Increased risk of lower limb osteoarthritis among former professional soccer (football) players.

BACKGROUND: Soccer is a high-speed contact sport with risk of injury. Despite long-standing concern, evidence to date remains inconsistent as to the association between playing professional-level soccer and lifelong musculoskeletal consequences. AIMS: The objectives were to assess risk of osteoarthritis in former professional soccer players compared to matched general population controls, and subsequently assess associated musculoskeletal disorders which may contribute to, or result from, osteoarthritis-specifically meniscal injury and joint replacement. METHODS: We conducted a retrospective cohort study using national electronic health records (EHRs) on a cohort of 7676 former professional soccer players aged 40 or over at recruitment, matched on year of birth, sex (all male) and socio-economic status with 23 028 general population controls. Outcomes of interest were obtained by utilizing individual-level record linkage to EHRs from general hospital inpatient and day-case admissions. RESULTS: Compared to controls, former soccer players showed a greater risk of hospital admission for osteoarthritis (hazard ratio [HR] 3.01; 95% confidence interval [CI] 2.80-3.25; P < 0.001). This increased risk appeared age dependant, normalizing over age 80 years and reflective of increased risk of lower limb osteoarthritis. Further, risk of hospital admissions for meniscal injury (HR 2.73; 95% CI 2.42-3.08; P < 0.001) and joint replacement (HR 2.82; 95% CI 2.23-3.57; P < 0.001) were greater among former soccer players. CONCLUSIONS: We report an increased risk of lower limb osteoarthritis in former soccer players when compared with matched population controls. The results of this research add data in support of lower limb osteoarthritis among former soccer players representing a potential industrial injury.

The power of effective study design in animal experimentation: Exploring the statistical and ethical implications of asking multiple questions of a data set.

One of the chief advantages of using highly standardised biological models including model organisms is that multiple variables can be precisely controlled so that the variable of interest is more easily studied. However, such an approach often obscures effects in sub-populations resulting from natural population heterogeneity. Efforts to expand our fundamental understanding of multiple sub-populations are in progress. However, such stratified or personalised approaches require fundamental modifications of our usual study designs that should be implemented in Brain, Behavior and Immunity (BBI) research going forward. Here we explore the statistical feasibility of asking multiple questions (including incorporating sex) within the same experimental cohort using statistical simulations of real data. We illustrate and discuss the large explosion in sample numbers necessary to detect effects with appropriate power for every additional question posed using the same data set. This exploration highlights the strong likelihood of type II errors (false negatives) for standard data and type I errors when dealing with complex genomic data, where studies are too under-powered to appropriately test these interactions. We show this power may differ for males and females in high throughput data sets such as RNA sequencing. We offer a rationale for the use of alternative experimental and statistical strategies based on interdisciplinary insights and discuss the real-world implications of increasing the complexities of our experimental designs, and the implications of not attempting to alter our experimental designs going forward.

Gender-specific effects of COVID-19 lockdowns on scientific publishing productivity: Impact and resilience.

RATIONALE: The SARS-CoV2 pandemic led to drastic social restrictions globally. Early data suggest that women in science have been more adversely affected by these lockdowns than men, with relatively fewer scientific articles authored by women. However, these observations test broad populations with many potential causes of disparity. Australia presents a natural experimental condition where several states of similar demographics and disease impact had differing approaches in their social isolation strategies. The state of Victoria experienced 280 days of lockdowns from 2020 to 2021, whereas the comparable state of New South Wales experienced 107 days, most of these in 2021, and other states even fewer restrictions. OBJECTIVE AND METHODS: To assess how the gender balance changed in Australian biomedical publishing with the lockdowns, we created a custom workflow to analyse PubMed data from more than 120,000 published articles submitted in 2019-2021 from Australian authors. RESULTS: Broadly, Australian women have been incredibly resilient to the challenges faced by the lockdowns. There was an increase in the number of published articles submitted in 2020 that was equally due to women as men, including from Victoria. On the other hand, articles specifically addressing COVID-19 were significantly less likely to be authored by women than those on other topics, a finding not likely due to particular gender imbalance in virology or viral epidemiology, since publications on HIV followed similar patterns to previous years. By 2021, this imbalance had reversed, with more COVID-19-related papers authored by women than men. CONCLUSIONS: These data suggest women from Victoria were less able to rapidly transition to new research early in the pandemic but had accommodated to the new conditions by 2021. This work indicates we need strategies to support women in science as the pandemic continues and to continue to monitor the situation for its impact on vulnerable groups.

Electron acceleration at oblique angles via stimulated Raman scattering at laser irradiance >10

The generation of hot, directional electrons via laser-driven stimulated Raman scattering (SRS) is a topic of great importance in inertial confinement fusion (ICF) schemes. Little recent research has been dedicated to this process at high laser intensity, in which back, side, and forward scatter simultaneously occur in high energy density plasmas, of relevance to, for example, shock ignition ICF. We present an experimental and particle-in-cell (PIC) investigation of hot electron production from SRS in the forward and near-forward directions from a single speckle laser of wavelength λ_{0}=1.053µm, peak laser intensities in the range I_{0}=0.2-1.0×10^{17}Wcm^{-2} and target electron densities between n_{e}=0.3-1.6%n_{c}, where n_{c} is the plasma critical density. As the intensity and density are increased, the hot electron spectrum changes from a sharp cutoff to an extended spectrum with a slope temperature T=34±1keV and maximum measured energy of 350 keV experimentally. Multidimensional PIC simulations indicate that the high energy electrons are primarily generated from SRS-driven electron plasma wave phase fronts with k vectors angled ∼50^{∘} with respect to the laser axis. These results are consistent with analytical arguments that the spatial gain is maximized at an angle which balances the tendency for the growth rate to be larger for larger scattered light wave angles until the kinetic damping of the plasma wave becomes important. The efficiency of generated high energy electrons drops significantly with a reduction in either laser intensity or target electron density, which is a result of the rapid drop in growth rate of Raman scattering at angles in the forward direction.

Neuroimmunology of the female brain across the lifespan: Plasticity to psychopathology.

The female brain is highly dynamic and can fundamentally remodel throughout the normal ovarian cycle as well as in critical life stages including perinatal development, pregnancy and old-age. As such, females are particularly vulnerable to infections, psychological disorders, certain cancers, and cognitive impairments. We will present the latest evidence on the female brain; how it develops through the neonatal period; how it changes through the ovarian cycle in normal individuals; how it adapts to pregnancy and postpartum; how it responds to illness and disease, particularly cancer; and, finally, how it is shaped by old age. Throughout, we will highlight female vulnerability to and resilience against disease and dysfunction in the face of environmental challenges.

Tranexamic acid toxicity in human periarticular tissues.

OBJECTIVES: Tranexamic acid (TXA) is an anti-fibrinolytic medication commonly used to reduce perioperative bleeding. Increasingly, topical administration as an intra-articular injection or perioperative wash is being administered during surgery. Adult soft tissues have a poor regenerative capacity and therefore damage to these tissues can be harmful to the patient. This study investigated the effects of TXA on human periarticular tissues and primary cell cultures using clinically relevant concentrations. METHODS: Tendon, synovium, and cartilage obtained from routine orthopaedic surgeries were used for ex vivo and in vitro studies using various concentrations of TXA. The in vitro effect of TXA on primary cultured tenocytes, fibroblast-like synoviocytes, and chondrocytes was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assays, fluorescent microscopy, and multi-protein apoptotic arrays for cell death. RESULTS: There was a significant (p < 0.01) increase in cell death within all tissue explants treated with 100 mg/ml TXA. MTT assays revealed a significant (p < 0.05) decrease in cell viability in all tissues following treatment with 50 mg/ml or 100 mg/ml of TXA within four hours. There was a significant (p < 0.05) increase in cell apoptosis after one hour of exposure to TXA (100 mg/ml) in all tissues. CONCLUSION: The current study demonstrates that TXA caused significant periarticular tissue toxicity ex vivo and in vitro at commonly used clinical concentrations.Cite this article: M. McLean, K. McCall, I. D. M. Smith, M. Blyth, S. M. Kitson, L. A. N. Crowe, W. J. Leach, B. P. Rooney, S. J. Spencer, M. Mullen, J. L. Campton, I. B. McInnes, M. Akbar, N. L. Millar. Tranexamic acid toxicity in human periarticular tissues. Bone Joint Res 2019;8:11-18. DOI: 10.1302/2046-3758.81.BJR-2018-0181.R1.

Quantifying SIMS of Organic Mixtures and Depth Profiles-Characterizing Matrix Effects of Fragment Ions.

Sets of matrix factors, Ξ, are reported for the first time for secondary ions in secondary ion mass spectrometry for several binary organic systems. These show the interplay of the effects of ion velocity, fragment chemistry, and the secondary ion point of origin. Matrix factors are reported for negative ions for Irganox 1010 with FMOC or Irganox 1098 and, for both positive and negative ions, with Ir(ppy)2(acac). For Irganox 1010/FMOC, the Ξ values for Irganox 1010 fall with m/z, whereas those for FMOC rise. For m/z < 250, Ξ scales very approximately with (m/z)0.5, supporting a dependence on the ion velocity at low mass. Low-mass ions generally have low matrix factors but |Ξ| may still exceed 0.5 for m/z < 50. Analysis of ion sequences with addition or loss of a hydrogen atom shows that the Ξ values for Irganox 1010 and FMOC ions change by - 0.026 and 0.24 per hydrogen atom, respectively, arising from the changing charge transfer rate constant. This effect adds to that of velocity and may be associated with the nine times more hydrogen atoms in the Irganox 1010 molecule than in FMOC. For Irganox 1098/Irganox 1010, the molecular similarity leads to small |Ξ|, except for the pseudo molecular ions where the behavior follows Irganox 1010/FMOC. For Ir(ppy)2(acac)/Irganox 1010, the positive secondary ions show twice the matrix effects of negative ions. These data provide the first overall assessment of matrix factors in organic mixtures necessary for improved understanding for quantification and the precise localization of species. Graphical Abstract ᅟ.

Neonatal overfeeding by small-litter rearing sensitises hippocampal microglial responses to immune challenge: Reversal with neonatal repeated injections of saline or minocycline.

The early-life period is extremely vulnerable to programming effects from the environment, many of which persist into adulthood. We have previously demonstrated that adult rats overfed as neonates have hypothalamic microglia that are hyper-responsive to an immune challenge, as well as hippocampal microglia that respond less efficiently to learning. We therefore hypothesised that neonatal overfeeding would alter the ability of hippocampal microglia to respond to an immune challenge with lipopolysaccharide (LPS) and that concomitant minocycline, a tetracycline antibiotic that suppresses microglial activity, could restore these responses. We induced neonatal overfeeding by manipulating the litter sizes in which Wistar rat pups were raised, so the pups were suckled in litters of four (neonatally overfed) or 12 (control-fed). We then examined the hippocampal microglial profiles 24 hour after an immune challenge with LPS and found that the neonatally overfed rats had dramatically increased microglial numbers in the hippocampus after immune challenge compared to control-fed rats. Attempts to reverse these effects with minocycline revealed repeated that neonatal injections, whether with minocycline or with saline, markedly suppressed microglial number and density throughout the hippocampus and abolished the difference between the groups in their responses to LPS. These data suggest that neonatal overfeeding not only can have lasting effects on hippocampal immune responses, but also that neonatal exposure to a protocol of repeated injections, irrespective of treatment, has a pronounced long-term impact, highlighting the importance of considering these effects when interpreting experimental data.

Ghrelin and hypothalamic NPY/AgRP expression in mice are affected by chronic early-life stress exposure in a sex-specific manner.

Early-life stress (ES) is a risk factor for metabolic disorders (e.g. obesity) with a notoriously higher prevalence in women compared to men. However, mechanisms underlying these effects remain elusive. The development of the hypothalamic feeding and metabolic regulatory circuits occurs mostly in the early sensitive postnatal phase in rodents and is tightly regulated by the metabolic hormones leptin and ghrelin. We have previously demonstrated that chronic ES reduces circulating leptin and alters adipose tissue metabolism early and later in life similarly in both sexes. However, it is unknown whether chronic ES might also affect developmental ghrelin and insulin levels, and if it induces changes in hypothalamic feeding circuits, possibly in a sex-dependent manner. We here show that chronic ES, in the form of exposure to limited nesting and bedding material from postnatal day (P)2 to P9 in mice, affects ghrelin levels differently, depending on the form of ghrelin (acylated vs desacylated), on age (P9 vs P14) and on sex, while insulin levels were similarly increased in both sexes after ES at P9. Even though ghrelin levels were more strongly affected in ES-exposed females, hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AgRP) fiber density at P14 were similarly altered in both sexes by ES. In the paraventricular nucleus of the hypothalamus, both NPY and AgRP fiber density were increased, while in the arcuate nucleus of the hypothalamus, NPY was increased and AgRP unaltered. Additionally, the hypothalamic mRNA expression of ghrelin's receptor (i.e. growth hormone secretagogue receptor) was not affected by ES. Taken together, the specific alterations found in these important regulatory circuits after ES might contribute to an altered energy balance and feeding behavior in adulthood and thereby to an increased vulnerability to develop metabolic disorders.

Depth resolution at organic interfaces sputtered by argon gas cluster ions: the effect of energy, angle and cluster size.

An analysis is presented of the effect of experimental parameters such as energy, angle and cluster size on the depth resolution in depth profiling organic materials using Ar gas cluster ions. The first results are presented of the incident ion angle dependence of the depth resolution, obtained at the Irganox 1010 to silicon interface, from profiles by X-ray photoelectron spectrometry (XPS). By analysis of all relevant published depth profile data, it is shown that such data, from delta layers in secondary ion mass spectrometry (SIMS), correlate with the XPS data from interfaces if it is assumed that the monolayers of the Irganox 1010 adjacent to the wafer substrate surface have an enhanced sputtering rate. SIMS data confirm this enhancement. These results show that the traditional relation for the depth resolution, FWHM = 2.1Y(1/3) or slightly better, FWHM = P(X)Y(1/3)/n(0.2), where n is the argon gas cluster size, and P(X) is a parameter for each material are valid both at the 45° incidence angle of the argon gas cluster sputtering ions used in most studies and at all angles from 0° to 80°. This implies that, for optimal depth profile resolution, 0° or >75° incidence may be significantly better than the 45° traditionally used, especially for the low energy per atom settings required for the best resolved profiles in organic materials. A detailed analysis, however, shows that the FWHM requires a constant contribution added in quadrature to the above such that there are minimal improvements at 0° or greater than 75°. A critical test at 75° confirms the presence of this constant contribution.

Angle dependence of argon gas cluster sputtering yields for organic materials.

The first angle-dependent measurements of the sputtering yield of an organic material using argon gas cluster ions under a wide range of conditions are reported in order to develop an analytical description of the behavior important for the development of the application of secondary ion mass spectrometry to organic and biological systems. Data are presented for Irganox 1010 using argon gas cluster ion beams of 5 and 10 keV energy, E, with cluster sizes, n, from 1000 to 5000. The measurements are conducted in an X-ray photoelectron spectrometer for a range of angles from 0 to 80° from the surface normal. The results support the Universal Equation for argon gas cluster sputtering yields with the angle dependence incorporated into the equation via a simple angle dependence of the parameter A. This explains how and why the angular dependence of the sputtering yield changes significantly with increasing E/n. These results are also accurately confirmed using the published measurements for polystyrene by Rading et al.

Effects of temperature and ammonia flow rate on the chemical vapour deposition growth of nitrogen-doped graphene.

We doped graphene in situ during synthesis from methane and ammonia on copper in a low-pressure chemical vapour deposition system, and investigated the effect of the synthesis temperature and ammonia concentration on the growth. Raman and X-ray photoelectron spectroscopy was used to investigate the quality and nitrogen content of the graphene and demonstrated that decreasing the synthesis temperature and increasing the ammonia flow rate results in an increase in the concentration of nitrogen dopants up to ca. 2.1% overall. However, concurrent scanning electron microscopy studies demonstrate that decreasing both the growth temperature from 1000 to 900 °C and increasing the N/C precursor ratio from 1/50 to 1/10 significantly decreased the growth rate by a factor of six overall. Using scanning tunnelling microscopy we show that the nitrogen was incorporated mainly in substitutional configuration, while current imaging tunnelling spectroscopy showed that the effect of the nitrogen on the density of states was visible only over a few atom distances.

The long-term outcome of uncemented Low Contact Stress total knee replacement in patients with rheumatoid arthritis: results at a mean of 22 years.

We reviewed the long-term clinical and radiological results of 63 uncemented Low Contact Stress (LCS) total knee replacements (TKRs) in 47 patients with rheumatoid arthritis. The mean age of the patients at the time of surgery was 69 years (53 to 81). At a mean follow-up of 22 years (20 to 25), 12 patients were alive (17 TKRs), 27 had died (36 TKRs), and eight (ten TKRs) were lost to follow-up. Revision was necessary in seven patients (seven TKRs, 11.1%) at a mean of 12.1 years (0 to 19) after surgery. In the surviving ten patients who had not undergone revision (15 TKRs), the mean Oxford knee score was 30.2 (16 to 41) at a mean follow-up of 19.5 years (15 to 24.7) and mean active flexion was 105° (90° to 150°). The survival rate was 88.9% at 20 years (56 of 63) and the Kaplan-Meier survival estimate, without revision, was 80.2% (95% confidence interval 37 to 100) at 25 years.

Being suckled in a large litter mitigates the effects of early-life stress on hypothalamic-pituitary-adrenal axis function in the male rat.

The perinatal environment influences stress responses in the long-term, as does body composition. Male rats suckled in large litters, where they have reduced access to milk and attention from the dam, are less anxious and have attenuated hypothalamic-pituitary-adrenal (HPA) axis responses to stress compared to rats from control litters. In the present study, we investigated whether this early-life environment can also ameliorate anxiety and HPA axis function in rats prone to be stress-sensitive. We conducted these experiments in male rats from control litters (n = 12) or large litters (n = 20). Half were given 24 h of maternal separation on postnatal day 10 to induce HPA axis hyperactivity; the remainder staying undisturbed with their dam. When the rats reached adulthood, we examined behavioural indices of anxiety (elevated plus maze) and depression (Porsolt's forced swim test) under basal conditions and after 15 min of restraint stress. We also examined neuronal activation in the paraventricular nucleus of the hypothalamus (PVN) as an index of HPA axis function. Being suckled in a large litter led to a significantly attenuated PVN response to stress in adulthood. Maternal separation strongly exacerbated the stress-induced increase in PVN neuronal activation in control rats but did not affect the PVN response in large-litter rats. Immobility in the forced swim after restraint was also exacerbated in neonatally maternally separated control rats but not in those from large litters. Our findings show that being suckled in large litters mitigates the effects of early-life stress on HPA axis function and indices of depression in the rat.

Meniscal scaffolds: early experience and review of the literature.

INTRODUCTION: Meniscal scaffold implants support the in-growth of new "meniscus like" tissue with the aim of alleviating post-meniscectomy knee pain and preventing further articular cartilage degeneration. PATIENTS AND METHODS: Twenty-three patients underwent meniscal scaffold implantation (14 medial, 9 lateral) with either the Menaflex (ReGen Biologics) (n=12) or Actifit (Orteq) (n=11) scaffolds. Minimum follow-up was 1 year with a mean of 24.1 months (18-27) for the Menaflex and 14.7 months (12-18) for the Actifit groups. Mean age at surgery was 35 years (17-47) with a mean Outerbridge grade of 1.9 in the affected compartment. Eight (36%) underwent concurrent osteotomy, ligament reconstruction or microfracture of the tibial plateau. KOOS, Lysholm, Tegner activity and IKDC scores were collected pre-operatively and at six-month interval post-surgery. Assessment of the reconstruction was obtained with MRI scanning and arthroscopy. One scaffold tore and was revised at 19 months post-operatively. RESULTS: Twenty-one out of 23 (91.3%) had a significant improvement in knee scores when compared to pre-surgery levels at latest follow-up. Second-look arthroscopy in 14 at 1-year post-implantation showed variable amounts of regenerative tissue. There was no progression in chondral wear noted on repeat MRI scanning. CONCLUSION: Treatment with meniscal scaffold implants can provide good pain relief for the post-meniscectomy knee following partial meniscectomy. Longer follow-up is required to ascertain whether they also prevent the progressive chondral wear associated with a post-meniscectomy knee.

Neural and humoral changes associated with the adjustable gastric band: insights from a rodent model.

BACKGROUND: Bariatric surgical procedures, including the laparoscopic adjustable gastric band (LAGB), are currently the only effective treatments for morbid obesity, however, there is no clear understanding of the mechanisms underpinning the efficacy of LAGB. The aim of this study is to examine changes in activation of the sensory neuronal pathways and levels of circulating gut hormones associated with inflation of an AGB. DESIGN AND RESULTS: The trajectory within the central nervous system of polysynaptic projections of sensory neurons innervating the stomach was determined using the transsynaptically transported herpes simplex virus (HSV). Populations of HSV-infected neurons were present in the brainstem, hypothalamus and cortical regions associated with energy balance. An elevation of Fos protein was present within the nucleus of the solitary tract, a region of the brainstem involved in the control of food intake, following acute and chronic band inflation. Two approaches were used to test (1) the impact of inflation of the band alone (on a standard caloric background) or (2) the impact of a standard caloric meal (on the background of the inflated band) on circulating gut hormones. Importantly, there was a significant elevation of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) following oral gavage of a liquid meal in animals with pre-inflated bands. There was no impact of inflation of the band alone on circulating GLP-1, PYY or ghrelin in animals on a standard caloric background. CONCLUSION: These data are consistent with the notion that the LAGB exerts its effects on satiety, reduced food intake and reduced body weight by the modulation of both neural and hormonal responses with the latter involving an elevation of meal-related levels of GLP-1 and PYY. These data are contrary to the view that the surgery is purely 'restrictive'.

Postnatal overfeeding leads to obesity and exacerbated febrile responses to lipopolysaccharide throughout life.

The perinatal environment can be crucial for programming long-term physiology, including the mechanisms regulating body weight, and postnatal overfeeding can lead to obesity throughout life. Inflammation-related complications are of particular concern in the obese. However, little is known about how postnatal overfeeding contributes to changes in the ability to respond to inflammation. In the present study, we investigate changes in the febrile and neurochemical response to immune challenge with lipopolysaccharide (LPS), in juvenile and adult, male and female Wistar rats made obese by overfeeding during the postnatal period. We demonstrate that febrile responses to LPS are exacerbated in these rats, with peak core temperatures being up to 0.5 °C higher compared to those in controls, and this is associated with an enhanced pro-inflammatory cytokine profile and enhanced hypothalamic-pituitary-adrenal (HPA) axis activation. Plasma pro-inflammatory cytokines concentrations were approximately three-fold greater in neonatally overfed rats after LPS and there were approximately twice as many neurones activated in the paraventricular nucleus of the hypothalamus as in controls, with a prolonged corticosterone response. We also observed elevated expression of toll-like receptors (TLR) 2 and 4 in adipose tissue and greater inhibitory factor κB phosphorylation in these obese animals. Despite similar changes in expression of adipose TLR3, there was no corresponding alteration in the response to a viral mimetic that acts at this receptor. We suggest that an elevated febrile response to LPS therefore occurs in cases of obesity and this is associated with altered HPA axis function and enhanced TLR2/4 expression in adipose tissue and an up-regulated downstream pro-inflammatory cascade.

MRSA colonisation and subsequent risk of infection despite effective eradication in orthopaedic elective surgery.

The objective of this study was to determine the effectiveness of screening and successful treatment of methicillin-resistant Staphylococcus aureus (MRSA) colonisation in elective orthopaedic patients on the subsequent risk of developing a surgical site infection (SSI) with MRSA. We screened 5933 elective orthopaedic in-patients for MRSA at pre-operative assessment. Of these, 108 (1.8%) were colonised with MRSA and 90 subsequently underwent surgery. Despite effective eradication therapy, six of these (6.7%) had an SSI within one year of surgery. Among these infections, deep sepsis occurred in four cases (4.4%) and superficial infection in two (2.2%). The responsible organism in four of the six cases was MRSA. Further analysis showed that patients undergoing surgery for joint replacement of the lower limb were at significantly increased risk of an SSI if previously colonised with MRSA. We conclude that previously MRSA-colonised patients undergoing elective surgery are at an increased risk of an SSI compared with other elective patients, and that this risk is significant for those undergoing joint replacement of the lower limb. Furthermore, when an infection occurs, it is likely to be due to MRSA.

Efficacy of post-insult minocycline administration to alter long-term hypoxia-ischemia-induced damage to the serotonergic system in the immature rat brain.

Neuroinflammation is a key mechanism contributing to long-term neuropathology observed after neonatal hypoxia-ischemia (HI). Minocycline, a second-generation tetracycline, is a potent inhibitor of neuroinflammatory mediators and is successful for at least short-term amelioration of neuronal injury after neonatal HI. However the long-term efficacy of minocycline to prevent injury to a specific neuronal network, such as the serotonergic (5-hydroxytryptamine, 5-HT) system, is not known. In a post-natal day 3 (P3) rat model of preterm HI we found significant reductions in 5-HT levels, 5-HT transporter expression and numbers of 5-HT-positive dorsal raphé neurons 6 weeks after insult compared to control animals. Numbers of activated microglia were significantly elevated in the thalamus and dorsal raphé although the greatest numbers were observed in the thalamus. Brain levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) were also significantly elevated on P45 in the thalamus and frontal cortex. Post-insult administration of minocycline for 1 week (P3-P9) attenuated the P3 HI-induced increases in numbers of activated microglia and levels of TNF-α and IL-1ß on P45 with concurrent changes in serotonergic outcomes. The parallel prevention of P3 HI-induced serotonergic changes suggests that inhibition of neuroinflammation within the first week after P3 HI injury was sufficient to prevent long-term neuroinflammation as well as serotonergic system damage still evident at 6 weeks. Thus early, post-insult administration of minocycline may target secondary neuroinflammation and represent a long-term therapy to preserve the integrity of the central serotonergic network in the preterm neonate.