Impact of carbimazole combined with vitamin E on testicular injury induced by experimental hyperthyroidism in adult albino rats: oxidative/inflammatory/apoptotic pathways.

Thyroid hormones play essential roles in spermatogenesis, but their effects on infertile males remain poorly understood. This study aimed to evaluate the impact of combining carbimazole (CBZ) with vitamin E (VE) on testicular injury induced by experimental hyperthyroidism in adult albino rats, focusing on oxidative, inflammatory, and apoptotic pathways. In this experimental study, 64 adult male albino Wistar rats were divided into eight groups: Group I (control-untreated), Group II (CBZ-control), Group III (VE-control), Group IV (CBZ + VE-control), Group V (levothyroxine-induced testicular injury), Group VI (levothyroxine + CBZ-treated), Group VII (levothyroxine + VE-treated), and Group VIII (levothyroxine + CBZ + VE-treated). The study was conducted in the Faculty of Medicine, Suez Canal University (Ismailia, Egypt). After cervical decapitation, both testes and epididymis were examined histopathologically and immunohistochemically. Significant differences were observed among groups concerning malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT; all P < 0.001). Polymerase chain reaction analysis showed significant differences in tumor necrosis factor-α (TNF- α ), interleukin-10 (IL-10), Bcl-2-associated X protein (BAX), B-cell lymphoma 2 protein (Bcl2), p53, Caspase-3, Caspase-8, Caspase-9, and nuclear factor-kappa B (NF- κ B) mRNA levels (all P < 0.001). Hyperthyroid group treated with CBZ alone (Group VI) exhibited testicular side effects, affecting seminiferous tubules and spermatogenesis. However, the Group VIII showed improved spermatogenesis and a decrease in testicular side effects. The addition of VE to the treatment of hyperthyroid rats with CBZ reduced testicular side effects and seminiferous tubular affection when potentially improving spermatogenesis. Further research is needed to elucidate the underlying mechanisms fully.

Betanin improves motor function and alleviates experimental Parkinsonism via downregulation of TLR4/MyD88/NF-κB pathway: Molecular docking and biological investigations.

Parkinson's disease (PD) is a progressive neuroinflammatory and degenerative disease. In this study, we investigated the neuroprotective action of betanin in the rotenone-induced Parkinson-like mice model. Twenty-eight adult male Swiss albino mice were divided into four groups: Vehicle, Rotenone, Rotenone + Betanin 50 mg/kg, and Rotenone + Betanin 100 mg/kg. Parkinsonism was induced by subcutaneous injection of 9 doses of rotenone (1 mg/kg/48 h) plus betanin at 50 and 100 mg/kg/48 h in rotenone + betanin groups for twenty days. Motor dysfunction was assessed after the end of the therapeutic period using the pole, rotarod, open-field, grid, and cylinder tests. Malondialdehyde, reduced glutathione (GSH), Toll-like receptor 4 (TLR4), myeloid differentiation primary response-88 (MyD88), nuclear factor kappa- B (NF-κB), neuronal degeneration in the striatum were evaluated. In addition, we assessed the immunohistochemical densities of tyrosine hydroxylase (TH) in Str and in substantia nigra compacta (SNpc). Our results showed that rotenone remarkably decreased (results of tests), increased decreased TH density with a significant increase in MDA, TLR4, MyD88, NF-κB, and a decrease in GSH (p < 0.05). Treatment with betanin significantly results of tests), increased TH density. Furthermore, betanin significantly downregulated malondialdehyde and improved GSH. Additionally, the expression of TLR4, MyD88, and NF-κB was significantly alleviated. Betanin's powerful antioxidative and anti-inflammatory properties can be related to its neuroprotective potential as well as its ability to delay or prevent neurodegeneration in PD.

α-Hederin Saponin Augments the Chemopreventive Effect of Cisplatin against Ehrlich Tumors and Bioinformatic Approach Identifying the Role of SDF1/CXCR4/p-AKT-1/NFκB Signaling.

Stromal cell-derived factor-1 (SDF1) and its C-X-C chemokine receptor type 4 receptor (CXCR4) are significant mediators for cancer cells' proliferation, and we studied their expression in Ehrlich solid tumors (ESTs) grown in mice. α-Hederin is a pentacyclic triterpenoid saponin found in Hedera or Nigella species with biological activity that involves suppression of growth of breast cancer cell lines. The aim of this study was to explore the chemopreventive activity of α-hederin with/without cisplatin; this was achieved by measuring the reduction in tumor masses and the downregulation in SDF1/CXCR4/pAKT signaling proteins and nuclear factor kappa B (NFκB). Ehrlich carcinoma cells were injected in four groups of Swiss albino female mice (Group1: EST control group, Group2: EST + α-hederin group, Group3: EST + cisplatin group, and Group4: EST+α-hederin/cisplatin treated group). Tumors were dissected and weighed, one EST was processed for histopathological staining with hematoxylin and eosin (HE), and the second MC was frozen and processed for estimation of signaling proteins. Computational analysis for these target proteins interactions showed direct-ordered interactions. The dissected solid tumors revealed decreases in tumor masses (~21%) and diminished viable tumor regions with significant necrotic surrounds, particularly with the combination regimens. Immunohistochemistry showed reductions (~50%) in intratumoral NFκß in the mouse group that received the combination therapy. The combination treatment lowered the SDF1/CXCR4/p-AKT proteins in ESTs compared to the control. In conclusion, α-hederin augmented the chemotherapeutic potential of cisplatin against ESTs; this effect was at least partly mediated through suppressing the chemokine SDF1/CXCR4/p-AKT/NFκB signaling. Further studies are recommended to verify the chemotherapeutic potential of α-hederin in other breast cancer models.

The GSTP1/MAPKs/BIM/SMAC modulatory actions of nitazoxanide: Bioinformatics and experimental evidence in subcutaneous solid Ehrlich carcinoma-inoculated mice.

AIMS: Ehrlich ascites carcinoma and its subcutaneous inoculated solid tumour form (SEC) are reliable models for chemotherapeutic molecular targets exploration. Novel chemotherapeutic approaches are identified as molecular targets for intrinsic apoptosis, like the modulation of the second mitochondria-derived activator of caspases (SMAC). SMAC is a physiological substrate of mitogen-activated protein kinases (MAPKs). Glutathione-S-transferase P1 (GSTP1) and its close association with MAPKs play an important role in malignant cell proliferation, metastasis, and resistance to chemotherapeutics. Nitazoxanide (NTZ) is an emerging cancer therapy and its targeted GSTP1 evidence remains a knowledge need. MAIN METHODS: In the present mice-established SEC, the chemotherapeutic roles of oral NTZ (200 mg/kg/day) and 5-fluorouracil (5-FU; 20 mg/kg/day, intraperitoneally) regimens were evaluated by measuring changes in tumour mass, the tumour MAPKs, cytochrome c, Bcl-2 interacting mediator of cell death (BIM), and SMAC signalling pathway in addition to its molecular downstream; caspases 3 and 9. KEY FINDINGS: Computational analysis for these target protein interactions showed direct-ordered interactions. After individual therapy with NTZ and 5-FU regimens, the histological architecture of the extracted tumour discs revealed decreases in viable tumour regions with significant necrosis surrounds. These findings were consistent with gross tumour sizes. Each separate regimen lowered the remarkable GSTP1 and elevated the low MAPKs expressions, cytochrome c, BIM, SMAC, and caspases 3, and 9 in EST tissues. SIGNIFICANCE: The chemotherapeutic activity of NTZ in SEC was proven. Additionally, NTZ possesses a SMAC modulatory activity that, following thorough research, should be taken into consideration as a chemotherapeutic approach in solid tumours.

Vismodegib, a sonic hedgehog signalling blockade, ameliorates ovalbumin and ovalbumin/lipopolysaccharide-induced airway inflammation and asthma phenotypical models.

AIMS: Asthmatics exhibit clinical fluctuations between manageable and treatment-resistant phenotypes as a worldwide socioeconomic health burden. Sonic Hedgehog (Shh) genes mediate regulatory pulmonary cell renewal in adults and contribute to the pathogenesis of high phenotypic asthma which depends mainly on T helper-2 (Th-2) cells and related cytokines. However, the exact pathophysiological roles of Shh molecular signalling in the Th-17-dependent low phenotypic allergic airway inflammation and asthma are not evidenced previously. MAIN METHODS: Ovalbumin (OVA) and OVA/lipopolysaccharide (LPS)-sensitized and challenged BALB/c mice were enrolled currently to assess the Shh signalling proteins. Furthermore, the effects of vismodegib, a Smo inhibitor, on the modulation of Shh signalling were compared to dexamethasone. The asthma phenotypes were confirmed by serum total immunoglobulin-E (IgE), bronchoalveolar lavage (BAL) fluid white blood cell counts, lung interleukins, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-ß1, and histopathological changes, and scoring. KEY FINDINGS: Mice challenged with OVA or OVA/LPS showed upregulated lung Shh, patched (Ptch1), smoothened (Smo), and Gli1 proteins. Vismodegib in the two experimental phenotypes of asthma showed reduced airway inflammation and remodelling. Additionally, vismodegib reduced the eosinophilia and neutrophilia reported in high and low asthma types, respectively. Moreover, vismodegib and dexamethasone exhibited negative feedback control throughout the enhanced Shh signalling cascades, including Shh, Ptch1, and Gli1 in several asthma models. SIGNIFICANCE: In conclusion, Shh signalling partially elucidates the OVA/LPS-challenged mice with severe asthma, which proposes a new promising molecular therapeutic target. Furthermore, Smo inhibition by vismodegib has therapeutic potential in both experimental eosinophilic and neutrophilic allergic airway diseases.

Metformin alleviates the dysregulated testicular steroidogenesis and spermatogenesis induced by carbimazole in levothyroxine-primed rats.

Most of the published experiments about carbimazole (CMZ)-induced testicular injury are constructed in normal healthy animals, which lakes the translational identification. Despite metformin (MET) having advantageous effects on injured testicles, its impact on thyroid function is arguable. In the current levothyroxine (LT4)/CMZ model, Wistar rats were primed by LT4 for sixty days. CMZ was then given individually or simultaneously with different doses of MET, 100, 200, and 400 mg, daily for thirty days. Serum was assessed for thyroid profile panel, sex hormones, and gonadotropin levels. Testicular tissues were examined for steroidogenesis, spermatogenesis, inflammation, and apoptosis. Histopathology of thyroid and testes were examined, besides thyroidal nuclear factor (NF)-kB expression. MET in a dose-response manner improved the LT4/CMZ-induced testicular toxicity by increasing the steroidogenic acute regulatory protein (StAR), and 17-ß-hydroxysteroid dehydrogenase (17ßHSD) activities, the proliferating cell nuclear antigen (PCNA), sperm count and motility, sex hormones, and gonadotropin levels. MET-400 mg markedly decreased the elevated NF-kB expressions, tumour necrosis factor (TNF)-α, caspase-3, and BAX, and increased BCL-2. LT4/CMZ could be used as translational animal modelling. MET displayed a dose-dependent ameliorative effect on the LT4/CMZ model without significant harmful effects on thyroid functions. MET-testicular protective roles in diabetics with thyroidal diseases should be explored.

Autophagy modulation by irbesartan mitigates the pulmonary fibrotic alterations in bleomycin challenged rats: Comparative study with rapamycin.

AIMS: In pulmonary fibrosis, autophagy handles the maintenance of alveolar epithelial cells, prevents epithelial-mesenchymal transition (EMT), and controls collagen turnover. The mammalian target of rapamycin (mTOR) and its translational-dependent proteins are essential regulators of autophagy. Irbesartan (IRB) has earlier ameliorative effects in experimental pulmonary fibrosis. The current study aimed to explore therapeutic autophagy-modulated pulmonary fibrotic changes by IRB versus rapamycin (RAPA) in bleomycin (BLM)-challenged rats. MATERIALS AND METHODS: A single intratracheal BLM dose at day (0), IRB in different doses (10, 20, and 40 mg/kg) or RAPA (2.5 mg/kg) was given daily for 14 continuous days. KEY FINDINGS: IRB significantly diminished the fibrotic lung scores. Pulmonary levels of transforming growth factor (TGF)-ß1 and hydroxyproline exhibited marked attenuation in IRB (40 mg/kg)-treated rats compared to other treated groups. IRB (40 mg/kg) was not significantly different from RAPA. It downregulated the fibrotic lung phosphorylated mammalian target of rapamycin (p-mTOR) levels and augmented lung Unc-51-like autophagy activating kinase 1 (ULK1), LC3-I and LC3-II more than IRB (10 and 20 mg/kg)-treated fibrotic groups. SIGNIFICANCE: Autophagic effects via the mTOR signalling pathway may play a role in IRB's antifibrotic effects. Consideration of IRB as a therapeutic antifibrotic agent in pulmonary fibrosis needs further experimental and clinical long-term validation, especially in comorbid with primary hypertension, heart failure, and diabetic renal insults.

Synthetic antiprotozoal thiazolide drug induced apoptosis in colorectal cancer cells: implications of IL-6/JAK2/STAT3 and p53/caspases-dependent signaling pathways based on molecular docking and in vitro study.

Colorectal cancer (CRC) is a global pressing healthcare priority. Dysregulation of the IL6/JAK2/STAT3 and p53/caspase downstreaming pathways are significantly involved in the progression of CRC, and mainly affecting apoptosis. Discovery of new anti-cancer agents is laborious, time consuming, and costly with obvious socioeconomic burden. In the present study, we are proposing new molecular insights on the anti-proliferative and apoptotic therapeutic effects of nitazoxanide (NTZ) on CRC. NTZ is FDA-approved thiazolide antiparasitic agent, which has excellent safety and pharmacokinetic profiles. The molecular docking study revealed that NTZ has better binding affinity and docking score against JAK2 and BCL2 proteins compared to 5-Fluorouracil, which is the standard drug for treatment of CRC. The current in vitro work on a human HCT116 cell line displayed that NTZ had lower IC50 value (11.20 µM) than 5-flurouracil (23.78 µM), and NTZ induced a statistically significant down-regulation of IL6/JAK2/STAT3. NTZ also modulated significantly the p53/caspases-dependent signaling pathways, leading to enhancement of apoptosis and an increase of DNA fragmentation. Moreover, NTZ regulated the Bcl-2 gene family and promoted the loss of mitochondrial function which was depicted by release of cytochrome c (Cyt c), and caspase activation in apoptotic HCT116 cells. Additionally, NTZ was able to reduce the expression of VEGF in CRC cell line, which needs future thorough molecular investigations. In conclusion, our findings provided a novel evidence that NTZ could be a dual potential IL6/JAK2/STAT3 signaling inhibitor and p53/caspases-dependent pathway activator in CRC cell line. These potentials support further exploratory molecular researches targeting the therapeutic roles of NTZ in CRC; individually and simultaneously with current approved chemotherapeutic regimens.

Neuroprotective effects of ranolazine versus pioglitazone in experimental diabetic neuropathy: Targeting Nav1.7 channels and PPAR-γ.

Diabetic neuropathy (DN) is a common complication of diabetes mellitus (DM). Pathophysiology of DN includes inflammation and changes in expression and function of voltage-gated sodium channels (Nav) in peripheral nerves; and central reduction of Peroxisome Proliferator Activated Receptor-Gamma (PPAR-γ) expression. AIM: This study explored the effect of ranolazine (RN) versus pioglitazone (PIO) in DN induced in rats. The role of sciatic interleukin (IL)-1ß, tumor necrosis factor-alpha (TNF)-α, Nav1.7, and spinal PPAR-γ expressions were determined. MATERIALS AND METHODS: For induction of Type-2 DM, 40 high fat diet-fed rats were challenged by a single dose of intraperitoneal streptozotocin (30 mg/kg). One week later, oral PIO (10 mg/kg; once daily) or RN (20, 50 and 100 mg/kg; twice daily) were administered for six weeks. Weekly body weight and fasting blood sugar (FBS) were measured. Rats were tested for thermal hyperalgesia and mechanical allodynia. At the end of the experiment, sciatic nerves homogenates were examined for TNF-α and IL-1B levels, and Nav1.7 channel expression. Segments of spinal cords were investigated for the PPAR-γ gene expression. Evaluation of histopathology of sciatic nerves and spinal cords were done. KEY FINDINGS: In diabetic rats, PIO and RN individually improved evoked-pain behaviors, reduced sciatic TNF-α and 1L-1B levels; downregulated expressional levels of Nav1.7 channels; and increased the spinal PPAR-γ gene expression. RN in the dose of 100 mg/kg/day showed the most advantageous effects. SIGNIFICANCE: RN has neuroprotective effects in Type-2 diabetes-induced DN. Further studies of combined RN-PIO treatment are recommended, especially in diabetic patients with cardiovascular co-morbidity.

New insights on the modulatory roles of metformin or alpha-lipoic acid versus their combination in dextran sulfate sodium-induced chronic colitis in rats.

BACKGROUND: Dextran sulfate sodium (DSS)-induced colitis is the most widely used model that resembles ulcerative colitis (UC) in human with challenging chronic mechanistic oxidative stress-inflammatory/immunological cascades. In models of acute colitis, reduction of oxidative stress and inflammatory burdens beside manipulation of many transcriptional factors were achieved by metformin or alpha-lipoic acid (α-LA). Currently, in vivo DSS-induced chronic colitis was conducted and the possible therapeutic roles of metformin and/or α-LA were explored. METHODS: Chronic UC was induced by adding 5% DSS orally in drinking water for 7days followed by 3% DSS in drinking water for 14days in adult male albino Wistar rats. Intraperitoneal administration of α-LA (25mg/kg, twice/day) and/or metformin (100mg/kg/day) were set at day 7 of DSS administration and continued for 14days. Body weights, survival rates, disease activity index (DAI), colonic oxidative stress markers, tumor necrosis factor (TNF)-α levels, colonic nuclear factor-kappa-B (NF-κB) immunohistochemical expression, and the colonic histopathological changes were observed. RESULTS: Metformin or/and α-LA attenuated the severity of the DSS-induced colitis through improving the reductions in body weights, the DAI, the colonic oxidative stress markers, TNF-α, and NF-κB levels, and the morphological mucosal damage scores. Significant synergetic therapeutic effects were observed with combined therapeutic regimens. CONCLUSION: Therapeutically, metformin and α-LA could be administered in chronic colitis. The combination of currently used pharmaceutics with natural and synthetic potent antioxidant compounds will become a therapeutic strategy of choice for UC to improve the quality of life if sufficient clinical trials are available.

Assessment of the possible roles of SB-269970 versus ketanserin on carbon tetrachloride-induced liver fibrosis in rats: Oxidative stress/TGF-ß1-induced HSCs activation pathway.

BACKGROUND: In liver fibrosis, a major morbid and mortal disease, oxidative stress motivation of hepatic stellate cells (HSCs)-into myofibroblasts terminated in collagen deposition remain the key pathophysiological deal. Serotonin (5-HT) through its HSCs-expressed receptors, especially 5-HT2A and 7, shows crucial events in fibrogenesis of chronic liver diseases. Molecular hepatic oxidative stress-fibrotic roles of 5-HT2A and 7 receptors antagonists (ketanserin and SB-269970 respectively) are still a challenging issue. METHODS: Seven groups of adult male Wistar rats (n=10) were used. A carbon tetrachloride (CCl4) solution was injected intraperitoneally twice weekly for 6 weeks. On the 7th week, rats developed liver fibrosis were treated either by ketanserin (1mg/kg/day, ip) or SB-269970 (2mg/kg/day, ip) for 14days. Survival rates, and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in addition to hepatic malondialdehyde (MDA) and reduced glutathione (GSH) levels, superoxide dismutase (SOD) and catalase (CAT) activities, and transforming growth factor-beta1 (TGF-ß1) and procollagen type I N-terminal propeptide (PINP) levels, beside the hepatic histopathological fibrotic changes, were evaluated. RESULTS: In CCl4-challenged rats, each therapeutic approach showed significant reductions in elevated serum ALT, and AST levels, hepatic MDA, TGF-ß1, and PINP levels, and histopathological hepatic fibrotic scores as well as significant elevations in survival rates, reduced hepatic GSH levels, and SOD, and CAT activities. Remarkably, significant ameliorative measurements were observed in SB-269970 treated group. CONCLUSION: Blockade of 5-HT2A and 7 receptors each alone could be a future reliable therapeutic approach in liver fibrosis through a reduction in oxidative stress/TGF-ß1-induced HSCs activation pathway.

Modulation of the IL-23/IL-17 axis by fenofibrate ameliorates the ovalbumin/lipopolysaccharide-induced airway inflammation and bronchial asthma in rats.

The overlapping between asthmatic subtypes, including both CD4+ T helper (TH)2 and TH17 cells, is found in the natural course of allergic asthma, especially in exacerbations and severe and insensitive forms to steroids, which are in need of new molecular therapies. In the TH2-subset mediated asthma, fenofibrate displays therapeutic promises, besides evidenced therapeutic effects on TH17-mediated colitis and myocarditis. Therefore, the effects of fenofibrate versus dexamethasone on IL-23/IL-17 axis in ovalbumin (OVA)/lipopolysaccharide (LPS)-induced airway inflammation and bronchial asthma in rats were explored. The OVA/LPS sensitization and challenge were performed for 28 days in male Wistar rats. After sensitization, fenofibrate (100 mg/kg/day) or dexamethasone (2.5 mg/kg/day) was orally administered from the day 15 to 28. Either fenofibrate or dexamethasone attenuated the severity of OVA/LPS-induced airway inflammation and bronchial asthma through significant ameliorations in the total serum immunoglobulin (Ig)E assay; the total and differential leukocytic counts in the bronchoalveolar lavage (BAL) fluid; the lung inflammatory cytokines such as interleukin (IL)-4, IL-13, IL-17, and IL-23, transforming growth factor (TGF)-ß1, and tumor necrosis factor(TNF)-α levels; and the lung IL-17 and IL-23 expressions. In addition to the reduction in the inflammatory and fibrotic histopathological scores, fenofibrate significantly ameliorated the BAL neutrophilic count and the lung IL-17 and IL-23 expressions in comparison to dexamethasone. The suppression of IL-23/IL-17 axis could be considered a molecular therapeutic target for fenofibrate in OVA/LPS-induced airway inflammation and bronchial asthma. Combined therapeutic regimens of fenofibrate and steroids should be furtherly investigated in severe and resistant asthma.

Time-dependent therapeutic roles of nitazoxanide on high-fat diet/streptozotocin-induced diabetes in rats: effects on hepatic peroxisome proliferator-activated receptor-gamma receptors.

Targeting peroxisome proliferator-activated receptor-gamma (PPAR-γ) is an approved strategy in facing insulin resistance (IR) for diabetes mellitus (DM) type 2. The PPAR-γ modulators display improvements in the insulin-sensitizing and adverse effects of the traditional thiazolidinediones. Nitazoxanide (NTZ) is proposed as a PPAR-γ receptor ligand with agonistic post-transcriptional effects. Currently, NTZ antidiabetic activities versus pioglitazone (PIO) in a high-fat diet/streptozotocin rat model of type 2 diabetes was explored. Diabetic adult male Wistar rats were treated orally with either PIO (2.7 mg·kg-1·day-1) or NTZ (200 mg·kg-1·day-1) for 14, 21, and 28 days. Body masses, fasting blood glucose, IR, lipid profiles, and liver and kidney functions of rats were assayed. Hepatic glucose metabolism and PPAR-γ protein expression levels as well as hepatic, pancreatic, muscular, and renal histopathology were evaluated. Significant time-dependent euglycemic and insulin-sensitizing effects with preservation of liver and kidney functions were offered by NTZ. Higher hepatic levels of glucose-6-phosphatase and glucose-6-phosphate dehydrogenase enzymes and PPAR-γ protein expressions were acquired by NTZ and PIO, respectively. NTZ could be considered an oral therapeutic strategy for DM type 2. Further systematic NTZ/PPAR-γ receptor subtype molecular activations are recommended. Simultaneous use of NTZ with other approved antidiabetics should be explored.

The antifibrotic effects of alveolar macrophages 5-HT2C receptors blockade on bleomycin-induced pulmonary fibrosis in rats.

BACKGROUND: The most widespread chronic fibrosing lung disease is idiopathic pulmonary fibrosis. Lung serotonin (5-HT) content is increased during pulmonary fibrosis with the implication of 5-HT2 receptors in the pathogenesis. Serotonin plays important roles in alveolar macrophages function through 5-HT2C receptors activation. Numerous studies described the important role of 5-HT2A/B receptor blockers in suppressing different types of fibrosis as idiopathic pulmonary fibrosis. The current study pointed to examine the antifibrotic effects of RS-102221 and/or terguride through in vivo model of pulmonary fibrosis. METHODS: Induction of pulmonary fibrosis was through a single dose of intra-tracheal bleomycin instillation (5mg/kg dissolved in phosphate buffer saline) in adult male albino Wistar rats. Next day of bleomycin instillation, intraperitoneal injection of RS-102221 (0.5mg/kg/d) and/or terguride (1.2mg/kg/d) were administered and continued for 14 days. RESULTS: Noticeable increase in 5-HT2C receptors expression was observed in fibrotic lung tissues with marked allocation belonging to alveolar macrophages. Either RS-102221 or terguride reduced the increments in lung water contents, grading of lung fibrosis, lung tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-ß1) and vascular endothelial growth factor (VEGF) levels in lung injury and fibrosis-induced by bleomycin. Moreover, collagen content and myofibroblasts-alpha smooth muscle actin (α-SМA) were significantly decreased. Additionally, the simultaneous administration of RS-102221 with terguride had a synergistic outcome compared to that obtained by individual monotherapy. CONCLUSION: These findings suggested the potential use of 5-HT2A/B/C antagonists as anti-fibrotic agents in lung fibrosis.