Medical Sciences Project Topics

Effects of Marijuana Smoking on Some Cardiac Enzymes in Albino Rats

Effects of Marijuana Smoking on Some Cardiac Enzymes in Albino Rats

Effects of Marijuana Smoking on Some Cardiac Enzymes in Albino Rats

Chapter One



To determine the effects of marijuana smoking on some cardiac enzyme in Albino rats


  1. To determine the serum levels of CK-MB, LDH, AST and ALT in Albino        rats subjected to smoking.
  2. To determine the serum level of CK-MB, LDH, AST and ALT in Albino     rats that were not subjected to smoking
  3. To evaluate the influence of duration of marijuana smoking on some cardiac enzymes (CK-MB, LDH, AST, ALT).



Origin of Marijuana

The term “marijuana” is a word with indistinct origins. Some believe it is derived from the Mexican word for “Mary Jane”. Others held that “marijuana” comes from the Portuguese word ‘mariguano’ which means “intoxicant” (Pillard, 2000). The plant has been grown for fiber and as a source of medicine for several thousand years, but until 500 A.D its use as a mind-altering drug was almost solely confined in India. The drug and its uses reached the middle and near East during the next several centuries and then moved across North  Africa, appeared in Latin America and the Caribbean and finally entered the united states in the early  decades of this century (Pillard, 2000).

It is a traditional Chinese medicine that was initially spread in part due to its medicinal properties but also for utilizing materials from the hemp plant for manufacturing. Nowadays, it is most well known and used for its psychoactive properties although it still has some medicinal importance.

Components of Marijuana

Marijuana is a green mixture of dried shredded flowers and leaves of hemp plant. It has the following constituents: Dranabinol, Cannabidol and Cannabinol (Sharma et al., 2012)

DRANABINOL (Tetrahydrocannabinol)

Dranabinol is the main psychoactive substance found in hemp specie (marijuana). It has a chemical formula C2H3O2 and a molecular weight of 314.46g mol-1. (Baczynky and Zimerman, 2010). In its pure form, it’s a glassy solid when cold and become viscous and sticky if warm. THC has a low solubility in most organic solvent such as pure ethanol or hexane. (Willet et al., 2008). The pharmacological actions of Dranabinol are as a result of its binding to the cannabinol receptor CBI located in the brain and membrane of some cardiac muscle.


Cannabidol is a non-psychoactive cannabinoid in hemp plant cannabis sativa. It has a chemical formula C12H3O2 and a molecular weight of 314-46 mol-1. (Baczynky and Zimmerman, 2010). It has a melting point between 66-67◦C (Willet et al., 2008).


This is an active component of cannabis and is also the primary product of  Dranabinol (THC) degradation. Cannabinol content increases as THC degrades in storage and with exposure to light and air. CBN is mildly psychoactive (Baczynky and Zimmerman, 2010).

Pharmacologic Response and Metabolism of Marijuana.

Marijuana is metabolized extensively to a large number of compounds most of which are inactive. The principal urinary metabolite is Δ9-tetra hydrocannabinol-9-carboxylic acid (THC-COOH) and its glucoronide conjugate. (William and Thomas, 2005). The major psychoactive effects of THC are euphoria and sense of relaxation and well being. These effects occur within minutes of marijuana smoking reach a peak in about 15-30 minutes and May persists for 2-4 hours. Associated with this are a loss of short term memory and impairement of intellectual performance. (Sharma et al., 2012). After an individual inhales marijuana smoke, THC is absorbed rapidly through the lungs and reaches peak blood concentration within minutes. Thereafter, blood concentration rapidly declines to about 10% of peak levels within 1-2 hours. This rapid decline in THC concentration is as a result of its distribution to tissues such as brain,heart, fat and muscle. The rapid tissue distribution phase, a consequence of the lipophilic nature of THC is followed by a slow redistribution of the THC back into the blood stream and subsequent hepatic elimination. The terminal elimination half-life of THC is about one day in casual marijuana users and 3-5 days in chronic users. The peak psycho-active effects of THC generally lag behind the peak blood concentration by about 20-30 minutes.





  1. Housing: A total number of 18 healthy Albino rats weighing 160-200 grams and 6-7 weeks old were used for the study. Animals were procured from Emii Veterinary clinics in Owerri. They were housed in iron cages at the school farm of Imo state university and allowed to acclimatize for two weeks before the commencement of the experiment. The animals housing facilities were maintained at an ambient temperature of 250 C-300 C with a 12 hour each of dark and light cycle in the animals on sterility was maintained by cleaning the baskets daily.
  2. Feeding: The rats were fed with standard growers mash feed purchased at Emii veterinary clinic and water throughout the duration of the experiment. The principles of Animal care were followed and instructions given by institutional animal ethical committee were followed throughout the experiment. The animals were assigned to three groups of six(6) animals each.


A free, fresh leaves of cannabis sativa were collected from Agronova (Songhai farms) Nekede. The leaves were authenticated by Dr. F.N Mbagwu of plant science and Biotechnology Imo State University, Owerri.

Healthy, fresh leaves of cannabis sativa were sorted, washed to remove debris and dust particles with squeezing and them shade dried for 5 days. The dried leaves were milled into a fine powder using master chief home blender BW 680 379W.



Table 4.1: Result showing mean ± standard deviation of body weights of the three groups of rat in gram(g)





Delta-9-tetrahydro cannabinol (THC) is the most active component of marijuana (cannabis). THC causes direct activation of vascular cannabinoid CBI receptors by binding to it leading to change in membrane structure of the myocardial cells and eventually myocardial damage and shock resulting to the leakage or enzymes (AST, ALT, LDH, CK-MB) into the systemic circulation (Wagner and Batkair, 2005).  The use of enzyme markers such as AST, ALT, LDH and CK-MB are of major contributions in the diagnosis of cardiac diseases. In this present study with marijuana leaves, it was observed that there was a significant increase (P<0.05) in the serum levels of cardiac enzymes (AST, ALT, CDH and CK-MB) in the group 2 Albino rats treated with marijuana leaves when compared with the group 1 Albino rats that was not given marijuana leaves. This shows that marijuana smoking could increase the risk of coronary Atherosclerosis which could lead to myocardial ischemia or infarction resulting from the inability to increase coronary artery blood flow across the restriction in the vessels (Mouzak et al., 2009). From the results obtained it was observed that in all the enzymes elevated as a result of marijuana intake, it was found that CK-MB was highly increased more than the other enzymes. This shows that CK-MB is highly specific for myocardial injury and therefore it should be monitored closely in those addicted with marijuana consumption to prevent myocardial injury. When the dosage was increased from 10mg in group 2 to 20mg in group 3, it was found that the cardiac enzymes (AST, ALT, LDH and CK-MB) was significantly increased more than the group 2 and group 1 rats. The mean value of CK-MB was significantly increased more than the other enzymes.

Rosalki, (2009), reported elevation of 20-200 times normal value of CK-MB, LDH, AST and ALT activity among Albino rats treated with marijuana leaves compared with the Albino rats not treated with marijuana leaves. Although some studies have regarded the use of marijuana leaves in the treatment of illnesses but consuming it via smoking is highly toxic to the heart tissues.


The results of this study showed that marijuana leaves could probably have a cardiotoxic effect and it is not adviced to be consumed at all. The leave may have a toxic effect on the cardiac tissue thereby elevating cardiac enzymes. Also from the study it was found that the more the dosage, the more the increased risk of developing many cardiovascular diseases.


It is therefore recommended that individual that consume marijuana by any route should try as much as possible to stop because of the dangerous effects it has on the heart. It is also recommended that serious punishment should be  given to those people in which marijuana is found in their possession in order to discourage potential users from using marijuana.

However, further research should be carried out with other cardiac markers in other to confirm the cardiotoxic effect of the marijuana leaves being studied here.


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