Research code: IR.DUMS.REC.1400.013
Ethics code: IR.DUMS.REC.1400.013
Clinical trials code: IR.DUMS.REC.1400.013
Fatemeh Golshokouh 
, Ali Akbar Oroojan , Mehdi Hashemi , Seyedeh Mahsa Poormoosavi , Mojtaba Dolatshahi , Anahita Mohammadi
, Ali Akbar Oroojan , Mehdi Hashemi , Seyedeh Mahsa Poormoosavi , Mojtaba Dolatshahi , Anahita Mohammadi
Department of Physiology, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran. , aliakbar_oroojan@yahoo.com
Abstract: (362 Views)
Introduction: Nicotine is a type of alkaloid belonging to the nightshade family. Nicotine consumed by tobacco is the second most consumed substance in the world after caffeine in coffee and tea. Tobacco/Nicotine is consumed regularly in all countries, cultures, and almost religions. In 2012, it was found that in the European :union:, 32% of men and 24% of women used this combination. The prevalence of daily smoking in Iran in men and women is 24.3% and 9.2%, respectively. This trend can increase significantly in the coming years due to the increase in the adult population. Nicotine can cause oxidative stress by increasing the production of reactive oxygen species (ROS), reducing the content of glutathione and antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) in different tissues. Nicotine exposure clearly supports the idea that nicotine can induce damage to the pancreas. The mechanism through which nicotine induces such effects may be through signal transduction pathways in pancreatic cells, leading to an increase in the level of intracellular calcium release, cytotoxicity, and ultimately cell death. Induction of pancreatic injury by nicotine may also involve the activation and expression of the proto-oncogene, H-ras, which can increase cytosolic calcium through secondary messenger pathways. Also, this substance can increase lipid peroxidation and oxidative stress in pancreatic tissue and participate in the pathogenesis of pancreatic inflammation. Corn silk is used as an important traditional medicine in China. Phenolic compounds may prevent various diseases related to oxidative stress, such as cancer, high blood pressure, and cognitive dysfunction, which cause this action through the elimination of reactive oxygen species (ROS). Corn silk contains steroids such as stigmasterol and sitosterol and tannins. The biological activities of corn silk have been widely discussed in various studies, which include antioxidant, anti-diabetic, anticoagulant, anti-inflammatory, anti-cancer, and anti-obesity activities. Also, the methanolic extract of corn silk has been able to reduce lipid peroxidation in the kidney due to its antioxidant effects. Therefore, considering the high consumption of nicotine and the disruption of the pancreas through increasing oxidative stress and reducing antioxidant activity, and the effect of corn silk on improving the antioxidant balance in different parts of the body, the present study was conducted to investigate the protective effect of aqueous and methanolic extracts of corn silk on pancreatic function disorders induced by nicotine in male mice.
Materials and Methods: In the present laboratory study, 30 male laboratory mice of the NMRI breed, weighing between 25 and 30 grams, were obtained from the animal reproduction and care center of Dezful University of Medical Sciences and kept in a 12-hour light-dark cycle, also free access to standard food and water. Then the animals were divided into 6 groups (n=6): control, sham, nicotine (2.5 mg/kg) (intraperitoneal injection), nicotine (2.5 mg/kg) + aqueous extract of corn silk 400 mg/kg, nicotine (2.5 mg/kg) + 400 mg/kg corn silk methanolic extract (orally), the duration of using nicotine and extracts was 1 month at the same time. 24 hours after the last gavage of aqueous and methanol extracts of corn silk, the animals were subjected to deep anesthesia with the ketamine-xylazine combination (70 mg/kg - 10 mg/kg), then with a drop of blood, glucose was measured from the animal's tail, and by taking blood from the animal's heart and separating the serum from that, the insulin hormone concentration was investigated using the ELISA method. On the other hand, a part of the pancreas of mice was homogenized using phosphate buffer saline and after centrifugation at 5000 rpm for 10 minutes, the supernatant sample was used to measure MDA and GSH levels. In order to measure the indices of insulin resistance (HOMA-IR) and beta cell function (HOMA-β), the following formulas were used.
HOMA-IR = fasting insulin (µIU/dL) × fasting glucose (mg/dL)/405
HOMA-β = 360 × fasting insulin (µIU/dL) / fasting glucose (mg/dL) - 63
Also, at the end of the experiment, after deep anesthesia, the samples of pancreatic tissue were quickly removed and fixed in 10% formalin. After tissue processing, 5 to 7-micron paraffin sections were prepared. Sections were stained with hematoxylin and eosin and tissue changes were examined under a light microscope. From each animal, at least 6 slides were taken for each tissue and finally, the slides were examined by light microscope.
Results: There was no significant difference in body and pancreas weight, serum glucose, and insulin levels in the different groups. HOMA-IR in mice receiving nicotine increased significantly compared to the control group (P<0.05). Also, the use of aqueous and methanol extracts of corn silk in the groups receiving nicotine led to a decrease in this variable compared to the nicotine group, and this change was significant in the methanol extract group (P<0.05). The percentage of HOMA-β in the group injected with nicotine decreased significantly compared to the control group (P<0.01). Also, this index showed a significant increase in the groups receiving nicotine treated with aqueous and methanol extracts of corn silk compared to the group receiving nicotine alone (P<0.05). The results of the MDA assay as a factor indicating lipid peroxidation in the pancreatic tissue of the nicotine-receiving group showed a significant increase compared to the control group (P<0.01). This variable decreased significantly in the nicotine group plus aqueous and methanol extracts of corn silk compared to the nicotine group (P<0.01). GSH values as a factor indicating the changes of pancreatic tissue glutathione in the groups receiving nicotine and nicotine plus aqueous and methanolic extracts of corn silk decreased significantly compared to the control group (P<0.05). The results of histological examinations indicated a decrease in the diameter of the islets of Langerhans in the nicotine group compared to the control group. Also, this variable increased in the groups receiving aqueous and methanol extracts of corn silk compared to the nicotine group. Also, the necrosis of acinar cells was also evident in the group receiving nicotine compared to the control group, and this change was improved in the nicotine groups plus aqueous and methanol extracts of corn silk.
Conclusions: In conclusion, the results of this study showed that however, the use of nicotine in small laboratory mice did not significantly increase glucose and insulin in the body, but after the calculations, the insulin resistance indices increased and the function of pancreatic beta cells decreased. Therefore, these results show that the use of nicotine causes the body to advance towards diabetes type 1 and 2, which may be achieved with longer use of nicotine in laboratory animals. On the other hand, the use of aqueous and methanolic extracts of corn silk led to the improvement of disorders induced by nicotine, and this effect was more evident in the use of the methanolic extract. Finally, one of the main mechanisms involved in inducing damage by nicotine was the increase of lipid peroxidation and the decrease of glutathione, which was shown by the enhancement of MDA and reduction of GSH. Also, the use of aqueous and methanolic extracts of corn silk after improving the hormonal and biochemical alterations induced by nicotine showed protective effects on the pancreas tissue of these animals.
Materials and Methods: In the present laboratory study, 30 male laboratory mice of the NMRI breed, weighing between 25 and 30 grams, were obtained from the animal reproduction and care center of Dezful University of Medical Sciences and kept in a 12-hour light-dark cycle, also free access to standard food and water. Then the animals were divided into 6 groups (n=6): control, sham, nicotine (2.5 mg/kg) (intraperitoneal injection), nicotine (2.5 mg/kg) + aqueous extract of corn silk 400 mg/kg, nicotine (2.5 mg/kg) + 400 mg/kg corn silk methanolic extract (orally), the duration of using nicotine and extracts was 1 month at the same time. 24 hours after the last gavage of aqueous and methanol extracts of corn silk, the animals were subjected to deep anesthesia with the ketamine-xylazine combination (70 mg/kg - 10 mg/kg), then with a drop of blood, glucose was measured from the animal's tail, and by taking blood from the animal's heart and separating the serum from that, the insulin hormone concentration was investigated using the ELISA method. On the other hand, a part of the pancreas of mice was homogenized using phosphate buffer saline and after centrifugation at 5000 rpm for 10 minutes, the supernatant sample was used to measure MDA and GSH levels. In order to measure the indices of insulin resistance (HOMA-IR) and beta cell function (HOMA-β), the following formulas were used.
HOMA-IR = fasting insulin (µIU/dL) × fasting glucose (mg/dL)/405
HOMA-β = 360 × fasting insulin (µIU/dL) / fasting glucose (mg/dL) - 63
Also, at the end of the experiment, after deep anesthesia, the samples of pancreatic tissue were quickly removed and fixed in 10% formalin. After tissue processing, 5 to 7-micron paraffin sections were prepared. Sections were stained with hematoxylin and eosin and tissue changes were examined under a light microscope. From each animal, at least 6 slides were taken for each tissue and finally, the slides were examined by light microscope.
Results: There was no significant difference in body and pancreas weight, serum glucose, and insulin levels in the different groups. HOMA-IR in mice receiving nicotine increased significantly compared to the control group (P<0.05). Also, the use of aqueous and methanol extracts of corn silk in the groups receiving nicotine led to a decrease in this variable compared to the nicotine group, and this change was significant in the methanol extract group (P<0.05). The percentage of HOMA-β in the group injected with nicotine decreased significantly compared to the control group (P<0.01). Also, this index showed a significant increase in the groups receiving nicotine treated with aqueous and methanol extracts of corn silk compared to the group receiving nicotine alone (P<0.05). The results of the MDA assay as a factor indicating lipid peroxidation in the pancreatic tissue of the nicotine-receiving group showed a significant increase compared to the control group (P<0.01). This variable decreased significantly in the nicotine group plus aqueous and methanol extracts of corn silk compared to the nicotine group (P<0.01). GSH values as a factor indicating the changes of pancreatic tissue glutathione in the groups receiving nicotine and nicotine plus aqueous and methanolic extracts of corn silk decreased significantly compared to the control group (P<0.05). The results of histological examinations indicated a decrease in the diameter of the islets of Langerhans in the nicotine group compared to the control group. Also, this variable increased in the groups receiving aqueous and methanol extracts of corn silk compared to the nicotine group. Also, the necrosis of acinar cells was also evident in the group receiving nicotine compared to the control group, and this change was improved in the nicotine groups plus aqueous and methanol extracts of corn silk.
Conclusions: In conclusion, the results of this study showed that however, the use of nicotine in small laboratory mice did not significantly increase glucose and insulin in the body, but after the calculations, the insulin resistance indices increased and the function of pancreatic beta cells decreased. Therefore, these results show that the use of nicotine causes the body to advance towards diabetes type 1 and 2, which may be achieved with longer use of nicotine in laboratory animals. On the other hand, the use of aqueous and methanolic extracts of corn silk led to the improvement of disorders induced by nicotine, and this effect was more evident in the use of the methanolic extract. Finally, one of the main mechanisms involved in inducing damage by nicotine was the increase of lipid peroxidation and the decrease of glutathione, which was shown by the enhancement of MDA and reduction of GSH. Also, the use of aqueous and methanolic extracts of corn silk after improving the hormonal and biochemical alterations induced by nicotine showed protective effects on the pancreas tissue of these animals.
Type of Study: Research |
Subject:
Physiology
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