Iguratimod ameliorates antibody-mediated rejection after renal transplant by modulating the Th17/Treg paradigm.

BACKGROUND: Iguratimod (IGU) is widely used in clinical practice due to its stable anti-inflammatory effects. Our previous studies have confirmed that the proportion of Th17/Treg balance in patients taking IGU altered significantly. This study aims to explore the role of IGU in antibody-mediated rejection (ABMR) and its potential mechanisms. METHODS: We conducted bioinformatics analysis of sequencing data from the GEO database to analyze the abundance of immune cell infiltration in transplanted kidney tissues. In vivo, IGU was intervened in a mice secondary skin transplantation model and a mice kidney transplantation ABMR model, and histological morphology of the grafts were examined by pathological staining, while relevant indicators were determined through qRT-PCR, immunohistochemistry, and enzyme-linked immunosorbent assay, observed T cell differentiation by flow cytometry, and preliminarily assessed the immunosuppressive effect of IGU. In vitro, we established Th17 and Treg cell induction and stimulation differentiation culture systems and added IGU for intervention to explore its effects on their differentiation. RESULTS: Through bioinformatics analysis, we found that Th17 and Treg may play important roles in the occurrence and development of ABMR. In vivo, we found that IGU could effectively reduce the damage caused by ABMR to the grafts, alleviate the infiltration of inflammatory cells in the graft tissues, and reduce the deposition of C4d in the grafts. Moreover, it is also found that IGU regulated the differentiation of Th17 and Treg cells in the spleen and peripheral blood and reduced the expression of IL-17A in the grafts and serum. In addition, same changes were observed in the induction and differentiation culture system of Th17 and Treg cells in vitro after the addition of IGU. CONCLUSION: IGU can inhibit the progression of ABMR by regulating the differentiation of Th17 and Treg cells, providing novel insights for optimizing clinical immunosuppressive treatment regimens.

Association of UGT1A Gene Polymorphisms with BKV Infection in Renal Transplantation Recipients.

BACKGROUND: BK virus (BKV) infection is an opportunistic infectious complication and constitutes a risk factor for premature graft failure in kidney transplantation. Our research aimed to identify associations and assess the impact of single-nucleotide polymorphisms (SNPs) on metabolism-related genes in patients who have undergone kidney transplantation with BKV infection.

Material/Methods: The DNA samples of 200 eligible kidney transplant recipients from our center, meeting the inclusion criteria, have been collected and extracted. Next-generation sequencing was used to genotype SNPs on metabolism-associated genes (CYP3A4/5/7, UGT1A4/7/8/9, UGT2B7). A general linear model (GLM) was used to identify and eliminate confounding factors that may influence the outcome events. Multiple inheritance models and haplotype analyses were utilized to identify variation loci associated with infection caused by BKV and ascertain haplotypes, respectively.

Results: A total of 141 SNPs located on metabolism-related genes were identified. After Hardy-Weinberg equilibrium (HWE) and minor allele frequency (MAF) analysis, 21 tagger SNPs were selected for further association analysis. Based on GLM results, no confounding factor was significant in predicting the incidence of BK polyomavirus-associated infection. Then, multiple inheritance model analyses revealed that the risk of BKV infection was significantly associated with rs3732218 and rs4556969. Finally, we detect significant associations between haplotype T-A-C of block 2 (rs4556969, rs3732218, rs12468274) and infection caused by BKV (P = 0.0004).

Conclusions: We found that genetic variants in the UGT1A gene confer BKV infection susceptibility after kidney transplantation.

IL-34 attenuates acute T cell-mediated rejection following renal transplantation by upregulating M2 macrophages polarization.

Objective: To investigate the role of Interleukin-34 (IL-34) in acute T cell-mediated rejection (TCMR) following renal transplantation. Methods: The mice acute TCMR model of renal transplantation was established and identified by hematoxylin and eosin (HE) and immunohistochemistry (IHC) staining. Then, IHC staining of IL-34 was also performed to determine the expression of IL-34 in allografts. Recipients were infected with IL-34 overexpression adeno-associated virus, infection efficiency of which was estimated by enzyme linked immunosorbent assay (ELISA), Western blot, and immunofluorescence. HE and IHC staining were used to estimate the grades of TCMR. Flow cytometry was performed on lymphocytes in spleens of recipients including regulatory T cells (Tregs) and M2 macrophages. The expression of cytokines in vivo was analyzed by Mouse Cytokine Grp I Panel. Finally, Tregs and M2 macrophages were cultured in vitro and treated with IL-34 to observe the effects of IL-34 on the differentiation of the cells. Results: The mouse TCMR model was successfully established by HE, periodic acid shiff (PAS), CD4 and CD8 IHC staining. The expression of IL-34 was significantly decreased in allografts with TCMR. BALB/c mice were successfully infected with IL-34 overexpression adeno-associated virus. Subsequently, the grade of rejection in mice TCMR model was evaluated by HE and IHC staining according to Banff criteria. It is suggested that the grade of TCMR in IL-34 overexpressed mice was significantly decreased. IHC staining and Flow cytometry showed that the proportion of Tregs and M2 macrophages in the spleens and allografts were significantly increased in IL-34 overexpressed mice. Serum levels of interferon-gamma (IFN-γ), IL-17 and tumor necrosis factor-alpha (TNF-α) were downregulated in IL-34 overexpressed mice. Moreover, IL-34 could promote macrophage M2 polarization, while failed to promote differentiation of naïve T cells into Tregs in vitro. Conclusion: Overexpression of IL-34 may attenuate the progression of TCMR episodes in allografts by increasing the polarization of M2 macrophages in the spleens and allografts, which may become a potential therapeutic strategy for TCMR.

Single-nucleotide polymorphisms of matrix metalloproteinase genes are associated with graft fibrosis after kidney transplantation.

Background: Further research needs to be conducted on the role of genetic variables in kidney transplantation fibrosis. In this study, we used next-generation sequencing (NGS) to examine the relationship between matrix metalloproteinase (MMP) genes and single-nucleotide polymorphisms (SNPs) in renal allograft fibrosis. Methods: This study comprised 200 patients, whose complete DNA samples were taken. The SNPs in MMP genes were identified using targeted NGS. Hardy-Weinberg equilibrium (HWE) and minor allele frequency (MAF) tests were conducted, followed by a linkage disequilibrium (LD) analysis. Finally, the SNPs and severity of kidney allograft fibrosis were evaluated using different inheritance models. Results: In total, 41 MMP gene-related SNPs were identified using targeted sequencing, and 20 tagger SNPs were retained for further study. The general linear models (GLMs) revealed that sirolimus treatment had a substantial effect on kidney graft fibrosis. The multiple inheritance model analyses revealed that SNP rs9059 of the MMP9 gene was strongly associated with kidney graft fibrosis. The in-vitro experiments showed the MMP9 rs9509 mutation promotes the process of epithelial-mesenchymal transition (EMT) in the human kidney 2 (HK2) cells. Conclusions: The SNP rs9059 is associated with significant kidney allograft pathological changes by promoting EMT progression. Our findings provide insights into the etiology of renal allograft interstitial fibrosis and the MMP9 could be used as a potential treatment target in the future.

Influence of SLCO1B1 Polymorphisms on the Pharmacokinetics of Mycophenolic Acid in Renal Transplant Recipients.

OBJECTIVE: This study was designed to analyze the correlation between single nucleotide polymorphisms (SNP) related to drug metabolism and pharmacokinetics of mycophenolic acid (MPA) during long-term follow-up. MATERIALS AND METHOD: A retrospective cohort study involving 71 renal transplant recipients was designed. Blood samples were collected to extract total DNAs, followed by target sequencing based on next-generation sequencing technology. The MPA area under the curve (AUC) was calculated according to the formula established in our center. The general linear model and linear regression model were used to analyze the association between SNPs and MPA AUC. RESULTS: A total of 689 SNPs were detected in our study, and 90 tagger SNPs were selected after quality control and linkage disequilibrium analysis. The general linear model analysis showed that 9 SNPs significantly influenced MPA AUC. A forward linear regression was conducted, and the model with the highest identical degree (r2=0.55) included 4 SNPs (SLCO1B1: rs4149036 [P < 0.0001], ABCC2: rs3824610 [P = 0.005], POR: rs4732514 [P = 0.006], ABCC2: rs4148395 [P = 0.007]) and 6 clinical factors (age [P < 0.0001], gender [P < 0.0001], the incident of acute rejection (AR) [P = 0.001], albumin [P < 0.0001], duration after renal transplantation [P = 0.01], lymphocyte numbers [P = 0.026]). The most relevant SNP to MPA AUC in this model was rs4149036. The subgroup analysis showed that rs4149036 had a significant influence on MPA AUC in the older group (P = 0.02), high-albumin group (P = 0.01), male group (P = 0.046), and both within-36-month group (P = 0.029) and after-36-month group (P = 0.041). The systematic review included 4 studies, and 2 of them showed that the mutation in SLCO1B1 resulted in lower MPA AUC, which was contrary to our study. CONCLUSION: A total of 4 SNPs (rs4149036, rs3824610, rs4148395, and rs4732514) were identified to be significantly correlated with MPA AUC. Rs4149036, located in SLCO1B1, was suggested to be the most relevant SNP to MPA AUC, which had a stronger influence on recipients who were elder, male, or with high serum albumin. Furthermore, 6 clinical factors, including age, gender, occurrence of acute rejection, serum albumin, time from kidney transplantation, and blood lymphocyte numbers, were found to affect the concentration of MPA.

Efficacy and Safety of Iguratimod Supplement to the Standard Immunosuppressive Regimen in Highly Mismatched Renal Transplant Recipients: A Pilot Study.

Iguratimod (IGU) can mitigate the symptoms of rheumatoid arthritis through its anti-inflammatory effects. The objective of this study was to investigate the clinical efficacy and safety of IGU in highly HLA-mismatched renal transplant recipients, in combination with standard immunosuppressive regimen. This pilot study was designed as an open-label, blank-control, randomized clinical trial on patients recruited from a single transplant center in China. Patients who met the inclusion criteria were randomized to the IGU (n=27) and blank control (n=27) groups. IGU was administrated with the conventional triple immunosuppressive protocol for 52 weeks after kidney transplantation. The incidence of biopsy-proven acute rejection rate was 14.8% (4/27) in the IGU group and 29.6% (8/27) in the control group, P = 0.19. The clinical rejection rate was also substantially reduced in the IGU group (3.7% vs. 18.5%, P = 0.08). De novo donor-specific antibody also showed a decline trend in the IGU group after 52 weeks. The graft function and incidence of adverse events were similar between the two groups. In addition, IGU intervention significantly decreased the number of NK cells throughout the follow-up. In conclusion, our study has shown the possibility that IGU could reduce the allograft rejection rate and de novo DSA with appreciable safety in combination with conventional immunosuppressants. Formal clinical trials were warranted based on current findings.

Impaired ATG16L-Dependent Autophagy Promotes Renal Interstitial Fibrosis in Chronic Renal Graft Dysfunction Through Inducing EndMT by NF-κB Signal Pathway.

Chronic renal graft dysfunction (CAD) is caused by multiple factors, including glomerular sclerosis, inflammation, interstitial fibrosis and tubular atrophy (IF/TA). However, the most prominent elements of CAD are IF/TA. Our studies have confirmed that endothelial-mesenchymal transition (EndMT) is an important source to allograft IF/TA. The characteristic of EndMT is the loss of endothelial marker and the acquisition of mesenchymal or fibroblastic phenotypes. Autophagy is an intracellular degradation pathway that is regulated by autophagy-related proteins and plays a vital role in many fibrotic conditions. However, whether or not autophagy contributes to fibrosis of renal allograft and how such mechanism occurs still remains unclear. Autophagy related 16 like gene (ATG16L) is a critical autophagy-related gene (ARG) necessary for autophagosome formation. Here, we first analyzed kidney transplant patient tissues from Gene Expression Omnibus (GEO) datasets and 60 transplant patients from our center. Recipients with stable kidney function were defined as non-CAD group and all patients in CAD group were histopathologically diagnosed with CAD. Results showed that ATG16L, as one significant differential ARG, was less expressed in CAD group compared to the non-CAD group. Furthermore, we found there were less autophagosomes and autolysosomes in transplanted kidneys of CAD patients, and downregulation of autophagy is a poor prognostic factor. In vitro, we found out that the knockdown of ATG16L enhanced the process of EndMT in human renal glomerular endothelial cells (HRGECs). In vivo, the changes of EndMT and autophagic flux were then detected in rat renal transplant models of CAD. We demonstrated the occurrence of EndMT, and indicated that abundance of ATG16L was accompanied by the dynamic autophagic flux change along different stages of kidney transplantation. Mechanistically, knockdown of ATG16L, specifically in endothelial cells, reduced of NF-κB degradation and excreted inflammatory cytokines (IL-1ß, IL-6 and TNF-α), which could facilitate EndMT. In conclusion, ATG16L-dependent autophagic flux causing by transplant showed progressive loss increase over time. Inflammatory cytokines from this process promoted EndMT, thereby leading to progression of CAD. ATG16L served as a negative regulator of EndMT and development of renal graft fibrosis, and autophagy can be explored as a potential therapeutic target for chronic renal graft dysfunction.

Single Nucleotide Polymorphisms of Ubiquitin-Related Genes were Associated with Allograft Fibrosis of Renal Transplant Fibrosis.

BACKGROUND Interstitial fibrosis and tubular atrophy (IF/TA) have been recognized as crucial factors contributing to graft loss resulting from chronic renal allograft injuries. Recent studies have indicated a significant association between the progression of organ fibrosis and single nucleotide polymorphisms (SNPs) found on certain genes. Our research sought to understand these potential associations and detect the potential impact of SNPs on ubiquitin-related genes related to allograft fibrosis in kidney transplant recipients. MATERIAL AND METHODS There were 200 patients enrolled in this study, from which samples were extracted for total DNA. Targeted next-generation sequencing was used to detect SNPs on 9 genes (FBXL21, PIAS1/2, SUMO1/2/3/4, UBE2D1, and UBE2I). Minor allele frequency (MAF) and Hardy-Weinberg equilibrium (HWE) tests were used and followed by linkage disequilibrium analysis. General linear models (GLM) were used to identify significant confounding factors. Finally, multiple inheritance models and haplotype analyses were conducted to explore associations between SNPs and the degree of the severity of renal allograft fibrosis. RESULTS In total, 144 SNPs were identified in targeted sequencing. After filtering based on results from MAF and HWE tests, 15 tagger SNPs were selected for further analyses of associations. GLMs indicated that the administration of sirolimus significantly contributed to the degree of severity of allograft fibrosis (P=0.011). After adjusting for confounding factors and applying a Bonferroni correction, multiple inheritance model analyses indicated that the recessive model of rs644731 of the PIAS2 gene was significantly correlated with the occurrence of IF/TA (P=0.01). Furthermore, single-locus based analysis of rs644731 did not indicate that it had a positive influence on IF/TA in a degree-dependent manner. Finally, linkage disequilibrium analysis revealed 3 haplotypes all lacking significant correlation with respect to the IF/TA experimental cohort. CONCLUSIONS We are the first to reveal that mutations of rs644731 in the PIAS2 gene were significantly correlated with the progression of IF/TA in kidney transplant recipients.

Population genetic polymorphism and mutation analysis of 19 autosomal STR loci in Jiangsu Han individuals in Eastern China.

Aim: Genetic polymorphisms and the mutation ratio of 19 autosomal short tandem repeat (STR) loci were analysed in 10,000 individuals and 7755 families from Jiangsu Province in Eastern China.Subjects and methods: Nineteen STR loci were amplified by a multiplex amplification system and genotyped on the ABI 3130 Genetic Analyser. Allele frequencies, forensic parameters and mutations for the 19 autosomal STR loci were statistically analysed.Results: In total, 344 genotypes were discovered. No significant deviation from Hardy-Weinberg equilibrium was observed. The combined power of discrimination reached 0.9999999999999999984341, and the combined probability of paternity exclusion was 0.999999989. The pairwise genetic distance and p-values between the Jiangsu and 17 published populations depended on the FST value calculation and are shown by the neighbour-joining evolutionary tree. No statistically significant differences were found, except for the Xinjiang Altay Han (p = 0.01802) population. The average mutation rate of the Jiangsu population across all 19 loci was 1.4 × 10-3. The average mutation rate of the 13 core CODIS STR loci remained below 2 × 10-3 and there was no difference and relatively high consistency (p < 0.001) by correlation coefficient analysis among the six groups.Conclusions: Allelic genetic polymorphisms and mutation data were obtained from a large number of samples, which indicated that the amplification kit is suitable for forensic application and that the Jiangsu population has its own genetic characteristics that are different from those of other ethnic populations.

Role of B and T Lymphocyte Attenuator in Renal Transplant Recipients with Biopsy-Proven Acute Rejection.

BACKGROUND Acute rejection is a common predisposing cause of allograft dysfunction in kidney transplantation. Recently, the B and T lymphocyte attenuator (BTLA)/herpes virus entry mediator (HVEM)/lymphotoxin (LIGHT)/CD160 pathway was found to be potentially involved in the regulation of T cell activation. This could mean that this pathway is involved in graft rejection in kidney transplantation; the present study aimed to explore this possibility. MATERIAL AND METHODS The expression of BTLA, HVEM, LIGHT and CD160 on peripheral CD4+, CD8+ and CD19+ lymphocytes were analyzed by flow cytometry in recipients with biopsy-proven acute rejection (BPAR) or stable allograft function, as well as in healthy volunteers. Moreover, we performed HE staining and immunohistochemical staining to assess the expression of BTLA and HVEM in kidney samples from recipients with BPAR and patients who underwent the surgery of radical nephrectomy. RESULTS We observed the significantly lower expression of BTLA on CD4+ T cells in recipients from the BPAR group than in recipients from the stable group. The expression of BTLA on CD8+ T cells among recipients both from the BPAR and stable group was statistically increased than that in the healthy volunteers. A significant difference in the expression of CD160 in the stable group was found when compared with the BPAR group or control group. Moreover, there was no significance in the expression of HVEM, LIGHT or CD160 on other subtypes of T cells between the 3 groups or in the expression of BTLA on CD4+ T cells between the BPAR and control group. CONCLUSIONS The findings indicate that the BTLA/HVEM pathway does be involved in pathogenesis of acute rejection following kidney transplantation, as well as the induction of transplant tolerance. This pathway may therefore be a useful target for therapy against acute rejection after kidney transplantation.

Evaluation of the NMP22 BladderChek test for detecting bladder cancer: a systematic review and meta-analysis.

BACKGROUND: We examined the usefulness of the nuclear matrix protein 22 (NMP22) BladderChek test for detecting bladder cancer. MATERIALS AND METHODS: A literature search was performed using PubMed, Embase, the Cochrane Library, and Web of Science. The diagnostic accuracy of the NMP22 BladderChek test was evaluated via pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under curve (AUC). Inter-study heterogeneity was explored using meta-regression and subgroup analyses. RESULTS: We included 23 studies in the systematic review and 19 in the quantitative meta-analysis. Overall sensitivity and specificity were 56% (52-59%) and 88% (87-89%), respectively; pooled PLR and NLR were 4.36 (3.02-6.29) and 0.51 (0.40-0.66), respectively; DOR was 9.29 (5.55-15.55) with an AUC of 0.8295. The mean sensitivity for Ta, T1, ≥ T2, Tis, G1, G2, and G3 disease was 13.68%, 29.49%, 74.03%, 34.62%, 44.16%, 56.25%, and 67.34%, respectively. CONCLUSIONS: The NMP22 BladderChek test shows good discrimination ability for detecting bladder cancer and a high-specificity algorithm that can be used for early detection to rule out patients with higher bladder cancer risk. It also has better potential for screening higher-grade and higher-stage tumors, and better diagnostic performance in Asians.

Proton Nuclear Magnetic Resonance (¹H-NMR)-Based Metabolomic Evaluation of Human Renal Allografts from Donations After Circulatory Death.

BACKGROUND Delayed graft function (DGF) is a common complication that impairs allograft function after kidney transplantation. However, the mechanism of DGF remains unclear. Nuclear magnetic resonance (NMR)-based analysis has been widely used in recent times to assess changes in metabolite levels. MATERIAL AND METHODS Samples of perfusate from allografts donated after circulatory death were collected prior to transplantation, during static cold storage. ¹H-NMR-based metabolomics combined with the statistical methods, orthogonal partial least-squares discriminant analysis (OPLS-DA), and principle-component analysis (PCA), were employed to test different levels of metabolites between the allografts that exhibited DGF and those that exhibited immediate graft function (IGF). RESULTS The study population consisted of 36 subjects, 11 with DGF and 25 with IGF. Of the 37 detected and identified metabolites, a-glucose and citrate were significantly elevated in the perfusate of DGF allografts, and taurine and betaine were significantly decreased. CONCLUSIONS ¹H-NMR analysis of DGF and IGF perfusates revealed some significant differences in their metabolite profiles, which may help explain the mechanisms of kidney ischemia-reperfusion injury and DGF.

Transforming Growth Factor-ß1 Induces Endothelial-to-Mesenchymal Transition via Akt Signaling Pathway in Renal Transplant Recipients with Chronic Allograft Dysfunction.

BACKGROUND Chronic allograft dysfunction (CAD) is the major cause of chronic loss of allograft in kidney transplant recipients. Kidney interstitial fibrosis is identified to be strongly associated with CAD in kidney transplantation. Recently, endothelial-to-mesenchymal transition (EndMT) has been identified as one of the potential mechanisms in kidney interstitial fibrosis. MATERIAL AND METHODS Kidney tissue samples from 25 renal transplant recipients (RTRs) with CAD and healthy volunteers were collected for HE (hematoxylin-eosin), Masson trichrome, and immunohistochemical staining, and indirect immunofluorescence double-staining assay. Moreover, human umbilical vascular endothelial cells (HUVECs) were cultured and treated with TGF-ß1 at different doses or intervals. The protein expressions of α-SMA and CD31 were determined by Western blot assay. Furthermore, potential signaling pathways involved in EndMT induced by TGF-ß1were also investigated by Western blotting. RESULTS Typical interstitial fibrosis was observed in transplanted renal tissues from the CAD group. We also found a significant increase of TGF-ß1 expression in renal tissues from RTRs with CAD compared with the normal group. Moreover, significant over-expressions of α-SMA, collagen-I, and collagen-III and under-expression of CD31 were detected in kidney specimens of the CAD group. Similar expressive tendencies of α-SMA and CD31 proteins were found in HUVECs treated with TGF-ß1 in both time-dependent and dose-dependent manners. The activation of the Akt signaling pathway was found in HUVECs induced by TGF-ß1 and selective inhibitors. CONCLUSIONS EndMT was observed in kidney tissues from RTRs with CAD, and TGF-ß1 can induce the process of EndMT in both time-dependent and does-dependent manners through the Akt signaling pathway.

[Analysis of the main components of inner ear antigens inducing autoimmune Meniere's disease in guinea pigs].

OBJECTIVE: To investigate the main components of inner ear antigens inducing autoimmune Meniere's disease (AIMD) in guinea pigs. METHODS: The guinea pigs were immunized with isologous crude inner ear antigens (ICIEAg). Then, the hearing function was measured with auditory brainstem response (ABR), the vestibular function was measured with electronystagmography (including spontaneous nystagmus and caloric test), and inner ear histopathological changes were observed by inner ear celloidin section with haematoxylin-eosin staining and observed under light microscope. According to these results, the AIMD-model animals from non-AIMD-model ones were distinguished. The special antibodies against ICIEAg in sera were measured with ELISA. The antigen-antibody reactions against different components of ICIEAg were detected by Western blotting with sera of AIMD and non-AIMD guinea pigs respectively. Then, we analysed the contrast between them and found the main components of the ICIEAg that were positive reaction in AIMD guinea pigs and negative reaction in non-AIMD guinea pigs. RESULTS: The result of ELISA demonstrated that the sera of both the AIMD and non-AIMD guniea pigs contained the special antibodies against ICIEAg after immunized with ICIEAg. The difference of the amount of antibody against ICIEAg between AIMD guinea pig group and non-AIMD guinea pig group was not significant. Western blotting assay showed only the sera of AIMD guinea pig contained the antibodies against the specific antigens with the molecular of 68 000, 58 000, 42 000 and 28 000. CONCLUSIONS: ICIEAg contain many different components, the AIMD might only happen in the guinea pigs in which the special immunization against the main components that could induce this kind of disorder appeared. The inner ear antigens with molecular of 68 000, 58 000, 42 000 and 28 000 might be the main components inducing AIMD in guinea pigs.

[Expression of KISS-1 and GnRH in rat hypothalamus].

OBJECTIVE: To assay the expression of KiSS-1 and GnRH in the male rat hypothalamus at different developmental stages, and to explore the significance of KiSS-1 in sex development onset and normal reproduction regulation. METHODS: Expression analyses of KiSS-1 and GnRH genes were conducted in the rat hypothalamus at different developmental stages with RT-PCR and real time-PCR. The testosterone level was assayed by chemoluminescence technique. RESULTS: KiSS-1 mRNA rose gradually during sex development in the rat hypothalamus, highest at puberty and lowered a little at adulthood. KiSS-1 mRNA of the prepubertal, early pubertal, pubertal and adult rats was 1.7, 2.1, 3.5 and 2.0 times higher than that of the infantile rats respectively. The expression of GnRH and KiSS-1 correlated positively (r = 0.905, P < 0.05). But the activation of GnRH neuron was later than KiSS-1. The expression of GnRH was the highest in the puberty rats. GnRH mRNA of the prepubertal, early pubertal, pubertal and adult rats was 1.1, 1.94, 2.42 and 1.92 times higher than that of the infantile rats respectively. The level of testosterone in the adult rats was significantly higher than that at the earlier stage and was the highest at the adult stage. CONCLUSION: The expression of KiSS-1 correlates positively with that of GnRH. KiSS-1 may participate in the regulation of GnRH and is relevant to puberty onset and the regulation of reproduction function.