The overall goal of this procedure is to use the modified Bergstrom technique to make a skeletal muscle biopsy sample from the vastus laterals of a human volunteer. This is accomplished by first anesthetizing the skin and subcutaneous tissue at the biopsy site. In the second step, an incision is made through the skin subcutaneous tissue, and fascia overlaying the skeletal muscle.
Next, the biopsy needle is advanced through the incisions into the skeletal muscle, and the biopsy sample is collected in the final step. The biopsy needle is carefully removed and the incision is closed with surgical adhesive. Ultimately, the skeletal muscle biopsy samples can be prepared for histological analyses and analyzed for biochemical alterations and the expression of specific proteins and genes under various exercise conditions.
This method can help answer key questions in the field of skeletal muscle physiology, such as what are the biochemical, molecular, and cellular responses to strenuous exercise. Demonstrating the procedure will be Dr.Gerald Ferris, the physician from our local hospital, and Maschi Tanaka, a technician from our laboratory. After obtaining informed consent, instruct the subject to lie supine on a padded table with the thigh exposed position the leg in a relaxed manner with a small towel roll under the heel such that the knee is fully extended and elevated approximately one centimeter.
Next, instruct the subject to momentarily contract the exposed thigh muscle so that the vast lateralis biopsy site can be visualized just anterior to the fascia. Lata approximately one third of the distance between the top of the patella and the greater trocanter. Then use clippers to remove the hair from an approximately 15 by 15 centimeter region around the biopsy site and sterilize the area with swabs pre soaked in a topical antiseptic to harvest the biopsy using proper PPE and a septic technique.
First spray ethyl chloride on the incision site until the skin appears to blanch. Next, insert a 25 gauge needle horizontally into the dermis, aspirate the needle and dispense approximately 100 microliters of lidocaine to produce a two to four millimeter diameter bleb under the skin surface. Then advance the needle into the subcutaneous tissue, aspirate again and dispense approximately one milliliter of lidocaine to form another bleb.
Once the second bleb has subsided, insert the needle into the incision site, stopping superficial to the fascia, aspirate the needle one last time, and then slowly inject the remaining four milliliters of lidocaine while withdrawing the needle from the thigh. After two to three minutes, lightly probe the biopsy site with the tip of a sterile scalpel to confirm anesthetization. When the site is ready, make a straight one centimeter incision through the skin and subcutaneous tissues at a 45 degree angle with respect to the femur.
Then once in each direction, insert the scalpel deep enough to make an incision through the fascia into the muscle. Generally individuals new to this method must be patient as they learn to sense the change in resistance between the subcutaneous tissue and the fascia when administering the local anesthetic and when cutting through the skin subcutaneous tissue and the fascia. Now introduce the biopsy needle into the tissue at the same angle that the incision was made until the tip enters the fascia.
Advance the needle just past the fascia at a downward angle as it is advanced into the muscle. Instruct the subject to remain relaxed and to not contract the thigh muscle while the needle is being advanced. Then once the biopsy needle is in position, open a disposable 60 milliliter syringe to the 40 to 50 milliliter mark to create suction within the biopsy needle.
Pull the inner trocar out approximately one centimeter to open the window of the outer cannula while maintaining the position of the outer cannula within the muscle. Then rapidly close the inner trocar to cut and collect the muscle sample. Next, open the stop cock to release the suction and rotate the biopsy needle 90 degrees, repeating the process up to three times for a total of four clips.
Then remove the biopsy needle from the thigh upon removal of the needle. Pull the inner trocar back one centimeter and visually inspect the lumen of the outer cannula to estimate whether an adequate amount of tissue was collected. Apply direct pressure to the biopsy site with sterile gauze and an ice pack for 10 to 15 minutes.
During this time, remove the tissue from the biopsy needle After icing, pull the incision closed with one hand while applying a single layer of surgical adhesive over the top of the dry incision with the other. After the adhesive cures for about 90 seconds, apply tape closures perpendicular to the incision, then place three to four two by two inch non-sterile gauze pads over the incision site and secure them with self adhering adhesive wrap to apply direct pressure to the tissue. Finally, give the subject verbal and written instructions on proper wound care, normal and abnormal reactions and activity guidelines for the following, one to four days.
In a randomized placebo controlled crossover study, male endurance athletes ran on treadmills for three hours at 70%VO O2 max, and consumed a 6%carbohydrate or placebo beverage at a rate of one liter per hour. Skeletal muscle tissue biopsies were taken pre and post exercise, and gene expression of various cytokines were observed to be increased in skeletal muscle tissue obtained from experienced endurance athletes after three hours of running, interestingly, despite having no effect on skeletal muscle, glycogen depletion, carbohydrate intake was observed to attenuate IL six and IL eight mRNA levels After its development. This technique paved the way for researchers in the field of muscle physiology to explore principles such as fuel substrate utilization during different intensities of exercise, exercise induced muscle damage, and intercellular signaling among others.
