The Role of Innate Immunity in Osteoarthritis and the Connotation of "Immune-joint" Axis: A Narrative Review

Osteoarthritis (OA) is a degenerative disease that results in constriction of the joint space due to the gradual deterioration of cartilage, alterations in subchondral bone, and synovial membrane. Recently, scientists have found that OA involves lesions in the whole joint, in addition to joint wear and tear and cartilage damage. Osteoarthritis is often accompanied by a subclinical form of synovitis, which is a chronic, relatively low-grade inflammatory response mainly mediated by the innate immune system. The "immune-joint" axis refers to an interaction of an innate immune response with joint inflammation and the whole joint range. Previous studies have underestimated the role of the immune-joint axis in OA, and there is no related research. For this reason, this review aimed to evaluate the existing evidence on the influence of innate immune mechanisms on the pathogenesis of OA. The innate immune system is the body's first line of defense. When the innate immune system is triggered, it instantly activates the downstream inflammatory signal pathway, causing an inflammatory response, while also promoting immune cells to invade joint synovial tissue and accelerate the progression of OA. We have proposed the concept of the "immune-joint" axis and explored it from two aspects of Traditional Chinese Medicine (TCM) theory and modern medical research, such as the innate immunity and OA, macrophages and OA, complement and OA, and other cells and OA, to enrich the scientific connotation of the "immune-joint" axis.

Autogenous fibula head transplantation for aneurysmal bone cyst of distal radius: A case report followed up for 7 years

RATIONALE

Aneurysmal bone cyst (ABC) is a rare primary or secondary tumor that usually occurs in young women aged between 10 and 20 years, mostly in the long tubular bone and spine. However, there are no definite standards for its clinical treatment. To our knowledge, this is the first report of a young female patient with distal radius ABC who was successfully treated with tumor resection and autogenous fibular head transplantation.

PATIENT CONCERNS

A 28-year-old married Chinese young woman presented to our hospital with swelling and pain in her right wrist for 2 years and aggravation of wrist movement restriction for 1 week.

DIAGNOSES

Pathological biopsy confirmed ABC.

INTERVENTIONS

We performed a pathological examination of the tumor on the right wrist and preliminarily confirmed the diagnosis of ABC. The right wrist joint was reconstructed by total surgical resection of the ABC tumor in the right wrist joint and autogenous fibular head transplantation.

OUTCOMES

During follow-up within 7 years, good right wrist function was confirmed. The tumor did not recur, the swelling of the right wrist disappeared, the joint pain and limitation of movement significantly improved, and the function of the right wrist was not impaired in daily activities. Radiography showed that the fracture had healed.

LESSONS

Our results suggest that autofibular head transplantation is an effective treatment for reconstruction of wrist function in adult patients with ABC of the distal radius.

Prebiotics Alleviates Cartilage Degradation and Inflammation in Post-traumatic Osteoarthritis Mice by Modulating the Gut Barrier and Fecal Metabolomics

Osteoarthritis (OA) is a degenerative joint disease characterized by articular cartilage degeneration, subchondral bone sclerosis, synovial hyperplasia and as the main pathological manifestations. This study aims to investigate the protective...

Zhuifeng tougu capsules inhibit the TLR4/MyD88/NF-κB signaling pathway and alleviate knee osteoarthritis: In vitro and in vivo experiments

Background: Knee osteoarthritis (KOA), a chronic degenerative disease, is mainly characterized by destruction of articular cartilage and inflammatory reactions. At present, there is a lack of economical and effective clinical treatment. Zhuifeng Tougu (ZFTG) capsules have been clinically approved for treatment of OA as they relieve joint pain and inflammatory manifestations. However, the mechanism of ZFTG in KOA remains unknown.

Purpose: This study aimed to investigate the effect of ZFTG on the TLR4/MyD88/NF-κB signaling pathway and its therapeutic effect on rabbits with KOA.

Study design:In vivo, we established a rabbit KOA model using the modified Videman method. In vitro, we treated chondrocytes with IL-1β to induce a pro-inflammatory phenotype and then intervened with different concentrations of ZFTG. Levels of IL-1β, IL-6, TNF-α, and IFN-γ were assessed with histological observations and ELISA data. The effect of ZFTG on the viability of chondrocytes was detected using a Cell Counting Kit-8 and flow cytometry. The protein and mRNA expressions of TLR2, TLR4, MyD88, and NF-κB were detected using Western blot and RT-qPCR and immunofluorescence observation of NF-κB p65 protein expression, respectively, to investigate the mechanism of ZFTG in inhibiting inflammatory injury of rabbit articular chondrocytes and alleviating cartilage degeneration.

Results: The TLR4/MyD88/NF-κB signaling pathway in rabbits with KOA was inhibited, and the levels of IL-1β, IL-6, TNF-α, and IFN-γ in blood and cell were significantly downregulated, consistent with histological results. Both the protein and mRNA expressions of TLR2, TLR4, MyD88, NF-κB, and NF-κB p65 proteins in that nucleus decreased in the ZFTG groups. Moreover, ZFTG promotes the survival of chondrocytes and inhibits the apoptosis of inflammatory chondrocytes.

Conclusion: ZFTG alleviates the degeneration of rabbit knee joint cartilage, inhibits the apoptosis of inflammatory chondrocytes, and promotes the survival of chondrocytes. The underlying mechanism may be inhibition of the TLR4/MyD88/NF-kB signaling pathway and secretion of inflammatory factors.

The effects of Jiawei Duhuo Jisheng mixture on Wnt/β-catenin signaling pathway in the synovium inflamed by knee osteoarthritis: An in vitro and in vivo experiment

ETHNOPHARMACOLOGICAL RELEVANCE

Knee osteoarthritis (KOA) is one of the common age-degenerative diseases. Recent studies have demonstrated that the pathogenesis of KOA is closely related to synovial lesions. Jiawei Duhuo Jisheng mixture (JDJM) has shown great potential in the treatment of KOA. However, the effect and mechanism of JDJM on synovial lesions of KOA remain unclear.

AIM OF THE STUDY

The regulatory effect of JDJM on the Wnt/β-catenin signaling pathway in KOA inflamed synovium was studied via in vitro and in vivo experiments, respectively.

MATERIALS AND METHODS

For the in vitro experiment, fibroblasts were isolated from the rabbit synovium with KOA. The fibroblasts were grouped as follows: the vehicle group was given 0.5% FBS; the inhibitor group was treated with 0.5% volume fraction of XAV939; the normal serum groups and JDJM serum groups were treated with 5%, 10%, and 20% volume fractions of normal serum and JDJM-containing serum. The expression levels of Wnt3a, β-catenin, Cyclin D1, metalloproteinase-7(MMP-7) and cyclooxygenase-2(COX-2) were detected by different assays 48 and 72 h after the intervention. For the in vivo experiment, the rabbit KOA model was prepared using the improved Hulth modeling method, whereby all rabbits were randomly divided into normal control, model control, positive control, and traditional Chinese medicine (TCM) groups. The expression levels of Wnt3a, β-catenin, Cyclin D1, MMP-7 and COX-2 were detected by different assays in the 2, 4, and 8 weeks of treatment.

RESULTS

In the two test results of in vitro experiments, the normal serum group was compared with the JDJM-containing serum group with the same volume fraction, demonstrating that mRNA transcription and protein expression levels of Wnt3a, β-catenin, Cyclin D1, MMP-7, and COX-2 in the latter decreased (P < 0.05), with more pronounced effects observed in the group treated with 20% volume fraction of JDJM serum. Compared with the inhibitor group, there was no significant difference (P > 0.05) in the mRNA transcription and protein expression levels, i.e., Wnt3a, β-catenin, Cyclin D1, and MMP-7 were observed in the JDJM serum groups, except for a significant decrease (P < 0.05) in the level of mRNA transcription and protein expression of COX-2. Based on the in vivo experiment, compared to the model control group, articular cartilage, synovial hyperplasia, and the inflammatory reaction of the TCM group at different treatment times were significantly improved. The mRNA transcription level of Wnt3a, β-catenin, Cyclin D1, MMP-7 and COX-2 detected by RT-qPCR and the protein expression level of Wnt3a, β-catenin, Cyclin D1, MMP-7 and COX-2 detected by Western blot were significantly reduced (P < 0.05), and the effect was more evident at the eighth week.

CONCLUSION

JDJM can regulate the synovial Wnt/β-catenin signaling pathway in KOA models, reduce the mRNA transcription and protein expression levels of Wnt3a, β-catenin, Cyclin D1, MMP-7, and COX-2 in the synovium, thus inhibiting synovial inflammation and protecting articular cartilage, which could be the key mechanism of action in treating this disease.

Baicalein Alleviates Osteoarthritis Progression in Mice by Protecting Subchondral Bone and Suppressing Chondrocyte Apoptosis Based on Network Pharmacology

As life expectancy increases, Osteoarthritis (OA) is becoming a more frequently seen chronic joint disease. The main characteristics of OA are loss of articular cartilage, subchondral bone sclerosis, and synovial inflammation. Baicalein (Bai), a traditional Chinese medicine extracted from Scutellaria baicalensis Georgi, has been demonstrated to exert notable anti-inflammatory effects in previous studies, suggesting its potential effect in the treatment of OA. In this study, we first predicted the action targets of Bai, mapped target genes related to OA, identified potential anti-OA targets for Bai, performed gene ontology (GO) enrichment, and KEGG signaling pathway analyses of the action targets, and analyzed the molecular docking of key Bai targets. Additionally, the effect and potential mechanism of Bai against OA were verified in mouse knee OA models induced by destabilized medial meniscus (DMM) surgery. GO and KEGG analyses showed that 19 anti-OA targets were mainly involved in the response to oxidative stress, the response to hypoxia and apoptosis, and the PI3K-Akt and p53 signaling pathways. Molecular docking results indicated that BAX, BCL 2, and Caspase 3 enriched in the apoptotic signaling pathway have high binding affinity with Bai. Validation experiments showed that Bai can significantly attenuate the loss of articular cartilage (OARSI score), suppress synovial inflammation (synovitis score), and ameliorate subchondral bone resorption measured by micro-CT. In addition, Bai notably inhibited the expression of apoptosis-related proteins in articular cartilage (BAX, BCL 2, and Caspase 3). By combining network pharmacology with experimental validation, our study identifies and verifies the importance of the apoptotic signaling pathway in the treatment of OA by Bai. Bai may have promising application and potential therapeutic value in OA treatment.

Acupuncture combined with TCM bonesetting in the treatment of distal radius fractures: A protocol for systematic review and meta-analysis

BACKGROUND

Acupuncture combined with traditional Chinese medicine (TCM) bonesetting is an effective and more acceptable treatment method for distal radius fractures; this study aims to evaluate the clinical efficacy and other relevant factors of it compared with western medicine therapy such as operation.

METHODS

Databases CNKI, Wanfang, VIP, SinoMed, and PubMed were searched for the current study. The retrieval time was from the establishment to November 14, 2021. Literature quality was evaluated according to the bias risk assessment criteria of Cochrane Collaboration network. RevMan 5.3 and Stata 12.0 were used to perform this research.

RESULTS

This study will appraise the effectiveness and advantages of acupuncture combined with TCM bonesetting for distal radius fractures in terms of excellent and good rate, length of stay, hospitalization expenses, complication, and other factors.

CONCLUSION

This study provides reliable evidence-based support for the clinical efficacy and advantages of acupuncture combined with TCM bonesetting for distal radius fractures.

OSF REGISTRATION DOI

10.17605/OSF.IO/BUPE8.

Emerging roles of exosomal miRNAs in diabetes mellitus

Exosomes are small extracellular vesicles 40-160 nm in diameter that are secreted by almost all cell types. Exosomes can carry diverse cargo including RNA, DNA, lipids, proteins, and metabolites. Exosomes transfer substances and information between cells by circulating in body fluids and are thus involved in diverse physiological and pathological processes in the human body. Recent studies have closely associated exosomal microRNAs (miRNAs) with various human diseases, including diabetes mellitus (DM), which is a complex multifactorial metabolic disorder disease. Exosomal miRNAs are emerging as pivotal regulators in the progression of DM, mainly in terms of pancreatic β-cell injury and insulin resistance. Exosomal miRNAs are closely associated with DM-associated complications, such as diabetic retinopathy (DR), diabetic nephropathy (DN), and diabetic cardiomyopathy (DCM), etc. Further investigations of the mechanisms of action of exosomal miRNAs and their role in DM will be valuable for the thorough understanding of the physiopathological process of DM. Here, we have summarized recent findings regarding exosomal miRNAs associated with DM to provide a new strategy for identifying potential diagnostic biomarkers and drug targets for the early diagnosis and treatment, respectively, of DM.

The Role of Non-coding RNAs in Diabetic Nephropathy-Related Oxidative Stress

Diabetic nephropathy (DN) is one of the main complications of diabetes and the main cause of diabetic end-stage renal disease, which is often fatal. DN is usually characterized by progressive renal interstitial fibrosis, which is closely related to the excessive accumulation of extracellular matrix and oxidative stress. Non-coding RNAs (ncRNAs) are RNA molecules expressed in eukaryotic cells that are not translated into proteins. They are widely involved in the regulation of biological processes, such as, chromatin remodeling, transcription, post-transcriptional modification, and signal transduction. Recent studies have shown that ncRNAs play an important role in the occurrence and development of DN and participate in the regulation of oxidative stress in DN. This review clarifies the functions and mechanisms of ncRNAs in DN-related oxidative stress, providing valuable insights into the prevention, early diagnosis, and molecular therapeutic targets of DN.

Long noncoding RNA DLEU2 affects the proliferative and invasive ability of colorectal cancer cells

Emerging evidence indicates that long noncoding RNAs (lncRNAs) are closely associated with colorectal cancer (CRC) tumorigenesis. One example is lncRNA Deleted in Lymphocytic Leukemia 2 (DLEU2). However, how DLEU2 contributes to CRC is still poorly understood. This study sought to investigate the effects of DLEU2 on CRC pathogenesis, and the underlying mechanism involved. Using a quantitative real-time polymerase chain reaction (qRT-PCR) assay, we demonstrated that the expression levels of DLEU2 in 45 pairs of CRC tissues were higher than those in the corresponding normal colon mucosal tissues. In addition, CRC patients with high DLEU2 expression levels exhibited poor overall survival (OS) and recurrence-free survival (RFS), as determined by analyses and measurements from the GEO and GEPIA databases. When DLEU2 was silenced using short interfering RNA (siRNA) in CRC cell line, the results demonstrated that DLEU2 silencing suppressed CRC cell tumorigenesis in vitro, which was associated with decreased expression of cyclin dependent kinase 6(CDK6), ZEB1, and ZEB2 as well as enhancing the expression of Cyclin-dependent kinase inhibitor 1A (CDKN1A). Taken together, the results of this study suggested that DLEU2 may play critical roles in the progression of CRC and may serve as a prognostic biomarker for CRC.

Studies on the therapeutic effects of three TCM methods on steroid-induced osteonecrosis of femoral head

Purpose: To determine the therapeutic effects of kidney yang-tonifying, blood-activating and phlegmeliminating methods on steroid-induced osteonecrosis of femoral head (SONFH), and their mechanisms of action.Methods: A rabbit model of SONFH was established. Six rabbit groups were used: control, SONFH (given normal saline); tongluo shenggu group, kidney-tonifying group, blood-activating group, and phlegm--eliminating group, which received tongluo shenggu capsule (0.28 g/kg/day), yougui yin (YGY, 2.52 g/kg/day), taohong siwu decoction (TSD, 2.38 g/kg/day) and linggui zhugan decoction (LZD,1.54 g/kg/day), respectively, for 8 weeks. The following serum indices were assayed on the 2nd, 4th and 8th weeks: total cholesterol, triglycerides, thromboxane B2 (TXB2), 6-keto-PGF1α, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-Β ligand (RANKL). At the end of the 8th week, mRNA levels of OPG, BMP-2 and VEGF were assayed using real-time fluorescent quantitative polymerase chain reaction (RTF-qPCR).Results: Serum OPG in the kidney-tonifying group was increased, while its RANKL was decreased on the 2nd week, but these parameters, along with mRNA of OPG and BMP-2, reached normal levels at the 8th week (p <0.05). The TXB2 of blood-activating group was decreased, while its 6-keto-PGF1 level was increased at the 2nd week, but both of them attained normal levels at the 8th week, along with VEGF mRNA. Serum total cholesterol, triglycerides and TXB2 in the phlegm-eliminating group were decreased, while its 6-keto-PGF1α was increased at the 2nd week, but the levels of serum total cholesterol and triglycerides were normalized at the 8th week (p <0.05). Histological examination showed increases in bone trabeculae and bone marrow cells, while the proliferation of fat cells was decreased in kidney-tonifying, blood-activating and phlegm-eliminating groups.Conclusion: These findings suggest that the therapeutic effects of the three different TCM methods on SONFH involve different mechanisms. Keywords: Steroid-induced osteonecrosis, Femoral head, Yougui yin, Taohong siwu, Linggui zhugan decoction, Kidney-tonifying yang, Phlegm

CircRNA cPWWP2A: an emerging player in diabetes mellitus

Circular RNAs(CircRNAs), a new class of non-coding RNAs, possess significant capabilities of gene regulation and are disrupted in various diseases, including diabetes mellitus (DM). However, the underlying mechanism of CircRNAs in DM and diabetic complications remains illusive. A recent study published by Liu et al. (Proc Natl Acad Sci USA 116:7455-7464, 2019) shown that a novel diabetic retinopathy (DR)-associated CircRNA cPWWP2A, which could act as a competing endogenous RNA interacting with miR-579 to promote the DR-induced retinal vascular dysfunction through up-regulating the expression of Angiopoietin 1, Occludin, and SIRT1. Their findings may provide new insight into the potential use of CircRNA cPWWP2A for the targeted therapy of DR. However, those promising findings may need to be further evaluated detailedly for the following reason. (1) This study doesn't well clarify why the most significantly up-regulated CircRNA mmu _circ_0000254 the fold change of which is 160.581 is excluded,while the cPWWP2A the fold change of which is only 3.487 is chosen. (2) It is difficult to conclude that cPWWP2A competing with miR-579 only by the analysis of colocalization in pericytes.

Up-regulation of LINC00467 promotes the tumourigenesis in colorectal cancer

Recent studies have reported that long non-coding RNAs (lncRNAs) are associated with the tumourigenesis of colorectal cancer (CRC); however, several of these are yet to be identified and characterised. In this study, we report a novel lncRNA, LINC00467, which was significantly up-regulated in CRC; we investigated its function and mechanism in CRC. Our study demonstrated that LINC00467 levels in 45 pairs of CRC tissues were higher than those in the corresponding normal colon mucosal tissues. We used the Gene Expression Omnibus (GEO) and Gene Expression Profiling Interactive Analysis (GEPIA) databases for the analysis and measurement of clinical samples, and observed that the CRC patients with high LINC00467 expression levels showed poor overall survival (OS) and recurrent-free survival (RFS) rates. Furthermore, following the short interfering RNA (siRNA) knockdown of LINC00467 in the CRC cell line, the results demonstrated that LINC00467 suppresses the proliferation, invasion and metastasis of CRC cells in vitro. Moreover, its molecular mechanism of LINC00467 decreased the expression of Cyclin D1, Cyclin A1, CDK2, CDK4 and Twist1 as well as enhanced the expression of E‑cadherin. Collectively, these findings suggest that LINC00467 may be crucial in the progression and development of CRC, and may serve as a potential therapeutic target for CRC patients.

Hypermethylation and aberrant expression of Wnt-antagonist family genes in gastric cardia adenocarcinoma

The canonical Wnt signalling pathway plays a key role during embryogenesis and pathogenesis of various types of tumors. Recently, several studies have shown that the promoter hypermethylation of Wnt-antagonist genes, including sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1 and Dkk-3, have been certified to contribute to the tumorigenesis of several cancers. The aim of this study was to investigate the promoter methylation of Wnt-antagonist genes in gastric cardia adenocarcinoma (GCA) and corresponding adjacent non-cancerous tissues, and to establish the possible relationship between DNA methylation status and the pathogenesis of GCA. MSP, RT-PCR methods were applied respectively to examine the CpG methylation of the Wnt-antagonist genes and its mRNA expression in tumors and corresponding non-cancerous tissues, and immunohistochemistry method was used to determine protein expression of β-catenin(the key factor of the Wnt signalling pathway) and cyclin D1(the target gene of this pathway). The frequency of promoter methylation of sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1 and Dkk-3 genes in GCA tumor tissues were 78.7%(74/94), 76.6%(72/94), 70.2%(66/94), 77.1%(73/94), 61.7%(58/94) and 21.3%(20/94), respectively, which were significantly higher than those in adjacent non-cancerous tissues. Furthermore, the frequencies of silenced mRNA expression of these six genes in GCA tumor tissues were significantly higher than those in adjacent non-cancerous tissues. Methylation levels of these six genes were all correlated with loss of mRNA expression. The ectopic expression of β-catenin and cyclin D1 was significantly more frequent in GCA tumor tissues than that in adjacent non-cancerous tissues and correlated with each Wnt-antagonist genes hypermethylation status. Epigenetic silencing of Wnt-antagonist genes expression by promoter hypermethylation may play an important role in gastric cardia adenocarcinoma.

Detection of promoter hypermethylation of the CpG island of E-cadherin in gastric cardiac adenocarcinoma

AIM

Abnormal hypermethylation of CpG islands associated with tumor suppressor genes can lead to transcriptional silencing in neoplasia. The aim of this study was to investigate the promoter methylation and expression of E-cadherin gene in gastric cardiac adenocarcinoma (GCA).

METHODS

A nested MSP approach, immunohistochemistry method and RT-PCR were used respectively to examine the methylation status of the 5' CpG island of E-cadherin, its protein expression and mRNA expression in tumors and corresponding normal tissues.

RESULTS

E-cadherin was methylated in 63 of 92 (68.5%) tumor specimens, which was significantly higher than that in corresponding normal tissues (P<0.001). Methylation frequencies of stage III and IV tumor tissues was significantly higher than that in stage I and II tumor tissues (P = 0.01). Methylation status of poor differentiation group was significantly higher than moderate and poor-moderate differentiation groups (P<0.01). By immunostaining 51 of 92 tumor tissues demonstrated heterogeneous, positive immunostaining of tumor tissues (44.6%), significantly different from matched normal tissues (P<0.001). Positive immunostaining of stage III and IV tumor tissues was significantly lower than stage I and II tumor tissues (P<0.01). Poor differentiation group was also significantly lower than moderate and poor-moderate differentiation groups (P<0.05). 80 percent of tumor tissues with E-cadherin gene methylated showed inactivated mRNA expression.

CONCLUSIONS

High methylation status of the 5' CpG island of E-cadherin gene may be one of the mechanisms in the development of gastric cardiac adenocarcinoma.

[Expression of vascular endothelial growth factor and tumor angiogenesis correlates with biological behaviors of nasopharyngeal carcinoma]

OBJECTIVE

To study the correlation between tumor angiogenesis and biological behaviors of nasopharyngeal carcinoma(NPC).

METHOD

Angiogenesis was assessed by the microvessel dinsity(MVD) and expression of vascular endothelial growth factor(VEGF) was detected using immunohistochemical S-P method. Paraffin-embedded specimens from 65 patients with NPC and 15 with benign nasopharyngeal tumors, 15 with tumor-free nasopharyngeal mucosac were detected.

RESULT

Expressions of VEGF and MVD in NPC group were higher than that of nonmetastic carcinoma group. The relationship between expressions of VEGF and MVD and the clinical staging present statistic significance.

CONCLUSION

MVD and expression of VEGF are highly correlated with biological behaviors of NPC, which may serve as a parameter for determining tumor biological metastatic potential and prognosis. Angiogenesis inhibitors might be helpful in preventing NPC from metastasis.

Nerve growth factor promotes collateral sprouting of cholinergic fibers in the septohippocampal cholinergic system of aged rats with fimbria transection

Nerve growth factor (NGF) was injected intraventricularly into aged (24 months) rats with unilateral fimbria transection. Controls received intraventricular injections of cytochrome c. A quantitative analysis of acetylcholinesterase (AChE)-positive fibers was used to evaluate whether the NGF treatment can stimulate regeneration and reinnervation of the cholinergic axons in the septohippocampal system of aged rats with fimbria transection. A marked increase in the density of AChE-positive fibers was observed in the lateral septum, the dorsal fornix and the dorsal hippocampus of the NGF-treated animals, as compared to the controls. In the lateral septum, the increase was observed in the 2-month NGF-treated animals but not in the 15-day NGF-treated animals. In the dorsal fornix at the level of the dorsal hippocampus, the increase was observed on both the lesioned and unlesioned sides of both the 15-day and 2-month NGF-treated animals. In the denervated (lesioned side) hippocampus, the increase took place in the dorsal hippocampus but not in the ventral hippocampus of both the 15-day and 2-month NGF-treated animals. There was no recovery of AChE-positive fibers on the lesioned side of the fimbria distal to the lesion site even in the 2-month NGF-treated animals. These results demonstrate that intraventricular injections of NGF can stimulate collateral sprouting of intact cholinergic axons in the septohippocampal system and promote cholinergic reinnervation of the denervated hippocampus of aged rats with fimbria transection.