Soil TP content was lowest, whereas C:P and N:P were highest at the mature stage of C. lanceolate plantation in the 0-10 and 10-20 cm soil layers. However, soil TP content showed no significant differences in all stand ages at the 20-40 cm soil layer. The contents of Ca and Mg were lowest at the mature stage of C. lanceolata stand. The TC was positively correlated with soil C:N, C:P and N:P. The TP was significantly and negatively correlated with soil C:P and N:P. Soil TP was a key factor regulating soil C:P and N:P stoichiometry. The development of mature plantation was mainly limited by soil P availability. To sustain the development of C. lanceolata plantations and improve nutrient cycling, phosphorus fertilizer could be applied during the rapid growth period of C. lanceolata. In addition, an appropriate extension of the rotation period of C. lanceolata plantation could facilitate soil nutrient restoration.

[Effects of broadleaved tree species on soil microbial stoichiometry in clear-cut patches of Cunninghamia lanceolata plantation]. / æ‰æœ¨é‡‡ä¼è¿¹åœ°è¥é€ é˜”å¶æ ‘ç§å¯¹åœŸå£¤å¾®ç”Ÿç‰©ç”Ÿæ€åŒ–å­¦è®¡é‡ç‰¹å¾çš„å½±å“.

Investigating the response of soil microbial biomass and ecological stoichiometry to tree species transition is of great significance for understanding soil nutrient cycling and availability in forest ecosystems. We measured soil microbial biomass carbon (MBC), nitrogen (MBN), phosphorus (MBP) and their stoichiometry across 0-40 cm soil depth between Mytilaria laosensis and Cunninghamia lanceolata plantations by the chloroform fumigation extraction method, which were replanted after the harvest of C. lanceolata plantation. The results showed that soil MBC in the 0-10 cm layer and soil MBN and MBP in the 0-20 cm layer under the M. laosensis were significantly higher than those under the C. lanceolata. The MBC/MBP in the 0-20 cm layer and MBN/MBP in the 10-20 cm layer were significantly lower under the M. laosensis plantation. The MBC/MBN showed no significant differences between the two forests. Soil moisture, organic carbon, total nitrogen, total phosphorus, available phosphorus were positively correlated with MBC, MBN and MBP, but negatively correlated with MBC/MBP and MBN/MBP. Results of stepwise linear regression analysis showed that MBN and MBP were mainly affected by soil total nitrogen and available phosphorus, while MBC/MBP and MBN/MBP were mainly driven by available phosphorus and organic carbon, respectively. Our results indicated that tree species transition from C. lanceolata to M. laosensis could increase soil microbial biomass in the surface layers, accelerate soil nutrients turnover and enhance soil nutrient supply. The increases of MBP under M. laosensis indicate alleviation of soil phosphorus limitation for tree growth.

[Effects of broadleaved tree plantation on soil phosphorus fractions and availability in diffe-rent soil layers in a logged Cunninghamia lanceolata woodland]. / æ‰æœ¨é‡‡ä¼è¿¹åœ°è¥é€ é˜”å¶æ ‘å¯¹ä¸åŒå±‚æ¬¡åœŸå£¤ç£·ç»„åˆ†å’Œæœ‰æ•ˆæ€§çš„å½±å“.

Phosphorus (P) limitation is one of the major issues for the management of subtropical plantations. Understanding the effects of tree species transition from conifer to broadleaved trees on soil P fraction and availability in different soil layers are of great significance for the sustainable development of subtropical forests. We compared changes in soil chemical properties, P fraction and availability across 0-100 cm soil profile between Mytilaria laosensis and Cunninghamia lanceolata plantations, which were initially reforested from C. lanceolata plantation in the spring of 1993. The results showed that soil organic P content in both plantations decreased significantly with soil depth. Compared with C. lanceolata, the M. laosensis plantation significantly increased soil available P content by 35.7% and 86.2% in the 0-10 and 10-20 cm, respectively. The contents of soil labile P and moderately labile P decreased significantly with soil depth in both plantations. The contents of labile P and moderately labile P were significantly higher in the surface soil (0-20 cm), while the non-labile P in the 80-100 cm was increased by 13.6%, and the free iron content in the 20-80 cm significantly decreased. Results of redundancy analysis showed that dissolved organic carbon and free iron were the most important factors influencing P fraction in those plantations. Tree species transition from C. lanceolata to M. laosensis could change the pattern of soil P fraction in soil profile, and greatly enhance soil P availability.

[Dynamics of nutrient concentration and microbial community composition during fine root decomposition in subtropical Mytilaria laosensis and Cunninghamia lanceolata plantations.] / äºšçƒ­å¸¦ç±³è€æŽ’å’Œæ‰æœ¨ç»†æ ¹åˆ†è§£è¿‡ç¨‹ä¸­å »åˆ†ä¸Žå¾®ç”Ÿç‰©ç¾¤è½ç»„æˆçš„å˜åŒ–.

We conducted a 12-month fine root decomposition experiment under 19-year-old Mytilaria laosensis and Cunninghamia lanceolate plantations to explore the dynamics of nutrient concentration and microbial community composition. The aim of this study was to provide insights into nutrient cycling under plantations with different tree species. Our results showed that the initial concentrations of phosphorus (P) and potassium (K) were significantly higher in the fine root of M. laosensis than those in C. lanceolata, which significantly decreased with decomposition. Nitrogen (N) concentration in fine roots of both species increased with decay time. The variation of N concentration in fine root of C. lanceolata lagged behind that in M. laosensis. During the decomposition, magnesium (Mg) concentration in fine root of C. lanceolata showed no significant changes, but that of M. laosensis decreased at the initial decay stage and increased thereafter and was significantly lower than that of C. lanceolata at the 8th month. The ratio of fungi to bacteria (F/B) of both species decreased at the initial stage and then increased, with significantly higher F/B in fine root of M. laosensis than that of C. lanceolate after one-year decay. Redundancy analysis (RDA) showed that changes in N and K concentrations and C/N ratio explained 37.2%, 14.5% and 14.8% of the variations in microbial community composition of C. lanceolata fine root respectively. However, during the decay of M. laosensis fine root, concentrations of Mg and K were key factors, accounting for 35.9% and 17.6% of the variations in microbial community composition, respectively. We concluded that other nutrients beyond N, such as Mg, might also be an important factor affecting root decomposition in different tree species.

[Seasonal dynamics of soil mineral nitrogen pools and nitrogen mineralization rate in different forests in subtropical China]. / 亚热带不同林分土壤矿质氮库及氮矿化速率的季节动态.

We conducted an in situ incubation experiment to determine soil mineral N (NH4+-N and NO3--N) concentrations and soil net N mineralization rates (net ammonification rate and net nitrification rate) using close-top PVC tubes in three adjacent forests (natural forest, Castanopsis kawakamii and Cunninghamia lanceolata plantation) from September 2014 to August 2015 in subtropical China, investigating the effects of forest type and season on soil inorganic N concentrations and soil net N mineralization rates. Results showed that soil NO3--N was the dominant form in mi-neral N pool in all three forests, and the proportion of NO3--N to soil inorganic N content ranged from 55.1% to 87.5% and from 56.1% to 79.1% in natural forest and Cunninghamia lanceolata plantation, respectively. The effects of forest types on soil mineral N pool were only significant on soil NO3--N, and the concentration of NO3--N in Castanopsis kawakamii was significantly lower than in the other two forests. The NO3--N and mineral N pool varied seasonally in all forests, and were higher in dormant season (October to February) than in growing season (March to September). Soil nitrification rate was very low in the whole year in all three forests and soil net ammonification was the major process of soil net mineralization. Tree species significantly affected soil net ammonification rate, and the value under Chinese fir was significantly lower than the other two fore-sts. The seasonal patterns of the soil net ammonification rate were not similar in all the three forests, but with the lowest value occurring in November and February in the following year. Analysis using variance of repeated measures indicated that soil mineral N concentrations and soil N mineralization rates were significantly affected by forest type and season, and correlation analysis showed that soil mineral N and soil N mineralization rate were significantly affected by water moisture and temperature, and the effects of litter on soil N mineralization rate were mainly through quality control, ra-ther than the quantity control.

[Effects of litter and root exclusion on soil microbial community composition and function of four plantations in subtropical sandy coastal plain area, China]. / å‡‹è½ç‰©å’Œæ ¹ç³»åŽ»é™¤å¯¹æ»¨æµ·æ²™åœ°åœŸå£¤å¾®ç”Ÿç‰©ç¾¤è½ç»„æˆå’ŒåŠŸèƒ½çš„å½±å“.

We conducted detritus input and removal treatment (DIRT) to examine the effects of shifting above- and belowground carbon (C) inputs on soil microbial biomass, community composition and function in subtropical Pinus elliottii, Eucalyptus urophylla × Eucalyptus grandis, Acacia aulacocarpa and Casuarina equisetifolia coastal sandy plain forests, and the treatments included: root trenching, litter removal and control. Up to September 2015, one year after the experiment began, we collected the 0-10 cm soil samples from each plot. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community composition, and micro-hole enzymatic detection technology was utilized to determine the activity of six kinds of soil enzymes. Results showed that changes in microbial biomass induced by the C input manipulations differed among tree species, and mainly affected by litter and root qualily. In E. urophylla × E. grandis stands, root trenching significantly decreased the contents of total PLFAs, Gram-positive bacteria, Gram-negative bacteria, fungi and actinomycetes by 31%, 30%, 32%, 36% and 26%, respectively. Litter removal reduced the contents of Gram-positive bacteria, fungi and actinomycetes by 24%, 27% and 24%, respectively. However, C input manipulations had no significant effect on soil microbial biomassunder other three plantations. According to the effect of C input manipulations on soil microbial community structure, litter and root exclusion decreased fungi abundance and increased actinomycetes abundance. Different treatments under different plantations resulted in various soil enzyme activities. Litter removal significantly decreased the activities of cellobiohydrolase, ß-glucosidase, acid phosphatase and N-acetyl-ß-d-glucosaminidase of P. elliottii, A. aulacocarpa and C. equisetifolia, root exclusion only decreased and increased the activities of ß-glucosidase in P. elliottii and A. aulacocarpa forest soils, respectively. Litter removal also decreased the activities of polyphenol oxidase (PPO) and peroxidase (PER) in P. elliottii and C. equisetifolia forest soils, while root trenching had no significant effect on the activities of PPO and PER under all plantations. The properties of litter and root were the important factors in determining the soil microbial community and enzyme activity, and the change of soil microenvironment, such as temperature and moisture, caused by C input manipulations was also the important driver for the change of soil microbial property.

[Effects of forest types on soil dissolved organic carbon and nitrogen in surface and deep la-yers in subtropical region, China.] / äºšçƒ­å¸¦å ¸åž‹æž—åˆ†å¯¹è¡¨å±‚å’Œæ·±å±‚åœŸå£¤å¯æº¶æ€§æœ‰æœºç¢³ã€æ°®çš„å½±å“.

Forest types have significant effects on the availability and dynamics of soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). By now the impacts of forest types on soil DOC and DON were mainly focused on surface soil (0-10 cm). Based on the comparisons between natural forest, Phyllostachys pubescens, Castanopsis kawakamii and Cunninghamia lanceolata plantations, we investigated the effects of forest types on soil DOC and DON pools in top (0-10 cm) and deep soils (40-60 cm). Cold water, hot water and KCl solutions were used to extract soil DOC and DON from surface and deep soils. Results showed that the effects of forest types on soil DOC, DOC/TOC, DON and soil microbial biomass carbon were only significant in the surface soil. The concentrations of DOC and DON varied with extract methods and hot water extracted the largest amounts of DOC and DON, and cold water the least. Correlations among hot water, KCl and cold water extracted DOC and DON were significant, suggesting that the organic C and N released by these three solutions might be at least partly from similar pools. The concentrations of DOC and DON and DOC/TOC in surface soil under natural forest and P. pubescens were greater than under C. kawakamii and C. lanceolata. It indicated that the concentrations of DOC and DON were greater under the natural forest and P. pubescens than under the C. kawakamii and C. Lanceolata, and more beneficial to improve soil fertility.

[Effects of tree species transfer on soil dissolved organic matter pools in a reforested Chinese fir (Cunninghamia lanceolata) woodland].

Based on the comparison between reforested 19-year-old Mytilaria laosensis and Cunninghamia lanceolata plantations on cut-over land of C. lanceolata, effects of tree species transfer on soil dissolved organic matter were investigated. Cold water, hot water and 2 mol x L(-1) KCl solution were used to extract soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from 0-5, 5-10 and 10-20 cm soil layers. In M. laosensis plantaion, the concentrations of soil DOC extracted by cold water, hot water and 2 mol L(-1) KCl solutions were significantly higher than that in C. lanceolata plantation. In the 0-5 and 5-10 cm layers, the concentrations of soil DON extracted by cold water and hot water in M. laosensis plantation were significantly higher than that in C. lanceolata plantation. The extracted efficiencies for DOC and DON were both in order of KCl solution > hot water > cold water. In the 0-5 cm layers, soil microbial biomass carbon (MBC) under M. laosensis was averagely 76.3% greater than under C. lanceolata. Correlation analysis showed that there were significant positive relationships between hot water extractable organic matter and soil MBC. Differences in the sizes of soil DOC and DON pools between the M. laosensis and C. lanceolata forests might be attributed to the quality and quantity of organic matter input. The transfer from C. lanceolata to M. laosensis could improve soil fertility in the plantation.

[Effects of broadleaf plantation and Chinese fir (Cunninghamia lanceolata) plantation on soil carbon and nitrogen pools].

A comparative study was conducted on the soil C and N pools in a 19-year-old broadleaf plantation and a Chinese fir (Cunninghamia lanceolata) plantation in subtropical China, aimed to understand the effects of tree species on the soil C and N pools. In the broadleaf plantation, the C and N stocks in 0-40 cm soil layer were 99.41 Mg.hm-2 and 6. 18 Mg.hm-2, being 33.1 % and 22. 6 % larger than those in Chinese fir plantation, respectively. The standing biomass and the C and N stocks of forest floor in the broadleaf plantation were 1.60, 1.49, and 1.52 times of those in Chinese fir plantation, respectively, and the differences were statistically significant. There was a significant negative relationship between the forest floor C/N ratio and the soil C and N stocks. In the broadleaf plantation, the fine root biomass in 0-80 cm soil layer was 1.28 times of that in the Chinese fir plantation, and the fine root biomass in 0-10 cm soil layer accounted for 48. 2 % of the total fine root biomass. The C and N stocks in the fine roots in the broadleaf plantation were also higher than those in the Chinese fir plantation. In 0-10 cm soil layer, its C stock had a significant positive relationship with the fine root C stock. It was suggested that as compared with Chinese fir plantation, the soil in broadleaf plantation had a greater potential to accumulate organic carbon.

[Dynamic changes of soil respiration in Citrus reticulata and Castanea henryi orchards in Wanmulin Nature Reserve, Fujian Province of East China].

From January 2009 to December 2009, the soil respiration in the Citrus reticulata and Castanea henryi orchards in Wanmulin Nature Reserve was measured with Li-8100, aimed to characterize the dynamic changes of the soil respiration and its relationships with soil temperature and moisture in the two orchards. The monthly variation of the soil respiration in the orchards was single-peaked, with the peak appeared in July (3.76 micromol x m(-2) x s(-1)) ) and August (2.69 micromol x m(-2) x s(-1)). Soil temperature was the main factor affecting the soil respiration, and explained 73%-86% of the monthly variation of soil respiration. The average annual soil respiration rate was significantly higher in Citrus reticulata orchard than in Castanea henryi orchard, with the mean value being 2.68 and 1.55 micromol x m(-2) x s(-1), respectively. There was a significant positive correlation between the soil respiration rate and soil moisture content in Castanea henryi orchard, but less correlation in Citrus reticulata orchard. The Q10 value of the soil respiration in Citrus reticulata and Castanea henryi orchards was 1.58 and 1.75, and the annual CO2 flux was 10.01 and 5.77 t C x hm(-2) x a(-1), respectively.

Ten-year survey on oncology publications from China and other top-ranking countries.

BACKGROUND: Cancer is a global disease that knows no borders. Over the past decade, oncology research had developed rapidly worldwide. The aim of this study was to evaluate the publication characteristics in oncology journals from China and other top-ranking countries. METHODS: The present study was designed to study publication characteristics in oncology journals from China and other top-ranking countries, the United States (USA), Japan, Germany, the United Kingdom (UK) and France, from 2001 to 2010. We also examined the research output from the three different regions of China: the mainland of China, Hong Kong and Taiwan. RESULTS: Articles published in 163 journals related to oncology were retrieved from the PubMed database. The number of articles showed significantly positive trends for the six countries. The percentage of articles in the world output showed a significantly positive increase in contributions from China, especially the mainland of China. China contributed 4.5% of the total 163 journals, and 2.5% of the journals with the top 10% impact factor (IF) scores. USA contributed 31.4% of the total world output, 40.5% of the top 10% IF score journals and ranked the first. CONCLUSIONS: This analysis described the research output from each country and region of China, and revealed the positive trend in China during 2001 and 2010. Also, by contrast with other top-ranking countries, these results imply that China falls behind the others in conducting high-quality oncology research.

Application of gene sequencing directly to identify the pathogens in specimens.

BACKGROUND: Accurate identification of bacterial isolates is an essential task in clinical microbiology. This study compared culturing to analyzing 16S rRNA gene sequences as methods to identify bacteria in clinical samples. We developed a key technique to directly identify bacteria in clinical samples via nucleic acid sequences, thus improving the ability to confirm pathogens. METHODS: We obtained 225 samples from Beijing Tongren Hospital and examined them by conventional culture and 16S rDNA sequencing to identify pathogens. This study made use of a modified sample pre-treatment technique which came from our laboratory to extract DNA. 16S rDNA was amplified by PCR. The amplified product was sequenced on a CEQ8000 capillary sequencer. Sequences were uploaded to the GenBank BLAST database for comparison. RESULTS: Among the positively cultivated bacterial strains, seven strains were identified differently by Vitek32 and by 16S rDNA sequencing. Twelve samples that were negative by standard culturing were determined to have pathogens by sequence analysis. CONCLUSION: The use of 16S rRNA gene sequencing can improve clinical microbiology by providing better identification of unidentified bacteria or providing reference identification of unusual strains.

[Relationship between copper injury and apoptosis and the effect of curcumin on copper-injured BRL cells].

OBJECTIVE: To study the relationship between copper-induced apoptosis and reactive oxygen species (ROS) in BRL cells and the effect of curcumin, a plant-derived polyphenol, on copper-injured BRL cells. METHODS: BRL cells were treated with CuSO4 (100 micromol/L) or curcumin + CuSO4. The BRL cells without any treatment were used as controls. Flow cytometry was applied to detect the production of ROS with fluorescent probe DCFH-DA. MTT colorimetry was used to evaluate cell activity. Apoptosis was measured using Hoechst 33258 staining and Annexin V-FITC and propidiumiodide (PI) staining. JNK/SAPK protein level was detected using Western blot. RESULTS: ROS levels (711.70 +/- 68.33 vs 87.22 +/- 7.58) and apoptosis rate (45.08 +/- 1.87% vs 8.23 +/- 2.56%) of BRL cells reached to a peak after 6 hrs of CuSO4 treatment, which were significantly higher than controls (P < 0.01). JNK/SAPK levels increased significantly after 6 hrs of CuSO4 treatment and peaked at 24 hrs of CuSO4 treatment compared with controls (P < 0.01). Curcumin pretreatment decreased significantly ROS and JNK/SAPK levels as well as the apoptosis rate when compared with the CuSO4-treated alone group (P < 0.01). CONCLUSIONS: Copper may induce apoptosis of BRL cells. ROS participated in apoptosis induced by copper. Curcumin produced protections on copper-injured BRL cells possibly by anti-oxidation and inhibition of p-JNK expression.

[Curcumin attenuated the lipid peroxidation and apoptotic liver injury in copper-overloaded rats].

OBJECTIVE: Hepatolenticular degeneration (Wilson disease, WD) is an autosomal recessive disorder of copper metabolism. The clinical manifestations are dominated by the neuropsychiatric and hepatic symptoms due to copper deposition. Investigation of mechanism of copper injury should be helpful for elucidating the pathogenesis and treatment of WD. Curcumin, a plant-derived polyphenol, exhibits the properties of anti-oxidant, anti-inflammation and has no evident side effects, therefore, today curcumin is studied by more and more researchers in pharmacologic action and clinical application especially for its protective effect on liver diseases. The present study was designed to investigate the lipid peroxidation and apoptotic liver injury in copper-overloaded rats, and to explore the protective effects of curcumin. METHODS: Wistar rats, male, were randomly divided by copper-overloaded groups and curcumin treatment groups and control group. Copper-overloaded rat model was established by feeding with forage containing 1 g/kg copper sulfate and water with 0.185% copper sulfate for 8 weeks or 12 weeks. In the treatment groups, curcumin was administered orally either 50 mg/kg or 200 mg/kg for 2 weeks and 4 weeks and 8 weeks and fed with copper sulfate at the same time until the 12th week. Malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) in liver homogenates were measured to reflect the copper induced lipid peroxidation. The apoptosis of liver cell was detected by electron microscope (EM) and TUNEL assay. The expressions of TNF-alpha mRNA and IL-8 mRNA were observed by RT-PCR. Contents of TNF-alpha and IL-8 in liver homogenates were measured by ELISA. RESULTS: The MDA concentrations were significantly increased and the GSH and SOD levels were decreased in the copper-overloaded rats. The apoptosis index displayed from (2.2 +/- 1.2)% in control rats to (16.7 +/- 2.5)% in the copper treated animals. Expression of TNF-alpha mRNA and IL-8 mRNA were enhanced in the copper-overloaded rats. Curcumin significantly attenuated the increase of MDA concentrations and recovered the GSH and SOD levels. The apoptosis index decreased to (10.4 +/- 1.2)% in the copper-overloaded rats with curcumin treatment. Curcumin down-regulated the expressions of TNF-alpha mRNA and IL-8 mRNA and content of TNF-alpha and IL-8. Histological changes induced by copper in liver, such as mitochondrial swelling and endoplasmic reticulum distention and increased lysosomal granules in the model rats, were also improved significantly by curcumin treatment as evidenced by EM examination. CONCLUSION: Copper-overloading caused lipid peroxidatic injury and induced significant apoptosis in liver. TNF-alpha and IL-8 might be involved in liver injury in this model. Curcumin exhibited protective effects and possibly acted through its antioxidant and anti-apoptotic properties.