Interaction against different environmental dynamics during a leg extension task is controlled by temporal rather than amplitude scaling of muscular activity

Force exertion against different mechanical environments can affect motor control strategies in order to account for the altered environmental dynamics and to maintain the ability to produce force. Here, we investigated the change of muscular activity of selected muscles of the lower extremities while the participants interacted with an external mechanical device of variable stability. Twenty-five healthy participants exerted force against the device by performing a unilateral ballistic leg extension task under 1 or 3 degrees of freedom (DoF). Directional force data and electromyographic responses from four leg muscles (TA, VM, GM, PL) were recorded. Muscle responses to the altered experimental conditions were analyzed by calculating time to peak electrical activity (TTP), peak electrical activity (PEA), slope of EMG-signal and muscle activity. It was found that neuromuscular system adjustments to the task are expressed mainly by temporal (TTP) rather than amplitude (PEA) scaling of muscular activity. This change was specific for the investigated muscles. Moreover, a selective increase of muscle activity occurred while increasing external DoF. This scheme was accompanied by a significant reduction of applicable force against the device in the unstable 3 DoF condition. The findings suggest that orchestration of movement control is linked to environmental dynamics also affecting the ability to produce force under dynamic conditions. The adjustments of the neuromuscular system are rather temporal in nature being consistent with the impulse timing hypothesis of motor control.     

Force Control Deficits in Individuals with Parkinson’s Disease,Multiple Systems Atrophy,and Progressive Supranuclear Palsy

Objective

This study examined grip force and cognition in Parkinson’s disease (PD), Parkinsonian variant of multiple system atrophy (MSAp), progressive supranuclear palsy (PSP), and healthy controls. PD is characterized by a slower rate of force increase and decrease and the production of abnormally large grip forces. Early-stage PD has difficulty with the rapid contraction and relaxation of hand muscles required for precision gripping. The first goal was to determine which features of grip force are abnormal in MSAp and PSP. The second goal was to determine whether a single variable or a combination of motor and cognitive measures would distinguish patient groups. Since PSP is more cognitively impaired relative to PD and MSAp, we expected that combining motor and cognitive measures would further distinguish PSP from PD and MSAp.

Methods

We studied 44 participants: 12 PD, 12 MSAp, 8 PSP, and 12 controls. Patients were diagnosed by a movement disorders neurologist and were tested off anti-Parkinsonian medication. Participants completed a visually guided grip force task wherein force pulses were produced for 2 s, followed by 1 s of rest. We also conducted four cognitive tests.

Results

PD, MSAp, and PSP were slower at contracting and relaxing force and produced longer pulse durations compared to controls. PSP produced additional force pulses during the task and were more cognitively impaired relative to other groups. A receiver operator characteristic analysis revealed that the combination of number of pulses and Brief Test of Attention (BTA) discriminated PSP from PD, MSAp, and controls with a high degree of sensitivity and specificity.

Conclusions

Slowness in contracting and relaxing force represent general features of PD, MSAp, and PSP, whereas producing additional force pulses was specific to PSP. Combining motor and cognitive measures provides a robust method for characterizing behavioral features of PSP compared to MSAp and PD.     

Ready steady slow: action preparation slows the subjective passage of time

Professional ball game players report the feeling of the ball ‘slowing-down’ before hitting it. Because effective motor preparation is critical in achieving such expert motor performance, these anecdotal comments imply that the subjective passage of time may be influenced by preparation for action. Previous reports of temporal illusions associated with action generally emphasize compensation for suppressed sensory signals that accompany motor commands. Here, we show that the time is perceived slowed-down during preparation of a ballistic reaching movement before action, involving enhancement of sensory processing. Preparing for a reaching movement increased perceived duration of a visual stimulus. This effect was tightly linked to action preparation, because the amount of temporal dilation increased with the information about the upcoming movement. Furthermore, we showed a reduction of perceived frequency for flickering stimuli and an enhanced detection of rapidly presented letters during action preparation, suggesting increased temporal resolution of visual perception during action preparation. We propose that the temporal dilation during action preparation reflects the function of the brain to maximize the capacity of sensory information-acquisition prior to execution of a ballistic movement. This strategy might facilitate changing or inhibiting the planned action in response to last-minute changes in the external environment.     

The effect of attempted ballistic training on the force and speed of movements

Athletes in sports requiring explosive movements might benefit from a unique form of training in which a limb is restrained while the athlete attempts ballistic (explosive) movements. We investigated the effects of such ballistic training and conventional resistance training on force and speed of front kicks, side kicks, and palm strikes of martial artists. We assigned subjects randomly to an experimental group (n = 13) or a control (normal martial art training) group (n = 9). Conventional resistance training produced a gain of 12% (95% likely limits +/- 13%) in front kick force relative to the control group. Overall ballistic training and conventional resistance training decreased side kick force by 15% (+/-14%), but movement speeds increased by 11-21% (+/-13-17%). Responses to ballistic training were generally more marked in more highly skilled athletes. Attempted ballistic training may be a beneficial adjunct to resistance training for skilled athletes in sports where speed rather than force is critical.     

The acute effects of dynamic and ballistic stretching on vertical jump height, force, and power

Stretching before performance is a common practice among athletes in hopes of increasing performance and reducing the risk of injury. However, cumulative results indicate a negative impact of static stretching and proprioceptive neuromuscular facilitation (PNF) on performance; thus, there is a need for evaluating other stretching strategies for effective warm-up. The purpose of this study was to compare the differences between two sets of ballistic stretching and two sets of a dynamic stretching routine on vertical jump performance. Twenty healthy male and female college students between the ages of 22 and 34 (24.8 +/- 3 years) volunteered to participate in this study. All subjects completed three individual testing sessions on three nonconsecutive days. On each day, the subjects completed one of three treatments (no stretch, ballistic stretch, and dynamic stretch). Intraclass reliability was determined using the data obtained from each subject. A paired samples t-test revealed no significant difference in jump height, force, or power when comparing no stretch with ballistic stretch. A significant difference was found on jump power when comparing no stretch with dynamic stretch, but no significant difference was found for jump height or force. Statistics showed a very high reliability when measuring jump height, force, and power using the Kistler Quattro Jump force plate. It seems that neither dynamic stretching nor ballistic stretching will result in an increase in vertical jump height or force. However, dynamic stretching elicited gains in jump power poststretch.     

The Role of Motivation,Glucose and Self-Control in the Antisaccade Task

Research shows that self-control is resource limited and there is a gradual weakening in consecutive self-control task performance akin to muscle fatigue. A body of evidence suggests that the resource is glucose and consuming glucose reduces this effect. This study examined the effect of glucose on performance in the antisaccade task - which requires self-control through generating a voluntary eye movement away from a target - following self-control exertion in the Stroop task. The effects of motivation and individual differences in self-control were also explored. In a double-blind design, 67 young healthy adults received a 25g glucose or inert placebo drink. Glucose did not enhance antisaccade performance following self-control exertion in the Stroop task. Motivation however, predicted performance on the antisaccade task; more specifically high motivation ameliorated performance decrements observed after initial self-control exertion. In addition, individuals with high levels of self-control performed better on certain aspects of the antisaccade task after administration of a glucose drink. The results of this study suggest that the antisaccade task might be a powerful paradigm, which could be used as a more objective measure of self-control. Moreover, the results indicate that level of motivation and individual differences in self-control should be taken into account when investigating deficiencies in self-control following prior exertion.     

Breastfeeding and child disability: A comparison of siblings from the United States

Little is known about whether breastfeeding may prevent disabilities throughout childhood. We evaluate the effects of breastfeeding on child disability using data from the National Survey of Family Growth merged to the National Health Interview Survey for a large nationally representative sample of children aged 1–18 years from the U.S. including over 3000 siblings who are discordant on breastfeeding status/duration. We focus on a mother fixed effect model that compares siblings in order to account for family-level unobservable confounders and employ multiple specifications including a dynamic model that accounts for disability status of the prior child. Breastfeeding the child for a longer duration is associated with a lower risk of child disability, by about 0.2 percentage-points per month of breastfeeding. This effect is only observed on the intensive margin among breastfed children, as any breastfeeding has no effect on the extensive margin. We conclude that very short breastfeeding durations are unlikely to have an effect on reducing disability risk.     

Acute effects of static and ballistic stretching on measures of strength and power

Preactivity stretching is commonly performed by athletes as part of their warm-up routine. However, the most recent literature questions the effectiveness of preactivity stretching. One limitation of this research is that the stretching duration is not realistic for most athletes. Therefore, the purpose of this study was to determine the effects of a practical duration of acute static and ballistic stretching on vertical jump (VJ), lower-extremity power, and quadriceps and hamstring torque. Twenty-four subjects performed a 5-minute warm-up followed by each of the following three conditions on separate days with order counterbalanced: static stretching, ballistic stretching, or no-stretch control condition. Vertical jump was determined with the Vertec VJ system and was also calculated from the ground-reaction forces collected from a Kistler force plate, which also were used to calculate power. Torque output of the quadriceps and hamstrings was measured through knee extension and flexion on the Biodex System 3 Dynamometer at 60 degrees x s(-1). Data normalized for body weight were analyzed using five separate, 3 (stretch condition) x 2 (gender) analysis-of-variance procedures with repeated measures on the factor of stretch condition. The gender x stretch interaction was not significant for any of the four measures, suggesting that the stretching conditions did not affect men and women differently. The results of this study reveal that static and ballistic stretching did not affect VJ, or torque output for the quadriceps and hamstrings. Despite no adverse effect on VJ, stretching did cause a decrease in lower-extremity power, which was surprising. Because of the mixed results, strength coaches would be better served to use dynamic stretching before activity; this has been consistently supported by the literature.     

Neural Tuning Functions Underlie Both Generalization and Interference

In sports, the role of backswing is considered critical for generating a good shot, even though it plays no direct role in hitting the ball. We recently demonstrated the scientific basis of this phenomenon by showing that immediate past movement affects the learning and recall of motor memories. This effect occurred regardless of whether the past contextual movement was performed actively, passively, or shown visually. In force field studies, it has been shown that motor memories generalize locally and that the level of compensation decays as a function of movement angle away from the trained movement. Here we examine if the contextual effect of past movement exhibits similar patterns of generalization and whether it can explain behavior seen in interference studies. Using a single force-field learning task, the directional tuning curves of both the prior contextual movement and the subsequent force field adaptive movements were measured. The adaptation movement direction showed strong directional tuning, decaying to zero by 90° relative to the training direction. The contextual movement direction exhibited a similar directional tuning, although the effect was always above 60%. We then investigated the directional tuning of the passive contextual movement using interference tasks, where the contextual movements that uniquely specified the force field direction were separated by ±15° or ±45°. Both groups showed a pronounced tuning effect, which could be well explained by the directional tuning functions for single force fields. Our results show that contextual effect of past movement influences predictive force compensation, even when adaptation does not require contextual information. However, when such past movement contextual information is crucial to the task, such as in an interference study, it plays a strong role in motor memory learning and recall. This work demonstrates that similar tuning responses underlie both generalization of movement direction during dynamic learning and contextual movements in both single force field and interference tasks.     

Does the terminal-link effect depend on duration or reinforcement rate?

Preference in concurrent chains for the richer terminal-link schedule becomes more extreme as the schedule values increase with their ratio held constant, a result known as the terminal-link effect. We report two experiments that attempt to determine whether this effect is related to terminal-link duration or the overall rate of reinforcement. These variables have been confounded in prior studies, but can be separated by comparing variable-duration schedules that end after a single reinforcer has been earned, with constant-duration schedules during which a variable number of reinforcers may be earned. In Experiment 1, the terminal-link effect was obtained with variable-duration schedules when duration and overall reinforcement rate were manipulated, but not with constant-duration schedules when overall reinforcement rate was changed with duration held constant. In Experiment 2, the terminal-link effect was obtained with constant-duration schedules when duration was manipulated with overall reinforcement rate held constant. Taken together, these results show that the terminal-link effect depends on changes in terminal-link duration, not overall reinforcement rate (or equivalently, average time to reinforcement). This accords with the account of the terminal-link effect provided by the contextual choice model [J. Exp. Anal. Behav. 61 (1994) 113] but not delay-reduction theory [J. Exp. Anal. Behav. 12 (1969) 723].     

Torso flexion modulates stiffness and reflex response.

Neuromuscular factors that contribute to spinal stability include trunk stiffness from passive and active tissues as well as active feedback from reflex response in the paraspinal muscles. Trunk flexion postures are a recognized risk factor for occupational low-back pain and may influence these stabilizing control factors. Sixteen healthy adult subjects participated in an experiment to record trunk stiffness and paraspinal muscle reflex gain during voluntary isometric trunk extension exertions. The protocol was designed to achieve trunk flexion without concomitant influences of external gravitational moment, i.e., decouple the effects of trunk flexion posture from trunk moment. Systems identification analyses identified reflex gain by quantifying the relation between applied force disturbances and time-dependent EMG response in the lumbar paraspinal muscles. Trunk stiffness was characterized from a second order model describing the dynamic relation between the force disturbances versus the kinematic response of the torso. Trunk stiffness increased significantly with flexion angle and exertion level. This was attributed to passive tissue contributions to stiffness. Reflex gain declined significantly with trunk flexion angle but increased with exertion level. These trends were attributed to correlated changes in baseline EMG recruitment in the lumbar paraspinal muscles. Female subjects demonstrated greater reflex gain than males and the decline in reflex gain with flexion angle was greater in females than in males. Results reveal that torso flexion influences neuromuscular factors that control spinal stability and suggest that posture may contribute to the risk of instability injury.     

Comparative effects of food and water deprivation on movement patterns in the pigeon (Columba Livia)

Groups of naive pigeons were either food or water deprived and exposed to response-independent fixed time schedules of reinforcement. Reinforcers were always appropriate to the deprivation state. After 15 Phase One sessions under the original deprivation state, an additional 15 Phase Two sessions were run under the alternate deprivation regimen. The Phase One results indicated that the frequency of movement over time, as measured by floorboard panels, had a characteristic distribution depending on deprivation state. After state-switch in Phase Two, both groups exhibited changes in frequency distribution over time, but the new distributions were different from those produced in subjects without any deprivation history. There appeared to be sustained effects on movement patterns due to prior exposure to alternate deprivation and periodic feeding regiments, results which confirm earlier experimental work. The findings are discussed in light of research on the effect of prior response-independent schedule training, the matching law, and the effects of contextual conditioning.     

Effects of vibration training in reducing risk of slip-related falls among young adults with obesity

This study examined the effects of controlled whole-body vibration training on reducing risk of slip-related falls in people with obesity. Twenty-three young adults with obesity were randomly assigned into either the vibration or placebo group. The vibration and placebo groups respectively received 6-week vibration and placebo training on a side-alternating vibration platform. Before and after the training, the isometric knee extensors strength capacity was measured for the two groups. Both groups were also exposed to a standardized slip induced by a treadmill during gait prior to and following the training. Dynamic stability and fall incidences responding to the slip were also assessed. The results indicated that vibration training significantly increased the muscle strength and improved dynamic stability control at recovery touchdown after the slip occurrence. The improved dynamic stability could be resulted from the enhanced trunk segment movement control, which may be attributable to the strength increment caused by the vibration training. The decline of the fall rates from the pre-training slip to the post-training one was greater among the vibration group than the placebo group (45% vs. 25%). Vibration-based training could be a promising alternative or additional modality to active exercise-based fall prevention programs for people with obesity.     

The mechanism of electromyographic silent periods preceding a ballistic voluntary plantar flexion]

The present study was designed to investigate the neurophysiological mechanism of electromyographic silent periods(SP) preceding a ballistic voluntary movement. Ten male subjects were asked to respond to the flashing light by performing a plantar flexion as strongly and quickly as possible. The myoelectric signals from agonist (m. gastrocnemius, caput laterale: LG, m. soleus: SOL) and antagonist (m. tibialis anterior: TA) were simultaneously recorded together with the isometric contraction force signal. The excitability of the alpha motoneuron pools by means of the H reflex analysis was also determined at various phases of the movement. The results obtained are as follows: 1) In five out of 10 subjects, the electromyographic silent period was consistently observed (SP Group), while the rest of the subjects did not show such changes (NSP Group). 2) The maximum rate of tension raise (dF/dt) in SP Group (32.3 +/- 24.9 N/ms) was significantly (p less than .05) greater than NSP Group (15.1 +/- 12.0 N/ms). 3) In SP Group, the averaged H-wave mean amplitude decreased about 40ms prior to the appearance of SP. From these results, it can be concluded that SP in this study was attributable to the supraspinal influences so as to allow a specific motor program to be executed for selective recruitment of phasic (high threshold) motor units.     

Consolidation of dynamic motor learning is not disrupted by rTMS of primary motor cortex

Motor skills, once learned, are often retained over a long period of time. However, such learning first undergoes a period of consolidation after practice. During this time, the motor memory is susceptible to being disrupted by the performance of another motor-learning task. Recently, it was shown that repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex could disrupt the retention of a newly learned ballistic task in which subjects had to oppose their index finger and thumb as rapidly as possible. Here we investigate whether the motor cortex is similarly involved during the consolidation that follows learning novel dynamics. We applied rTMS to primary motor cortex shortly after subjects had either learned to compensate for a dynamic force field applied to their index finger or learned a ballistic finger abduction task. rTMS severely degraded the retention of the learning for the ballistic task but had no effect on retention of the dynamic force-field learning. This suggests that, unlike learning of simple ballistic skills, learning of dynamics may be stored in a more distributed manner, possibly outside the primary motor cortex.     

Effects of pollen load, parasitoids and the environment on pre-dispersal seed predation in the cleistogamous Ruellia nudiflora

Few studies have simultaneously addressed the effects of biotic and abiotic factors on pre-dispersal seed predation (PSP). Plant–seed predator interactions may be influenced by natural enemies and pollinators (the latter through changes in fruit or seed traits), and the activity of pre-dispersal seed predators and their natural enemies may both be affected by the abiotic environment. Additionally, in the case of cleistogamous plants with fruit dimorphism, PSP may be biased towards larger and more seeded chasmogamous (CH) fruits [relative to the smaller cleistogamous (CL) fruits], and the effects of biotic and abiotic factors may be contingent upon this fruit dimorphism. We studied PSP in the cleistogamous Ruellia nudiflora using a split-plot experimental design and asked the following: (1) is PSP biased towards CH fruits and is there an effect of pollen load on PSP? (2) Do parasitoids influence PSP and is their effect influenced by pollen load or fruit type? And (3) do light and water availability modify PSP and parasitoid effects? PSP was higher for CH relative to CL fruits, and under low water availability it was lower for pollen-supplemented CH fruits relative to open-pollinated CH fruits. Parasitoids were not influenced by abiotic conditions, but their negative effect on PSP was stronger for pollen-supplemented CH fruits. Overall, we show that fruit dimorphism, abiotic factors and natural enemies affect PSP, and that these effects can be non-additive.     

The electromyographical basis of inaccurate motor performance

The aim of this study was to investigate the electromyographical basis of inaccurate movement by identifying the variate and invariate characteristics of a ballistic, isometric precision-grip skill. Our results have shown that in most subjects investigated, IEMG, discharge rate and the patterns of muscle synergy were variate movement parameters while the sequence of muscle activation, the relative duration of muscle activity and the time to peak force (rise-time) remained essentially invariate. Based on these results, we can conclude that inaccurate performance of this skill, in most of the subjects investigated, was more dependent upon changes in muscle IEMG than in alterations in the temporal sequencing of muscle activity. It was apparent that from trial to trial, subjects had more difficulty in reproducing the appropriate levels of muscle contraction and synergy than in reproducing the required periods of action.     

Efficacy of prior eccentric exercise in attenuating impaired exercise performance after muscle injury in resistance trained men

Previous research has demonstrated that prior exercise may reduce the magnitude of muscle soreness and impaired function (i.e., repeated bout effect [RBE]) observed during subsequent eccentric exercise. Previous investigations have predominantly used research designs that include single-joint exercise performed by untrained individuals. It is unknown how resistance trained individuals respond to novel multi-joint eccentric actions of the upper body and whether prior exercise offers protection. Thirty-one resistance trained men (23.4 +/- 3.5 y, 177.2 +/- 5.1 cm, 86.4 +/- 16.5 kg, mean +/- SD) were randomly assigned to repeated bout ([RB] N = 15) or single bout ([CON] N = 16) conditions. Both groups performed 100 eccentric actions of the bench press ([ECC] at 70% concentric 1 repetition maximum) to induce muscle injury. Bilateral maximal isometric force, dynamic exercise performance (e.g., bench press throws), and muscle soreness were measured before, immediately after, and at 24 and 48 hours post-ECC. Total work, percent fatigue, and rating of perceived exertion (ECC) data were collected during ECC. Those assigned to RB condition exhibited less fatigue (9.5 vs. 22.6%) and lower RPE (14.8 vs. 17.1) during ECC. A significant interaction (p < 0.05) was found such that RB individuals experienced less soreness at 24 (6.5 vs. 4.9) and 48 (6.6 vs. 3.9) hours postexercise than the CON condition. No significant group differences (p < 0.05) were found for any measured performance variable. Although soreness, fatigue, and RPE suggest a RBE, this was not found in regards to exercise performance. It appears that in trained men, performing a strenuous high-volume eccentric exercise bout 2 weeks prior to an identical future bout offers no additional amelioration of impaired exercise performance.     

人PSP94与TNFα衍生物联合治疗人前列腺癌的实验研究

构建了表达人 PSP94、TNFα衍生物 ( TNFα D1 1 a)及 PSP94与 TNFα D1 1 a( PSP94- TNFαD1 1 a)双功能蛋白真核表达质粒 pc DNA- TNFα D1 1 a、pc DNA- PSP94和 pc DNA- PSP94- TNFαD1 1 a,与 rh PSP94和 rh TNFα D1 1 a蛋白分别在人前列腺癌裸鼠移植瘤动物模型上进行了 PSP94与 TNFαD1 1 a联合治疗人前列腺癌的实验研究 .当动物肿瘤直径长至约 1 0 mm时 ,将以上 3种真核表达质粒分别以 50 μg/只的量给相应组动物的左右四头肌内注射一次 ,同时设 pc DNA3.0空载体对照组 ;rh PSP9450μg/kg、rh TNFαD1 1 a 1 0 0万单位 /kg、rh PSP94和 rh TNFαD1 1 a以同样剂量联合给药 ,肌肉注射 ,每 d一次 ,连续 1 0 d,同时设环磷酰胺阳性对照组和生理盐水阴性对照组 .基因治疗动物给药后第 1 5d处死 ,蛋白治疗组停药后第 2 d处死 ,观察疗效 ,计算抑瘤率 .结果显示 ,以上述方式给药 ,无论是基因治疗组还是重组蛋白组 ,给 PSP94的动物肿瘤虽然未见明显缩小 ,但肿瘤组织均出现不同程度的坏死和液化现象 ;给 TNFαD1 1 a的未见明显的抑瘤效果 ;PSP94-TNFαD1 1 a融合基因或 rh PSP94+ rh TNFαD1 1 a联合给药 ,不仅肿瘤有所缩小 ,而且也有不同程度的坏死和液化现象出现 .初步认为 :( 1 ) PSP94有一定的抗前列腺     

云芝糖肽对氧化偶氮甲烷-葡聚糖硫酸钠诱导小鼠结直肠癌模型中相关肠道菌的影响及潜在意义

旨在探究云芝糖肽(polysaccharopeptide, PSP)对炎症相关结直肠癌(colorectal cancer, CRC)模型小鼠中肠道潜在致病菌和益生菌的影响。将雄性C57BL/6小鼠随机分为对照组、模型组和PSP组,每组10只。模型组和PSP组以氧化偶氮甲烷(azoxymethane,AOM)/葡聚糖硫酸钠(dextran sodium sulfate,DSS)造模。PSP组在造模基础上每日灌胃PSP 650 mg/kg,持续13周。小鼠炎症状态以疾病活动指数(disease activity index, DAI)进行评估。采用实时荧光定量聚合酶链反应技术测定各组小鼠新鲜粪便中厌氧消化链球菌(Peptostreptococcus anaerobius,P. anaerobius)、嗜黏蛋白阿克曼菌(Akkermansia muciniphila,A. muciniphila)、脆弱拟杆菌(Bacteroides fragilis, B．fragilis)、共生梭菌(Clostridium symbiosum, C．symbiosum)及乳酸杆菌(Lactobacillus spp.)的相对丰度。结果显示,PSP可降低造模所导致的小鼠DAI值升高,且在前两轮DSS处理时与模型组比较有显著性差异(P<0.05、 P<0.01)。PSP下调潜在致病菌P. anaerobius、A.muciniphila、B.fragilis以及C.symbiosum的相对丰度,且中期时P.anaerobius、A.muciniphila、 B．fragilis的丰度均显著低于初始水平(P<0.05、 P<0.01、 P<0.05)。表明PSP可缓解致炎剂诱导的小鼠结肠炎症,并降低部分肠道致病菌的相对丰度,提示PSP对炎症相关CRC可能具有潜在的预防作用。