Interposition of acellular amniotic membrane at the tendon to bone interface would be better for healing than overlaying above the tendon to bone junction in the repair of rotator cuff injury.

PURPOSE: The retear rate of rotator cuff (RC) after surgery is high, and the rapid and functional enthesis regeneration remains a challenge. Whether acellular amniotic membrane (AAM) helps to promote the healing of tendon to bone and which treatment is better are both unclear. The study aims to investigate the effect of AAM on the healing of RC and the best treatment for RC repair. METHODS: Thirty-three Sprague Dawley rats underwent RC transection and repair using microsurgical techniques and were randomly divided into the suturing repair only (SRO) group (n = 11), the AAM overlaying (AOL) group (n = 11), and the AAM interposition (AIP) group (n = 11), respectively. Rats were sacrificed at 4 weeks, then examined by subsequent micro-CT, and evaluated by histologic and biomechanical tests. The statistical analyses of one-way ANOVA or Kruskal-Wallis test were performed using with SPSS 23.0. A p < 0.05 was considered a significant difference. RESULTS: AAM being intervened between tendon and bone (AIP group) or overlaid over tendon to bone junction (AOL group) in a rat model, promoted enthesis regeneration, increased new bone and cartilage generation, and improved collagen arrangement and biomechanical properties in comparison with suturing repair only (SRO group) (AOL vs. SRO, p < 0.001, p = 0.004, p = 0.003; AIP vs. SRO, p < 0.001, p < 0.001, p < 0.001). Compared with the AOL group, the AIP group had better results in micro-CT evaluation, histological score, and biomechanical testing (p = 0 0.039, p = 0.011, p = 0.003, respectively). CONCLUSION: In the RC repair model, AAM enhanced regeneration of the tendon to bone junction. This regeneration was more effective when the AAM was intervened at the tendon to bone interface than overlaid above the tendon to bone junction.

At-Home COVID-19 Rapid Antigen Test Down to 0.03 pg mL-1 of Nucleocapsid Protein.

Rapid and ultra-sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for early screening and management of COVID-19. Currently, the real-time reverse transcription polymerase chain reaction (rRT-PCR) is the primary laboratory method for diagnosing SARS-CoV-2. It is not suitable for at-home COVID-19 diagnostic test due to the long operating time, specific equipment, and professional procedures. Here an all-printed photonic crystal (PC) microarray with portable device for at-home COVID-19 rapid antigen test is reported. The fluorescence-enhanced effect of PC amplifies the fluorescence intensity of the labeled probe, achieving detection of nucleocapsid (N-) protein down to 0.03 pg mL-1 . A portable fluorescence intensity measurement instrument gives the result (negative or positive) by the color of the indicator within 5 s after inserting the reacted PC microarray test card. The N protein in inactivated virus samples (with cycle threshold values of 26.6-40.0) can be detected. The PC microarray provides a general and easy-to-use method for the timely monitoring and eventual control of the global coronavirus pandemic.

Editorial Commentary: The Indication and Technique of Iliotibial Band Release for External Snapping Hip During Hip Arthroscopy in Patients With Femoroacetabular Impingement Syndrome.

Patients with femoroacetabular impingement syndrome (FAIS) often have extra-articular disorders, such as external snapping hip (ESH). We recommend that obvious ESH be addressed by endoscopic transversal iliotibial band (ITB) release during hip arthroscopy for FAIS because the residual serious snapping caused by ESH negatively affects the outcome of hip arthroscopy. However, for mild ESH without indications for severe trochanteric bursitis on magnetic resonance imaging, we still propose that physical therapy, extracorporeal shock wave therapy, or local injection be performed for pain relief. Surgical interventions for ESH including the Z-plasty technique and the modified Z-plasty technique for lengthening the ITB, as well as endoscopic cruciate or transversal incision in the ITB for release, have been reported with good results. Every technique has advantages and disadvantages, and we believe that surgeons should perform ITB release for ESH at the time of hip arthroscopy for FAIS based on their personal experience and inclination. In any case, excessive release of the ITB should be avoided. Finally, we wish to propose that more attention should be paid to the peri-greater trochanter (GT) space, an anatomic space between the ITB and the GT, which is similar to the subacromial space in the shoulder joint. Greater trochanteric pain syndrome (GTPS), related to the peri-GT space, is a spectrum of disorders, including trochanteric bursitis, abductor tendon pathology, and ESH. Precise diagnosis and proper procedures for concurrent GTPS during surgery may improve the outcome of arthroscopy in patients with both FAIS and GTPS.

Endoscopic Iliotibial Band Release During Hip Arthroscopy for Femoroacetabular Impingement Syndrome and External Snapping Hip Had Better Patient-Reported Outcomes: A Retrospective Comparative Study.

PURPOSE: To compare patient-reported outcomes (PROs) in patients with femoroacetabular impingement (FAI) syndrome and external snapping hip (ESH) treated with hip arthroscopy with or without endoscopic iliotibial band (ITB) release. METHODS: Retrospective review case series with both FAI syndrome and ESH who underwent surgical treatment under same indications. According to the primary operation that was determined by patients themselves, the patients undergoing ITB release during hip arthroscopy for FAI syndrome were enrolled in the ITB-R group, and patients undergoing hip arthroscopy without ITB release were enrolled in non-ITB-R group. Patients with dysplasia, severe osteoarthritis, revision, and bilateral surgery were excluded. PROs including international Hip Outcome Tool (iHOT-33), modified Harris Hip Score (mHHS), visual analog scale for pain (VAS-pain) and VAS-satisfaction, and the rates of achieving minimal clinically important difference, patient acceptable symptomatic state (PASS), and substantial clinical benefit for the PROs at 2 years operatively were comparative analyzed. RESULTS: The prevalence of ESH in patients with FAI syndrome who underwent hip arthroscopy in our institution was 4.9% (30 of 612 hips). The mean age at the time of surgery was 33.1 ± 6.9 years (range 22-48 years). After exclusion, 16 patients (16 hips) were enrolled into ITB-R group and 11 patients (11 hips) enrolled into non-ITB-R group. PROs including iHOT-33, mHHS, VAS-pain, and VAS-satisfaction in patients in ITB-R group were better than that in non-ITB-R group at 2 years postoperatively (P = .013, .016, .002, and .005, respectively). The rates of achieving PASS for mHHS, PASS for VAS-pain, and substantial clinical benefit for iHOT-33 of patients in ITB-R group were significantly better than that in non-ITB-R group (P = .009, .006, and .027, respectively). CONCLUSIONS: Patients with both FAI syndrome and ESH undergoing ITB release during hip arthroscopy had better PROs than those undergoing hip arthroscopy without ITB release. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

A method for increasing the solubility of industrial azo pigments for 13 C and 1 H NMR spectra and the assignments of their 13 C and 1 H NMR peaks.

A method for increasing the solubilities of industrial azo pigments in DMSO by adding DBU (1,8-diaza-7-bicyclo[5.4.0]undecene) has been developed. This facilitated the acquisition of solution 13 C NMR spectra of the pigments. This method was applied to four types of azo pigments: naphthol AS (3-hydroxy-2-naphthoic acid anilide) pigments, naphthol pigments, pyrazolone pigments and acetoacetanilide pigments. This represents the first solution 13 C NMR spectra for naphthol AS pigments. Altogether 18 industrial azo pigments were analysed using 1D and 2D NMR techniques. The proton and corresponding carbon NMR resonances of these pigments have all been assigned.

A comparative analysis of the efficacy of anterior cruciate ligament reconstruction with autologous ligament grafting at different time points.

BACKGROUND: This study was performed to compare the clinical efficacies of anterior cruciate ligament (ACL) reconstruction with autologous ligament grafting at different time points. METHODS: Eighty-five patients with ACL were categorized into two groups: Group A (GA, n = 45), who underwent early-stage (≤3 weeks) surgery, and Group B (GB, n = 40), who underwent advanced-stage (>3 weeks) surgery. Perioperative conditions, knee joint functions, activity and stability before and at 6 months postoperatively, changes in quality of life (QOL), good and excellent rates of knee joint functions, and incidence of complications were compared between the two groups. RESULTS: In both groups, there was an increase in the International Knee Documentation Committee (IKDC) score, Lysholm score, and QOL and a decrease in the knee joint angle flexion limitation, angle of spread limitation, positive rates in the anterior drawer test (ADT), and Lachman test score (P < .05) after surgery. At 6 months postoperatively, the IKDC score, Lysholm score, and QOL were higher in GA than in GB (P < .05). The good and excellent rates of knee joint functions were higher in GA than in GB (93.33% vs. 77.50%) (P < .05). CONCLUSION: Anterior cruciate ligament reconstruction with autologous ligament grafting can achieve good effects whether performed in the early or advanced stage; however, the improvements in patients' knee joint functions and QOL are better in the early stage. Therefore, early ACL reconstruction with autologous ligament grafting is suggested.

Heat-induced amyloid-like aggregation of ß-lactoglobulin affected by glycation by α-dicarbonyl compounds in a model study.

BACKGROUND: α-Dicarbonyl compounds are widely generated in the Maillard reaction, caramelization and oil oxidation during heat treatment. These compounds can readily react with lysine and arginine residues of a protein, whereas the influence of these compounds on protein structure and quality has seldom been revealed. This study compared influence of glycation by glucose and α-dicarbonyl compounds on amyloid-like aggregation of ß-lactoglobulin (ß-LG), both fibrillation kinetics and conformation of aggregates were studied. RESULTS: Compared with glycation by glucose, the glycation by α-dicarbonyl compounds resulted in faster reduction of free amino group, sulfydryl group, and the relative content of ß-sheet secondary structure, according to the ultraviolet (UV) spectra or circular dichroism (CD) spectra results. Based on the analysis of fibrillation kinetics using thioflavin T (ThT) binding assay, the glycation by α-dicarbonyls were more efficient in suppressing the growth of fibrillar aggregates. In addition, glycation by α-dicarbonyl resulted in amorphous oligomers, which were compared with the amyloid-like aggregates in control and glucose-glycated samples, based on the transmission electron microscopy (TEM) observation. CONCLUSIONS: Glycation by α-dicarbonyl compounds induced larger decline in the ß-sheet structure of ß-LG than glycation by glucose, and thus largely suppressed the amyloid-like aggregation of ß-LG and changed the morphology of aggregates. © 2019 Society of Chemical Industry.

Effect of fermented blueberry on the oxidative stability and volatile molecule profiles of emulsion-type sausage during refrigerated storage.

OBJECTIVE: The aim of this work was to assess the effect of fermented blueberry (2%, 4% and 6%) on the oxidative stability and volatile molecule profiles of emulsion-type sausage stored at 4 °C for 28 days. METHODS: The antioxidant activity of fermented blueberry (FB) was determined through radical-scavenging activity of 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH) and hydroxyl radicals. Four formulations of sausage treatments with different FB levels (0, 2, 4, 6%) were prepared, then peroxide value (POVs), thiobarbituric acid-reactive substances (TBARS) values, protein carbonyls and thiol groups were measured. The aroma profiles of sausages for each treatments were also determined. RESULTS: The IC50 value indicated that FB had greater scavenging ability than ascorbic acid against DPPH and hydroxyl radicals. Sausages with FB significantly retarded increases in POVs and TBARS, as well as in the content of protein carbonyls during all storage days (p &lt; 0.05). Particularly, 4% and 6% FB-treated sausages had better oxidation inhibition effects. However, FB accelerated the reduction in thiol groupss (p &lt; 0.05). Additionally, FB inhibits the excessive formation of aldehyde compounds; for example, hexanal decreased from 58.25% to 19.41%, which may cause rancid flavors. FB also created 6 alcohols (i.e., 2-methyl-1-propanol, 3-methyl-1-butanol and phenylethyl alcohol), 5 ester compounds (i.e., ethyl acetate, ethyl lactate and ethyl hexanoate) and 3-hydroxy-2-butanone in the sausages that contribute to sausage flavors. The principal component analysis (PCA) showed that the aroma profiles of sausages with and without FB are easily identified. CONCLUSION: The addition of FB could significantly recduce the lipid and protein oxidation and improve oxidative stability for storage. Also, adding FB could inhibit rancid flavors and contribute to sausage flavors.

Influence of salting process on the structure and in vitro digestibility of actomyosin.

Salting process is widely used in the process of meat products, whereas few studies have revealed the digestibility of actomyosin after salting treatment, which is closely related with the nutrition of meat. This work reported effect of salting on the structural change and digestibility of actomyosin before and after heat treatment. Actomyosin in 0.4 M and 0.8 M of NaCl had higher content of disulfide bonds, and actomyosin in 0.4 M NaCl showed the largest particle sizes before and after heat treatment. In addition, actomyosin in 0.6 M and 0.8 M of NaCl was oxidized more severely after heat treatment. Based on peptidomics analysis by using liquid chromatography tandem mass spectrometry (LC-MS/MS), actomyosin in 0.6 M was digested more easily, which was followed by sample in 0.8 M and 0.4 M of NaCl in descending order. The lowest digestibility of actomyosin in 0.4 M NaCl was related with its higher content of disulfide bond and severer aggregation behavior. The lower digestibility of actomyosin in 0.8 M NaCl should be related with the higher content of disulfide bonds and surface oxidation. These results highlight the crucial role of salting process in affecting the digestibility of meat protein.

Interplay between Residual Protease Activity in Commercial Lactases and the Subsequent Digestibility of ß-Casein in a Model System.

One of the conventional ways to produce lactose-hydrolyzed (LH) milk is via the addition of commercial lactases into heat-treated milk in which lactose is hydrolyzed throughout storage. This post-hydrolysis method can induce proteolysis in milk proteins due to protease impurities remaining in commercial lactase preparations. In this work, the interplay between lactose hydrolysis, proteolysis, and glycation was studied in a model system of purified ß-casein (ß-CN), lactose, and lactases using peptidomic methods. With a lactase presence, the proteolysis of ß-CN was found to be increased during storage. The protease side-activities mainly acted on the hydrophobic C-terminus of ß-CN at Ala, Pro, Ile, Phe, Leu, Lys, Gln, and Tyr positions, resulting in the formation of peptides, some of which were N-terminal glycated or potentially bitter. The proteolysis in ß-CN incubated with a lactase was shown to act as a kind of "pre-digestion", thus increasing the subsequent in vitro digestibility of ß-CN and drastically changing the peptide profiles of the in vitro digests. This model study provides a better understanding of how the residual proteases in commercial lactase preparations affect the quality and nutritional aspects of ß-CN itself and could be related to its behavior in LH milk.

Influence of hydrothermal treatment on the structural and digestive changes of actomyosin.

BACKGROUND: Heat treatment induces both structural and digestive change of meat protein. However, little has been revealed regarding the associations between structural changes and digested peptides of myofibrillar proteins. This work investigated the effects of heat treatment on the structures and in vitro digestibility of actomyosin, and the peptidomics of the digests were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). RESULTS: Heat treatment resulted in unfolding and aggregation behavior of actomyosin according to the results of surface hydrophobicity and particle size. Formation of disulfide bonds and increase in carbonyl groups that occurred during heat treatment of actomyosin indicated the oxidation of specific residues. Unfolding behavior could elevate digestibility of actomyosin by exposing residues, based on the identification of peptides in digests of actomyosin using LC-MS/MS. However, the disulfide bond proved to reduce the action of digestive proteases, since the peptides number (increased from 56 to 86 in sample heated at 70 °C for 30 min) and peptides intensity in digests largely increased after the addition of dithiothreitol (DTT). Heating at higher temperature (100 °C) induced severer aggregation and oxidation, which resulted in lower digestibility of actomyosin than that heated at 70 °C by burying or damaging partial cleavage sites for digestive proteases. CONCLUSIONS: This work highlights the huge influence of heat treatment on the multi-scale structures of myofibrillar proteins, which largely changed the peptides composition in protein digests. © 2019 Society of Chemical Industry.

Androsterone-based gels enable diastereospecific reductions and diastereoselective epoxidations of gelators.

Eleven new androsterone-based gelators were synthesized, and their gelation properties and gel-mediated reactions were investigated. The relationships between the structures, gelation and self-assembly processes of the gelators are discussed. By using granular PTFE (polytetrafluoroethylene) as costirrers, quantitative and diastereospecific reductions of the gelator carbonyl groups mediated by water were achieved in the gels of seven gelators. This reduction did not occur in the control experiment which used organic solvent-mediated conventional conditions. The diastereospecific and quantitative reductions possibly occur via a hydrogen-bonded-activated carbonyl mechanism. Five of the gelators underwent gel-mediated epoxidation and the products were more diastereoselective than those obtained using conventional epoxidation reactions. This can be attributed to the ordered arrangements in the gels.

Comparison of Arthroscopic and Conservative Treatments for Knee Osteoarthritis: A 5-Year Retrospective Comparative Study.

PURPOSE: To compare the effectiveness of arthroscopic and conservative treatments in patients with knee osteoarthritis (KOA) with 5 years of follow-up. METHODS: Patients diagnosed with Kellgren-Lawrence grade 2 to 4 KOA who underwent arthroscopic or conservative treatment from May 2005 to May 2012 were included. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score was collected 1, 2, 3, 4, and 5 years after the initial treatment, and the number of patients who underwent total knee arthroplasty (TKA) at every time point was recorded. RESULTS: Three hundred eighty-two patients (168 in the conservative group and 214 in the arthroscopy group) were included. Five years after the initial treatment, 32 of the 214 patients who underwent arthroscopy (15.0%) compared with 30 of the 168 patients in the conservative treatment group (17.9%) ultimately underwent TKA, with no statistically significant difference between groups (P = .20). The WOMAC score was significantly lower in the arthroscopy group than in the conservative group at year 1 (24.33 ± 21.56 vs 36.43 ± 16.22, respectively) and year 2 (26.31 ± 17.84 vs 35.41 ± 19.21, respectively). There were no significant between-group differences at years 3, 4, and 5. CONCLUSIONS: Compared with conservative treatment, arthroscopy provided no benefit in decreasing or delaying arthroplasty surgery. However, arthroscopy had a greater ability to relieve symptoms at 1 and 2 years. Our results suggest that arthroscopy can relieve symptoms up to 2 years without elevating the risk of arthroplasty. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

The effect of cooking temperature on the aggregation and digestion rate of myofibrillar proteins in Jinhua ham.

BACKGROUND: In order to evaluate the effect of cooking temperature on the nutrition quality of dry-cured hams, 60 biceps femoris samples from 16 Jinhua hams were divided into four groups (control, 70, 100 and 120 °C) and cooked for 30 min. Carbonyl content, sulfhydryl groups, surface hydrophobicity, microstructure, protein aggregation and digestibility of myofibrillar proteins were investigated. RESULTS: Cooking promoted carbonylation and decreased sulfhydryl groups in a temperature-dependent way. Scanning electron microscopy and Nile Red revealed that protein aggregation became a main phenomenon at 120 °C; it coincided with surface hydrophobicity. The increased carbonyl content and decreased sulfhydryl groups contributed to the formation of aggregates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles showed the initial difference in proteolysis rate among four groups. The in vitro digestibility of pepsin and of trypsin and α-chymotrypsin increased from the control to 100 °C and decreased from 100 to 120 °C. CONCLUSION: The increased digestibility could be attributed to the oxidation of proteins and exposing recognition sites of digestive enzymes, while the decreased digestibility was due to the formation of aggregates. Cooking was a main factor that affected the digestibility of Jinhua ham, and cooking at 100 °C could be an ideal way to gain the highest digestibility of Jinhua ham. © 2018 Society of Chemical Industry.

Near-infrared fluorescent dyes with large Stokes shifts: light generation in BODIPYs undergoing excited state intramolecular proton transfer.

Novel BODIPYs undergoing excited state intramolecular proton transfer are reported. The molecules afford NIR emission with a large Stokes shift and possess a free hydroxyl unit that is easy to functionalize, allowing the dyes to be exploited as a valuable scaffold in probe design.

Dietary Proteins Rapidly Altered the Microbial Composition in Rat Caecum.

Dietary proteins can alter gut microbial diversity. However, little is known about how gut bacteria respond to dietary proteins during short-term feeding. In the present study, PCR-DGGE analysis was performed to compare changes in gut microbial composition in rat caecum after rats were fed proteins from soy, pork, beef, chicken, fish and casein (control) for 2, 7 and 14 days. On day 2, differences were observed in microbial composition between groups of red meat (pork and beef) and white meat (chicken and fish) proteins. For a certain diet group, microbial composition showed a great change with feeding time. Principle component analysis indicated that the soy protein group showed a good separation in microbial composition from the casein and meat protein groups on days 7 and 14.

Novel anatomical reconstruction of distal tibiofibular ligaments restores syndesmotic biomechanics.

PURPOSE: To date, there is a paucity of literature on syndesmotic reconstruction techniques that restore both anatomic stability and physiologic syndesmotic biomechanics. In this cadaveric study, (1) a novel syndesmotic reconstruction surgical technique using autogenous peroneus brevis tendon was described and (2) the biomechanical properties of the reconstruction was investigated. METHODS: Ten fresh-frozen lower extremities were used in this study. Reconstruction of the anterior and posterior, as well as the interosseous tibiofibular ligaments was performed with a halved peroneus brevis tendon. Biomechanics were assessed using foot external rotation torque and ankle dorsiflexion axial loading tests, which were performed in (a) intact, (b) cut, (c) anatomically reconstructed syndesmotic ligaments, and (d) 3.5 mm tricortical syndesmotic screw fixation. Medial-lateral and anterior-posterior displacements of the distal fibula were recorded during foot external rotation and fibular axial displacement was recorded during ankle axial loading. RESULTS: The fibula was displaced posteriorly and proximally with respect to the tibia in all specimens during external rotation and axial loading tests, respectively. Significant differences (p < 0.05) were found in distal fibular displacements between anatomically reconstructed ligaments and screw fixation. Tricortical syndesmotic screw fixation resulted in 59% of posterior fibular displacement when compared to intact ligaments. No significant differences (n.s.) in distal fibular displacement were demonstrated between intact ligaments and anatomically reconstructed ligaments. CONCLUSION: Anatomical reconstruction of the distal tibiofibular ligaments with the peroneus brevis tendon provides stability and recreates the biomechanical properties of an intact syndesmosis. This new surgical technique may be a viable alternative for the treatment of syndesmotic injuries. LEVEL OF EVIDENCE: V.

Comparative Proteomics Provides Insights into Metabolic Responses in Rat Liver to Isolated Soy and Meat Proteins.

It has been reported that isolated dietary soy and meat proteins have distinct effects on physiology and liver gene expression, but the impact on protein expression responses are unknown. Because these may differ from gene expression responses, we investigated dietary protein-induced changes in liver proteome. Rats were fed for 1 week semisynthetic diets that differed only regarding protein source; casein (reference) was fully replaced by isolated soy, chicken, fish, or pork protein. Changes in liver proteome were measured by iTRAQ labeling and LC-ESI-MS/MS. A robust set totaling 1437 unique proteins was identified and subjected to differential protein analysis and biological interpretation. Compared with casein, all other protein sources reduced the abundance of proteins involved in fatty acid metabolism and Pparα signaling pathway. All dietary proteins, except chicken, increased oxidoreductive transformation reactions but reduced energy and essential amino acid metabolic pathways. Only soy protein increased the metabolism of sulfur-containing and nonessential amino acids. Soy and fish proteins increased translation and mRNA processing, whereas only chicken protein increased TCA cycle but reduced immune responses. These findings were partially in line with previously reported transcriptome results. This study further shows the distinct effects of soy and meat proteins on liver metabolism in rats.

The gut microbiota in young and middle-aged rats showed different responses to chicken protein in their diet.

BACKGROUND: Meat protein in the diet has been shown to be beneficial for the growth of Lactobacillus in the caecum of growing rats; however, it is unknown whether gut microbiota in middle-aged animals have the same responses to meat protein diets. This study compared the composition of the gut microbiota between young and middle-aged rats after being fed 17.7% chicken protein diet for 14 days. METHODS: Feces were collected on day 0 and day 14 from young rats (4 weeks old) and middle-aged rats (64 weeks old) fed with 17.7% chicken protein diets. The composition of the gut bacteria was analyzed by sequencing the V4-V5 region of the 16S ribosomal RNA gene. RESULTS: The results showed that the composition of the gut microbiota was significantly different between young and middle-aged rats on both day 0 and day 14. The percentage of Firmicutes decreased for middle-aged rats (72.1% versus 58.1% for day 0 and day 14, respectively) but increased for young rats (41.5 versus 57.7% for day 0 and day 14, respectively). The percentage of Bacteroidetes increased to 31.2% (20.5% on day 0) for middle-aged rats and decreased to 29.6% (41.3% on day 0) for young rats. The relative abundance of the beneficial genus Lactobacillus increased in response to the intake of chicken protein in the young group, while it had the opposite effect in the middle-aged group. CONCLUSION: The results of our study demonstrated that 17.7% chicken protein diet promoted the beneficial genus Lactobacillus in young rats, but the opposite effect were found in the middle-aged group. To evaluate the linkage between diet and host health, age effect should be considered in the future studies.

Meat proteins had different effects on oligopeptide transporter PEPT1 in the small intestine of young rats.

The peptide transporter 1 (PEPT1) in the apical membrane of enterocytes is the central mechanism for regulating the absorption of di- and tripeptides. Dietary proteins may affect PEPT1 abundance and peptide absorption. The present study aimed to characterize changes in PEPT1 mRNA and PEPT1 protein levels in the duodenum and jejunum of young rats after 7-day diet intervention with casein (reference), soy, beef, pork, chicken and fish proteins and further evaluate the impact on the epithelial absorption capacity. RT-PCR and western blot analyses showed that: (1) PEPT1 protein level in duodenum was higher (p < 0.05) for soy protein group than that for casein group. However, no difference was observed in jejunal PEPT1 protein level between any two diet groups (p > 0.05). The soy protein group had lower crypt depth and higher V/C ratio in the jejunum (p < 0.05). (2) PEPT1 mRNA levels were lower (p < 0.05) in rat duodenum and jejunum in pork, chicken and fish protein groups, whose trend was contrary to the results of jejunual histological observation with lower crypt depth, greater villus height and higher V/C ratio. In conclusion, different meat proteins alter distinct PEPT1 expression level and absorption capacity as reflected by gut morphology in small intestine.