Macrophage migration inhibitory factor enhances lipopolysaccharide-induced fibroblast proliferation by inducing toll-like receptor 4.

BACKGROUND: Fibroblast proliferation is a common manifestation of chronic inflammatory diseases, including rheumatoid arthritis (RA), Crohn's disease and ulcerative colitis, etc. To alleviate patient suffering, the mechanism underlying fibroblast proliferation should be elucidated. METHODS: CCK-8 assay was used to assess the stimulatory effect of LPS and macrophage migration inhibitory factor (MIF) on fibroblast proliferation. Then, TLR4 expression on fibroblast cell membrane was carried out by confocal scanning microscopy. Finally, real-time fluorescent quantitative PCR and flow cytometry were applied to determine the expression of TLR4 after MIF challenge. RESULTS: LPS alone directly stimulated the fibroblast proliferation. In addition, MIF showed co-stimulatory effect on LPS-induced fibroblast proliferation. Interestingly, fibroblast overtly expressed TLR4 without stimulation. After MIF stimulation, real-time PCR showed TLR4 mRNA levels were increased by about 33% in the fibroblasts; in agreement, TLR4 expression on the fibroblast membrane was increased by about 20%, as shown by flow cytometry. CONCLUSIONS: These findings indicated MIF elevates TLR4 expression in fibroblast, enhancing LPS-induced cell proliferation.

Leydig cell transplantation restores androgen production in surgically castrated prepubertal rats.

Prepubertal testicular dysfunction and the subsequent development of hypogonadism affects an estimated one in 200 children worldwide. As the testosterone levels are dynamic during development and puberty, traditional hormone treatment regimens are often inadequate, thereby leaving associated physiological conditions unresolved. Therefore, we have investigated the potential therapeutic effect of mature Leydig cell transplantation for the treatment of prepubertal primary hypogonadism through the use of a surgically induced hypogonadistic rat model system. In the experiment, Leydig cells were surgically isolated from mature Sprague-Dawley rats and transplanted into prepubertal recipients. Serum testosterone levels and microscopic analysis of the stained testicular interstitium were compared with sham-treated controls, as well as with castrated and intact rats during sexual development. At 4 weeks post-implantation, serum testosterone was detectable in Leydig cell recipients, but not in surgical controls, and progressively increased as a function of time until reaching levels comparable with sexually mature males at 12 weeks post-implantation. Histological analysis revealed a high rate of Leydig cell survival as well as steroidogenic secretory activity. Therefore, we conclude that mature Leydig cell transplantation in prepubertal hypogonadism recipients has therapeutic potential in rats and merits further investigation for clinical application.

[Allotransplantation of Leydig cells increases serum testosterone in rats].

OBJECTIVE: To observe the changes of serum testosterone after allotransplantation of Leydig cells in rats. METHODS: Leydig cells were isolated from the testes of SD rats with the Percoll technique and serum testosterone of the receptors was determined once a month for 3 successive times. RESULTS: After allotransplantation of Leydig cells, the serum testosterone level of the receptors increased gradually, significantly higher at 3 months than that of the normal rats younger than 2 months old. CONCLUSION: Allotransplantation of Leydig cells has a promising application value in the treatment of male primary hypogonadism.

[Immunoregulation of vasoactive intestinal peptide on rat Leydig cells].

AIM: To study the regulation of immune function of rat Leydig cells by vasoactive intestinal peptide (VIP). METHODS: Rat Leydig cells were seperated and infected by UU, with or without the incubation with VIP. The expression of FasL on Leydig cells in different group was analysed by flow cytometry(FCM). The mRNA expression of IL-1, IL-6, TGF-beta and FasL of Leydig cells in different group was identified by RT-PCR. SD rats were infected by UU with or without the injection of VIP, and the testis tissnes of each group were har vested and observed under transmission electron microscope. RESULTS: When testis was infected by UU, VIP up-regulated the mRNA expression of IL-1, IL-6, and TGF-beta, and down-regulated the expression of FasL in vitro. In addition, there was significant difference in testis morphous of rats from different group. CONCLUSION: VIP could regulate the expression pattern of IL-1, IL-6, TGF-beta and FasL by Leydig cells, which may contribute to maintain immune privilege of the testis. VIP could regulate rat Leydig cell immune function.

[Influence of FasL overexpression in transgenic mice on the immune regulative function of Sertoli cell].

AIM: To study the influence of FasL overexpression in transgenic mice on the Sertoli cell immune response to testicular infection. METHODS: Ureaplasma urealyticum (UU) was directly injected into bladders of FasL transgenic mice and wild-type mice respectively, to mimic an ascending infection pathway. At week 1, 2 and 3 after injection, respectively, the mice were put to death to observe the pathological alterations in testis section. And at the same time the differences of FasL, TGF-beta, IL-1alpha and IL-6 expressions on Sertoli cells were compared by immunohistochemical staining between wild mice and transgenic mice before and after infection, respectively. The high-purified Sertoli cells were isolated from the testis tissue of wild-type mice, comparing apoptotic capability of Fas(+) Jurkat cells mediated by FasL(+) Sertoli cells of wild control and wild UU-infected groups. RESULTS: The pathological changes of testis tissue from transgenic mice were more serious as compared with wild-type mice and the model of cytokines secreted by sertoli cells was distinctive between the two kinds of mice. The UU-infected Sertoli cells increased Fas(+) Jurkat cell apoptosis. CONCLUSION: FasL overexpression can influence the cytokine's secretion in the process of anti-infection immunity and further affects the immune balance of testis locality. Not all FasL over expression is benefit to body's anti-infection immune response.