Microstructural changes of cartilage and subchondral bone in a guinea pig model of early- and middle-stage patellofemoral arthritis.

OBJECTIVE: Patellofemoral arthritis is a common type of knee osteoarthritis and a prime cause of anterior knee pain and disability. Most of the existing research on knee osteoarthritis focuses on tibial-femoral arthritis, while studies on patellofemoral arthritis are relatively rare. This study aims to observe changes in osteochondral and subchondral bone structure over time in the patella and femoral trochlea in an animal model of spontaneous patellofemoral arthritis. METHODS: A total of 24 1-, 3- or 5-month-old healthy female Hartley guinea pigs were used for experiments. No intervention was applied, and the mechanical pain threshold was assessed prior to euthanasia. Bilateral knee joints were collected in the animals at the different ages, and the patellofemoral joints were taken to evaluate the bone microstructure of patellofemoral articular cartilage and subchondral bone by macroscopy, histopathology and micro-computed tomography (micro-CT). RESULTS: There was a significant difference in the severity of femoral trochlea injury assessed by the Macro score between 5- and 1-month-old groups (P<0.01), as well as in patellar cartilage damage (P<0.05). The mechanical pain threshold of lower extremities in each group was statistically different between different age groups (P<0.05). The OARSI articular cartilage histopathological scores, including patella and femoral trochlea, were significantly different among 1-, 3- and 5-month-old groups. The 5-month-old group exhibited statistically lower values of bone volume/trabecular volume, trabecular number and trabecular thickness in the femoral subchondral bone and evidently higher structure model index than the 1-month-old group. CONCLUSIONS: This study demonstrated that 3- to 5-month-old female Hartley guinea pigs can develop early-to-mid-stage spontaneous patellofemoral arthritis that causes significant cartilage degeneration and loss of subchondral bone. In addition, the bone microarchitecture of the femur is more severely degraded.

LncRNA nuclear receptor subfamily 2 group F member 1 antisense RNA 1 (NR2F1-AS1) aggravates nucleus pulposus cell apoptosis and extracellular matrix degradation.

Emerging reports uncover that long noncoding RNAs (lncRNAs) help regulate intervertebral disc degeneration (IVDD). Here, we probe the function of lncRNA nuclear receptor subfamily 2 group F member 1 antisense RNA 1 (NR2F1-AS1) in IVDD. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was applied to verify the expression of NR2F1-AS1 and miR-145-5p in nucleus pulposus (NP) tissues from IVDD patients or NP cells dealt with IL-1ß or TNF-α. Flow cytometry or the TdT-mediated dUTP nick end labeling (TUNEL) assay was performed to validate the apoptosis of NP cells with selective regulation of NR2F1-AS1 and miR-145-5p. ECM-related genes, FOXO1, Bax, and Bcl2 were evaluated by qRT-PCR or Western blot (WB). The targeted relationships between NR2F1-AS1 and miR-145-5p, miR-145-5p and FOXO1 were testified by the dual-luciferase reporter assay and the RNA immunoprecipitation (RIP) assay. Our outcomes substantiated that NR2F1-AS1 was up-regulated, while miR-145-5p was down-regulated in intervertebral disc tissues of IVDD patients or NP cells treated with IL-1ß or TNF-α. Besides, overexpressing NR2F1-AS1 intensified ECM degradation and NP cell apoptosis induced by IL-1ß, while knocking down NR2F1-AS1 or up-regulating miR-145-5p reversed IL-1ß-mediated effects in NP cells. Meanwhile, NR2F1-AS1 choked miR-145-5p and abated its effects in NP cells. This study confirms that NR2F1-AS1 modulates IVDD progression by up-regulating the FOXO1 pathway through the sponge of miR-145-5p as a competitive endogenous RNA (ceRNA).

Use of mature compost as filter media and the effect of packing depth on hydrogen sulfide removal from composting exhaust gases by biofiltration.

A study was conducted to investigate the utilization of mature compost as a biofilter medium for the removal of hydrogen sulfide (H2S) from the exhaust gases of the composting process. Source-selected kitchen waste from municipal solid waste was composted in a reactor, and the exhaust gas was passed through a biofilter packed with a 1:4 (wet weight) mixture of mature compost and sand. Two treatments were applied under sterilized and unsterilized conditions to quantify the contribution of microbial activity. The effect of packing depth on H2S removal efficiency was also studied. A global H2S removal efficiency of 51% was obtained in the biofilter for loading rates in the range of 0-429 mg H2S m-3 h-1. The adsorption capacity was the main factor affecting H2S removal efficiency, contributing 64.2% to the total removal efficiency, with microbial activity contributing 35.8%. The relationship between the cumulative amount of H2S removed and the packing height was well-described by a linear equation. The equation indicated that 99% H2S removal efficiency could be achieved using a packing height of 96 cm for unsterilized packing material or 158 cm for sterilized packing material.

Effects of adding bulking agents on biostabilization and drying of municipal solid waste.

The influence of adding a bulking agent on the bio-stabilization and drying of municipal solid waste (MSW) was investigated. Three treatments were considered: the addition of either cornstalks or wood peat to MSW as a bulking agent before bio-drying and a control treatment that contained no bulking agent. Addition of bulking agents to MSW produced less leachate, higher moisture-removal rates, and consumed less volatile solids. Bulking with cornstalks achieved the highest water-removal rate (0.58-0.65kgkg-1). The extent of organic degradation was related to temperature integration during bio-drying. Lipids and cellulose were the main components of organic losses in all treatments and adding a bulking agent changed the sequence and extent of degradation of biochemical components. The bio-drying index values were 1.75, 3.18, and 2.64 for MSW alone, MSW with cornstalks, and MSW with wood peat, respectively. Evaporation heat was the main component of heat consumption, accounting for 58.1-60.7% of the total energy consumption.

Effects of aeration rate on maturity and gaseous emissions during sewage sludge composting.

This study investigated effects of aeration rate (AR) on maturity and gaseous emissions during sewage sludge composting, sewage sludge and corn stalks as the bulking agent were co-composted at different ARs (0.1, 0.2, 0.3L·kg(-1) dry matter (DM)·min(-1)). The thermophilic phase for the low and moderate AR treatments was able meet sanitation requirements, but too short to meet sanitation requirements in the high AR treatment. The high AR treatment was significantly different from the other treatments, and had the lowest electrical conductivity and highest E4/E6(absorbance ratio of wavelength 465 and 665nm). The AR influences the nitrogen variations; high AR compost had the highest NH4(+)-N content and lowest NOx(-)-N content. The AR was the main factor influencing compost stability, but the AR had little impact on pH and the germination index. The moderate AR treatment had the highest NH3 emissions during composting, while the low AR treatment had the highest CH4 and N2O emissions. Based on our comprehensive investigation, the recommended AR for sludge composting is 0.2L·kg(-1) DM·min(-1).