Riboflavin deficiency

In view of the important biochemical reactions involved in the intracellular flavoprotein, the typical symptoms of animals lacking riboflavin have been reported, including skin, mucous membrane, hair, eyes, reproduction, nervous system, blood system and congenital malformation of offspring In the absence of riboflavin, the rats may suffer from depilation, uneven hair growth, scaly skin, red lips, abnormal filiform papillae of the tongue, conjunctivitis, ophthalmopathy, corneal vascularization, corneal haze, neurodegeneration, hemoglobin reduction and cessation of estrous cycle In the newborn animals with riboflavin deficiency in female rats, hypoplasia and congenital malformation are common The bone system is first affected, which is characterized by short mandible, cleft palate, shortened limbs, tail and toe Congenital abnormality not only occurs in the skeletal system, but also hydrocephalus, eye damage, heart abnormality and hydronephrosis The rate of stillbirth is very high According to the biochemical study of mouse fetus, it was found that the decrease of FMN, fad and riboflavin in the liver was used to explain the biological oxidation of electron transport chain in the critical period of pregnancy In the tissues of riboflavin deficient animals, FMN and fad decreased, and the activity of flavin kinase in liver decreased by about one-half The decrease rate of FMN concentration is higher than that of fad, which may increase the activity of fad pyrophosphorylase in the absence of riboflavin This may be an adaptive mechanism to conserve fad when FMN is consumed, because many important enzymes need fad as coenzyme Compared with normal rats of the same weight, rats without riboflavin consumed 15-20% more calories, which may be the reason for incomplete oxidation and low food utilization When pigs lack riboflavin, it is characterized by slow growth, skin inflammation, diarrhea, ataxia, neurodegeneration and cataract Weight loss, weakness, and ataxia can be seen in dogs without riboflavin When serious lack, it can cause limb spasm, unstable standing, bradycardia, arrhythmia, slow breathing and even coma In addition, anemia may occur Anemia may also be due to the lack of folate and other hematopoietic factors, which may affect the production of red blood cells When the dog lacks riboflavin, the pathological changes are fatty liver disease, bone marrow atrophy, pulmonary punctate hemorrhage, encephalospinal cord and peripheral nerve degeneration When monkeys lack riboflavin, weight loss, seborrheic dermatitis, depilation, ataxia of limbs, decrease of white blood cells and red blood cells, decrease of riboflavin and its derivatives in plasma and decrease of fad can be seen In recent years, in animals with riboflavin deficiency, metabolic changes may occur For example, the amount of labeled serine entering into liver microparticles is less than that of normal animals If riboflavin is given, the amount of entering into microsomes can be increased It can be concluded that riboflavin plays a role in protein metabolism In riboflavin deficient mice, the number of mitochondria in liver increased, the length of cristae increased, and after riboflavin administration, it could gradually return to normal In the later stage of riboflavin deficiency, the concentration of RNA and DNA in liver decreased Riboflavin deficiency can also cause the increase of amino nitrogen concentration, lipid metabolism and triglyceride in liver, muscle and plasma Riboflavin deficiency is often caused by unreasonable diet (decrease of vitamin intake) or increase of demand, absorption or utilization obstacle in some cases It is also often found in children's development, women's lactation, trauma, chronic consumptive diseases such as long-term low fever, rheumatic fever, tuberculosis, subacute bacterial endocarditis, chronic congestive heart failure, hyperthyroidism and cachexia Absorption and utilization disorders often occur in chronic diarrhea, gastrointestinal surgery and cirrhosis The early symptoms of riboflavin deficiency are usually mouth and eye diseases, pain of lips, mouth and tongue, and difficulty in eating and swallowing Visual symptoms include photophobia, tears, burning or itching eyes, visual fatigue, and loss of vision that cannot be explained by refraction errors The visible symptoms of riboflavin deficiency include cleft lip, angular stomatitis, seborrheic dermatitis, glossitis and corneal surface angiogenesis The damage of lips began to be red and denuded along the closed line or initially pale and the corners of the mouth were soft Dry lips and chapped lips are accompanied by superficial ulcers or crusts When the angle of the mouth is damaged, the fissure can extend the buccal mucosa about one centimeter or longer Cracks can also be covered by yellow scabs When healed, the scars remain at the corners of the mouth and the lips turn into wrinkles Damage to the corners of the mouth is known as angular stomatitis, in the older literature as infectious angular stomatitis, and lip damage as cleft lips The above symptoms are similar to niacin deficiency In fact, the two causes are often related Seborrheic dermatitis caused by riboflavin deficiency usually occurs in lips, buccal folds, alar, vestibule, corner of the eye, or ears It is characterized by oily scales, which are red in color, and the whole nasal bridge can be seen as fine line acne In addition, the scrotum or vulva dermatitis can also occur, which is characterized by redness, scaly appearance and skin peeling off In some cases, the skin is rough and exudative, and can be extended to adjacent thighs Riboflavin deficiency, the color of tongue can be changed into purplish red or magenta, the papilla of tongue is swollen or mushroom shaped, and the appearance is pebble like pattern In severe cases, the filamentous papillae completely fall off, the mycotic papillae increase in the tongue, and extensive fissures appear This is not only caused by the lack of riboflavin, but also often due to the lack of several B vitamins - niacin, folic acid and vitamin B12 The damage of the eyes includes hyperemia and hyperplasia of the corneal peripheral plexus, which can be seen under the slit lamp or strong light Then the corneal peripheral hyperemia, with the formation of blood vessels, with the proliferation of the capillary of the choroid plexus of large branches, extends to the surface of the cornea, forming a layer of circles or rings The corneal vascularization caused by riboflavin deficiency often occurs around the cornea and often in both eyes Dot like opacity of the cornea surface and corneal ulcer may develop, which can be identified by fluorescein (yellow) staining There are also diffuse inflammation of the conjunctiva, redness of the eyes and faces, and sticky secretion In the treatment of riboflavin, the symptoms of eye damage can not be completely improved Anemia caused by riboflavin deficiency is often related to the disorder of folate metabolism The decrease of folate in blood is accompanied by the hypoplasia of reticulocytes and bone marrow cells, and the decrease of iron entering into erythrocytes Because riboflavin is necessary for growth So when riboflavin is deficient, it can also affect tissue regeneration and repair of the wound site.